Citation
Citrus propagation

Material Information

Title:
Citrus propagation
Series Title:
Florida Agricultural Extension Service bulletin 139
Creator:
Camp, A. F. (Arthur Forrest), 1896-
Affiliation:
University of Florida -- Florida Agricultural Extension Service
Place of Publication:
Gainesville, Fla.
Publisher:
Agricultural Extension Service, University of Florida
Publication Date:
Language:
English

Subjects

Subjects / Keywords:
Agriculture ( LCSH )
Farm life ( LCSH )
Farming ( LCSH )
University of Florida. ( LCSH )
Agriculture -- Florida ( LCSH )
Farm life -- Florida ( LCSH )
Citrus fruits -- Propagation -- Florida
City of Tallahassee ( local )
Budding ( jstor )
Seedlings ( jstor )
Tree trunks ( jstor )
Spatial Coverage:
North America -- United States of America -- Florida

Notes

General Note:
"A revision of bulletin 96"
Funding:
Florida Historical Agriculture and Rural Life

Record Information

Source Institution:
Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location:
Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management:
All rights reserved, Board of Trustees of the University of Florida

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Bulletin 139 March, 1949
IA revision of Bulletin 56)

COOPERATIVE EXTENSION WORK IN
AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June 30, 1914)
AGRICULTURAL EXTENSION SERVICE, UNIVERSITY OF FLORIDA
FLORIDA STATE UNIVERSITY
AND UNITED STATES DEPARTMENT OP AGRICULTURE
COOPERATING
H. G. CLAYTON, DIRECTOR



Citrus Propagation

By A. F. CAMP



































Fig. 1.-Inserting bud freshly cut from budwood into scion.

Single copies free to Florida residents upon request to
AGRICULTURAL EXTENSION SERVICE
GAINESVILLE. FLORIDA








BOARD OF CONTROL

J. THOSE. GURNEY, Chairman, Orlando HOLLIS RINEHART, Miami
J. HENSON MARKHAM, Jacksonville N. B. JORDAN, Quincy
THos. W. BRYANT, Lakeland W. F. POWERS, Secretary, Tallahassee

STAFF, AGRICULTURAL EXTENSION SERVICE

J. HILLIS MILLER, Ph.D., President of the University1
H. HAROLD HUME, D.Sc., Provost for Agriculture1
H. G. CLAYTON, M.S.A., Director of Extension
MARSHALL O. WATKINS, M.Agr., Assistant to the Director

Agricultural Demonstration Work, Gainesville
J. FRANCIS COOPER, M.S.A., Editor'
CLYDE BEALE, A.B.J., Associate Editor'
RUBY NEWHALL. Administrative Manager'
J. LEE SMITH, District Agent
K. S. McMULLEN, B.S.A., District Agent
H. S. MCLENDON, B.A., Soil Conservationist
R. S. DENNIS, B.S.A., Executive Officer, P. & M. Admin.2
R. W. BLACKLOCK, A.B., Boys' Club Agent
A. L. SHEALY, D.V.M., Animal Industrialist'
C. W. REAVES, B.S.A., Dairy Husbandman
N. R. MEHRHOF, M.ACR., Poultry Husbandman'
WALTER J. SHEELY, B.S., Animal Husbandman
F. S. PERRY, B.S.A., District Agent and Asst. Poultry Husbandman
A. W. O'STEEN, B.S.A., Supervisor, Egg-Laying Test, Chipley
L. T. NIELAND, Farm Forester
C. V. NOBLE, PH.D., Agricultural Economist'
CHARLES M. HAMPSON, M.S., Agricultural Economist, Farm Management'
D. E. TIMMONS, M.S.A., Economist in Marketing
F. W. PARVIN, B.S.A., Assistant Economist
JOHN M. JOHNSON, B.S.A., Agricultural Engineer
FRED P. LAWRENCE, B.S.A., Acting Citriculturist
W. W. BROWN, B.S.A., Asst. Boys' Club Agent
A. M. PETTIS, B.S.A., Farm Electrification Specialist"
JOHN D. HAYNIE, B.S.A., Apiculturist
V. L. JOHNSON, Rodent Control Specialist'
J. RUSSELL HENDERSON, M.S.A., Agronomist'
F. S. JAMISON, Ph.D., Vegetable Crop Specialist'

Home Demonstration Work, Tallahassee
MARY E. KEOWN, M.S., State Agent
RUBY McDAVID, District Agent
ETHYL HOLLOWAY, B.S., District Agent
MRS. EDITH Y. BARRUS, B.S.H.E., District Agent
ANNA MAE SIKES, M.S., Specialist in Nutritiun
JOYCE BEVIS, M.A., Clothing Specialist
BONNIE J. CARTER, B.S., Home Improvement Specialist
GRACE I. NEELY, M.S., Asso. Economist in Food Conservation
LUCILLE RUSS, M.S.P.H., Rural Health Improvement Specialist

Nero Extension Work, Tallahassee
FLOY BRITT, B.S.H.E., Negro District Agent
J. A. GRESHAM, B.S.A., Negro District Agent

Cooperative, other divisions. U. of F.
2 In cooperation with U. S.









Citrus Propagation

By A. F. CAMP
Vice-Director in Charge, Citrus Experiment Station
Lake Alfred, Florida

CONTENTS
The Seedbed .......... ...... .......... ....... 3 Top-W working .................................. 30
Budding Nursery Stock ............. 9 W hitewashes ................................. 35
Handling Budded Trees ............... 22 Grafting ....................................... 37
Digging Nursery Trees ...... ......... 23 Inarching .......................................... 41
Packing Nursery Stock for Rooting of Cuttings .................... 45
Shipment ..................................... 26 Transplanting Large Citrus Trees 48

The growing of citrus fruits in Florida began with seedling
trees. As the industry developed the superiority of budded
stock over the seedling tree became apparent and led to the
abandonment of the seedling method of propagation. Fortun-
ately, the propagation of citrus by budding and grafting is
very easy and its practice has extended beyond the nurseryman
to the grove owner himself. Today many citrus growers, even
including those with only a few trees in their dooryards, have
acquired the skill necessary for the budding of nursery stock
and the topworking of older trees.
The discussion of nursery practice given herein is based on
the best commercial practices of today, together with knowledge
gained in experimental work. A number of procedures are
listed that are not in general commercial use but which have
a certain amount of interest to growers at large.

The Seedbed
The seedbed should be located on good soil that is well drained
and capable of producing first-class growth of the seedlings.
It should be provided with irrigation, preferably of the over-
head type. Some nurserymen prefer to cover it with a lath
shade, although this is not necessary and the majority of seed-
beds are planted in the open. The lath shade has a tendency to
increase the amount of seedling diseases and makes the seedbed
difficult to handle from this standpoint but minimizes the mois-
ture problem (see Figs. 2, 3 and 4). The location selected
should be well protected from cold and the soil should be well
drained, as this will reduce the trouble from seedling diseases.
A fertile soil is of course desirable but it is sometimes necessary
to sacrifice soil quality somewhat for the sake of good cold























F--


Fig. 2.-Nursery seedbed and very young seedlings. (Courtesy Glen St. Mary Nurseries.)








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L' j~ :k I

I ~ r hj ~lf"l'y~


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6


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Fig. 3.-Nursery seedbed and seedlings almost ready to transplant to nursery row. (Courtesy Glen St. Mary Nurseries.)


4ft V.







Florida Cooperative Extension


protection and good drainage. It is also desirable to use new
land whenever possible and not to plant a bed the second time
without letting it "lay out" for a while. The same rules apply
to the selection of land for nursery rows.


Fig. 4.-Citrus nursery seedbed under shade. (Courtesy Glen St. Mary
Nurseries.)

A small amount of fertilizer is needed in making up the seed-
bed. This fertilizer should have a high percentage of nitrogen,
largely derived from organic sources. Several weeks before
the seeds are planted the fertilizer should be added and worked
thoroughly into the soil.
Where only a small seedbed is desired the seeds are planted
in rows wide enough for hand cultivation, but where a large
number of seedlings are being grown the rows are laid out
wide enough for horse-drawn cultivation. The seeds are planted
thickly in the row and are covered with two to three inches







Citrus Propagatiqij


of soil. Sour orange, sweet orange, grapefruit and rough lemon
seeds are planted after the danger of frost is over, as very
young seedlings are killed when frozen to the ground. Poncirus
trifoliata seedlings are not completely killed by being frozen off,
but sprout up from below ground; consequently, seeds of this
species can be planted whenever they are ready.
The number of days required for germination of citrus seeds
will depend upon soil temperature and moisture and condition
of the seeds when planted. Experiments with fresh seeds have
shown that the optimum soil temperature for germination is
about 90 degrees F. Fresh seeds will sometimes germinate in
two weeks when the soil temperature is near 90 degrees F. but
require a longer time for germination when the soil temperature
is lower. During winter and spring the soil temperature is
much lower than optimum and the time required for germina-
tion is correspondingly longer. The seedlings, however, are
usually up in from three weeks to a month if the soil has been
kept moist and the weather is not too cold.
After the seedlings have come up it is necessary to cultivate
sufficiently to keep down weeds and to water enough to keep
the plants growing well but not so much as to cause damping-
off fungi to attack the seedlings. During the growing season
two or three applications of fertilizer having a high nitrogen
content should be made. Before the seedlings are removed
from the seedbed, cultivation and fertilization should be stopped
to allow the seedlings to harden up.
About one year from the September following the planting
of the seed, making about 18 months in the seedbed, the seed-
lings are transplanted to the nursery row for further growth
and budding. Seedlings are frequently transplanted after a
much shorter period in the seedbed but are harder to handle
in the nursery row because of their small size. The seedlings
can be removed by cutting the taproot 8 to 12 inches below
the surface with a nursery spade, after which the seedlings
can be easily lifted. The seedbed should be well watered just
before the seedlings are removed. At least twice as many seed-
lings should be grown as it is intended to plant and only the
best seedlings used.
In transplanting seedbed stock to the nursery row the soil
is usually opened with a spade. Care should be practiced to
prevent the doubling up of roots, particularly the taproot, when
planting. If necessary, prune back the roots before attempting











































Fig. 5.-Citrus seedlings in the nursery row ready to bud.







Citrus Propagation


to plant. Watering at the time of planting is highly desirable
if the soil is even slightly dry.
The nursery rows are usually three to four feet apart and
the seedlings are planted about 12 inches apart in the row, the
distance varying in different nurseries (see Fig. 5). Generally
speaking, the rows should be wide enough to permit the use
of a horse or mule in cultivating and the trees should be far
enough apart in the row to permit the free use of a hoe between
the trees. The trees are grown in the nursery row for about
one year before being budded. Budding is usually done in the
fall-September, October and November-but may be done also
in the spring or summer.

Budding Nursery Stock
The standard method of propagating citrus nursery stock is
by budding. While the seedlings can be readily grafted by
several different methods, these are never used in practice be-
cause budding is so much simpler, quicker and more economical
of budwood than is any method of grafting. Citrus can be
budded whenever the bark will "slip," that is, whenever it will
separate readily from the wood. This condition exists during
most of the spring, summer and fall, but in nursery practice
it is customary to do most of the budding during the fall. Bud-
ding at this time is called dormant budding because the buds
do not start into growth until the following spring. When
the stock is large enough to bud in the fall a delay until spring
will result in three to four weeks loss of growing time in the
budded tree.
Budding in citrus is accomplished by the insertion of a shield-
shaped bud into a "T" slot cut in the bark of the stock. The
leg of the "T" is parallel with the axis of the stock and the top
of the "T" across the stock at either the top or bottom, thus
making either an erect or inverted "T" as desired. The buds
are cut from wood about the size of a pencil or a little smaller,
which has outgrown its angular condition and will usually be
of the flush previous to the one occurring at the time the bud-
ding is done. In Fig. 6 are shown two types of budwood, namely,
the angled wood which is considered unsuitable, except for
certain special types of budding, and the round wood which is
desirable. The tree from which the budwood is selected should
bear satisfactory crops of fruit true to the varietal type.































































Fig. 6.-Citrus budwood. The wood on the left is too angular; that on the
right is of better quality.







Citrus Propagation


In nursery practice, buds are commonly taken from blocks
of nursery stock of the desired variety. When the block records
are accurate and where new budding material is obtained fre-
quently from bearing trees this practice is not as bad as it
would at first appear. A certain number of off-type trees will
appear but they may also appear in blocks budded from bearing
trees. This practice is quite common and, aside from other
considerations, has been followed because of the difficulty in
obtaining large amounts of suitable budwood from bearing
trees. If, as has happened in some cases, buds are obtained
only from nursery trees and several generations of trees are
produced entirely by transfer of buds from one block to another,
it may easily happen that a considerable number of off-type
trees may appear and if care is not continually practiced, some
mixing of varieties may occur. If buds taken direct from parent
trees are not obtainable in sufficient quantity, it is better to
bud a small block of nursery trees each year from suitable
bearing trees and to use buds from these for larger blocks the
following year. The constant reference back to bearing trees
in this way more nearly approximates the ideal system of ob-
taining all buds from bearing trees.
For the benefit of those just starting in the nursery business
and for those who are raising trees for their own groves, it
should be pointed out that there is considerable variation in
citrus varieties in Florida. In selecting bearing trees as a source
of budwood it is not sufficient to take any tree that has been
casually identified as belonging to a variety. Budwood should
be obtained from trees that have a record of good production of
true-to-type fruit and the greatest care should be used in this
selection. Trees that produce poor or freakish fruit usually will
transmit these characteristics to trees budded from them. It
is well to remember at all times that the new trees are not
likely to be any better than the tree from which the budwood
was obtained.
In selecting budwood much more care should be exercised
than has been the case in the past. Virus diseases such as
psorosis can be transmitted by budding and, in the case of
psorosis, this is the common method of transmittal. Unfor-
tunately, trees affected by psorosis do not always show the
characteristic gumming until they are 10 or 12 years old or
even older but it is in the system of the tree and buds taken
from infected trees will transmit the disease even though no







Florida Cooperative Extension


gumming is present. The presence of the psorosis virus in the
plant can be determined by expert examination of the leaves
of a new flush. If the tree is infected a characteristic flecking
can be seen. In the case of trees which are to be regularly used
as a source of budwood it is well to request expert help for
making this examination to be certain that the trees are not
infected. Carelessness in obtaining budwood has been respons-
ible for the widespread distribution of psorosis in Florida and
it should be remembered that trees may have it for many years
before showing the typical gumming and scaling on the trunks
or limbs. Preferably obtain starts of budwood from trees 25
years of age or older and examine them thoroughly before cut-
ting the budwood. In the case of the tristeza disease of South
America and quick decline in California, transmittal is possible
by budwood from infected trees.
For convenience in budding, the budwood is usually cut into
pieces from 8 to 12 inches long, each piece carrying several buds.
The budwood should be of good normal growth, well rounded
and sufficiently hardened to handle well. As soon as the bud-
wood is cut from the tree it should be defoliated by cutting the
leaves off with a knife or pruning shears, leaving a piece of each
petiole attached to the wood. When it is necessary to store the
budwood until the stock is ready for budding, the sticks can
be packed in cypress sawdust or in damp sphagnum moss and
held in a cool place. If stored in sawdust it will be necessary
to repack occasionally.
A knife having a blade of the very finest steel and with a
rounded end is necessary. The blade should be made of steel
comparable in quality to razor steel and carefully ground and
honed to a smooth, thin edge. Many very careful workers pre-
fer to finish sharpening the knife with a strop similar to a razor
strop. Unless the knife is of very fine quality and very carefully
sharpened, it is impossible to make smooth cuts and to open
up the bark without leaving loose shreds which interfere with
the insertion of the bud. Standard budding knives are com-
monly made with a bone handle with a flat, wedged end for
opening up the bark where necessary, but the handle is seldom
used by specialists in budding.
Budding tape for wrapping the buds is made from thin
bleached muslin put up in rolls six to eight inches long and one
to two inches in diameter. These are impregnated with a graft-
ing wax that will not harden. Of a large number of formulae







Citrus Propagation


for the wax, the one below, taken from Hume's "Cultivation of
Citrus Fruits," is considered very satisfactory for use under
Florida conditions.

R esin .............. ... ....... .......... 1 lb.
B eesw ax ........ ....... ...................... ....... 4 lbs.
Raw pine gum .. .... .... ....... 3 tbsps.

The grafting wax is heated over the fire until melted, a large
iron kettle generally being used, and the rolls are immersed
in it until thoroughly impregnated. The wax must not be too
hot during the procedure and a good practice is to bring the
wax to a boil so it can be skimmed, then allow it to cool some-
what before immersing the rolls of cloth. Plenty of time should
be allowed so as to obtain thorough penetration and the "oro-
cedure can be helped by moving the rolls around in the melted
wax. If the rolls of cloth are too large, the wax will not pene-
trate and the diameter, therefore, should be kept below two
inches. To secure better penetration, many workers tear the
muslin in 36-inch squares and fold these into smaller squares
for ease in handling prior to impregnation. These are immersed
in the melted wax and unfolded with sticks to make sure of
even penetration. The sheets are then stretched on bamboo
poles to drain and dry. After the cloth is cool it can be torn
off in strips the proper width for use, as needed.
Any number of variations of this procedure have been sug-
gested or adopted by various budders, according to personal
preferences. A good grade of muslin, put up in proper rolls
and thoroughly impregnated with wax, can be torn to any width
desired, whereas tapes and other materials made a definite
width beforehand lack the flexibility in handling afforded by
the above method of preparation. The cloth should be capable
of withstanding considerable pull and the wax should be one
that will retain a certain softness and not harden on exposure.
Budding in the nursery usually is carried out on seedling
trees from the size of a pencil up to an inch in diameter, but
trees 1/ to 3-inch caliper are most desirable; trees that are
too small should be discarded. The trunk of the seedling is
pruned clean of thorns and limbs, ahead of the budder so as to
save time, and the soil is scraped away if the bud is to be placed
close to the soil. With the knife grasped in the right hand and
the edge of the blade downward, a downward cut is made about
an inch and a half long (Fig. 7-A). This is a vertical cut
through the bark but no farther into the wood than is necessary





























































Fig. 7.-Initial steps in the budding process. A, making the vertical
cut; the cutting stroke is usually downward but may be made upward if
desired. B, making the cross cut at the bottom of the vertical slit; note
tilt of knife blade. C, cutting the bud shield from the bud stock. (Cf.
Fig. 8.)







Citrus Propagation


to be certain that the bark has been completely cut. If desired,
this cut can be made upward instead of downward. The knife
is now used to make a cross cut at the bottom of the vertical
cut, thus making an inverted "T" (Fig. 7-B). In making this
cut, the back of the knife blade is tilted slightly downward so
that the cut is a little upward as well as across the stock. At
the finish of the cut, the knife blade is tilted slightly upward
and given a slight twist to open the bark at the junction of the
horizontal and vertical cuts.
The bud is now cut from a stick of budwood held as in Fig.
7-C, with the basal end away from the operator. The cut is
toward the operator and is made as nearly as possible parallel
with the axis of the budwood, and with a light rotating motion.
The knife is held with the blade almost parallel to the axis of
the budwood and the thumb of the knife hand used to steady
the budwood in making the cut. This will give a shield-shaped
piece of bark and wood about three-quarters to one inch long
with a flat, smooth cut surface. The bud should not be scooped
out, as this will cause too much wood to be taken with the bud.
As the cut is finished, the thumb retains the bud on the blade
of the budding knife and at the lower end of the shield. Using
this method of holding the bud, with thumb and knife blade,
the upper end of the bud is inserted in the stock as in Fig. 8-D.
Another method of insertion is shown in Fig. 1 (front cover).
The bud shield when inserted is entirely beneath the bark and
should be pushed far up into the vertical cut (Fig. 8-E and F).
The bud should be handled very carefully so as not to injure
it during the procedure; inexperienced operators may tear up
the edge of the shield in the process of inserting it under the
bark and sometimes will use the point of the knife to push it
into place and badly injure the bud in this way. Considerable
practice is necessary to carry out the procedure rapidly and
smoothly so as to insert the bud into place with the edge of the
shield smooth and untorn and the bud uninjured, but unless this
is done the bud has a poor chance of "taking." The inexperi-
enced worker in watching the experienced budder frequently
gets the impression that the work can be rapidly and carelessly
done, whereas the speed really comes from a great deal of prac-
tice so that all operations are done accurately as well as rapidly.
Taping is started below the bud and the tape wrapped firmly
but not too tightly around the trunk of the tree up to above
the top of the vertical cut (Fig. 8-G and H). As the wrapping





























1


Fig. 8.-Final steps in the budding process. D, inserting bud shield
in stock; bud is being held on knife blade. E, bud shield in place in stock;
note that it is entirely within the flaps of bark. F, a closer view of the
shield bud in place. G, taping the bud; taping is started at the bottom
in inverted "T" budding and at the top in erect "T" budding. H, taping
finished; end of tape is brought back on tape wraps so that it will stick.
(Cf. Fig. 7.)







Citrus Propagation


is finished the end of the tape should be brought back onto the
cloth, as this will make it adhere more firmly. For wrapping
buds it is usually found desirable to tear the cloth in about
3/4-inch strips, but the size of the stock and other conditions
will influence this considerably. It is important that the wrap-
ping be sufficiently tight to prevent the entrance of water into
the wound and to hold the bud and the stock closely together
so that callousing will start and a union be formed. After 10
days to two weeks the buds can be examined and if still green
and showing callous formations indicating that they have
"taken," the tape can be removed.
The type of budding here illustrated is described as inverted
"T" incision. In California the erect "T" is used, that is, the
cross cut is made at the top of the vertical cut instead of at the
bottom as in the Florida method. It is claimed that the inverted
"T" method keeps out moisture better and allows the bud to
"drain," although the real reason is probably to be found in
custom, as either method will work satisfactorily. When the
erect "T" is used, the wrapping is started at the top, that is,
at the point of intersection of the two cuts.
The distance of the bud from the ground must be determined
by conditions under which the trees are to be used. Sweet
orange scions on sour orange stocks can be affected with foot
rot if water or mud stands above the bud union just as readily
as seedling sweet oranges can be attacked. Where the budded
trees are to be planted in moist locations, the buds should be high
above the ground but when they are to be planted on drier lands
the bud may be within two or three inches of the ground to
facilitate protection against cold by banking. Under Florida
conditions the buds usually are placed as close to the soil as
it is convenient to work, that is two or three inches.
When the bud starts to grow the seedling top is cut off
smoothly just above the bud, thus throwing the growth to the
bud. Dormant budded nursery trees are cut back in January
or February before spring growth starts. When the seedling
is very large at time of budding the top is sometimes "lopped"
when the bud starts, by cutting it partially through. This helps
to start the bud and at the same time leaves some top to sup-
port the roots (Fig. 9). Lopping reduces the chances of the
bud being flooded or drowned by excessive sap flow which may
occur if a vigorously growing top is suddenly removed. The
cut should be on the same side as the bud. After the bud shoot







Florida Cooperative Extension


-% U


*!
"t .. ". -


":,," '' .^ ." .'*~ w
^"^ '^('ii^^


Fig. 9.-"Lopped" seedling, showing bud that has just "taken."


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Fig. 10.-Field of budded trees. (Courtesy Glen St. Mary Nurseries.)


:4,,1







Florida Cooperative Extension


has grown 6 to 12 inches high, the old seedling top is entirely
removed with a pair of sharp clippers, making the cut close to
the bud. Lopping is seldom practiced in nurseries where seed-
lings of normal size are being budded but is sometimes used
where seedlings that have remained too long in the nursery
row are being worked.


Fig. 11.-Nursery trees staked and tied-wooden stakes.


As soon as the buds start to grow it will be necessary to put
a stake at each tree and to tie the shoot to the stake from time
to time with raffia or coarse string (see Figs. 10 and 11). The
stakes may be of good heart pine or cypress 3/4 to one inch
square and 4 feet long, or they may be of heavy galvanized
wire. If old stakes are used, they should be free of termite
and ant colonies. Many nurserymen using wooden stakes make
it a practice to place the stake on the north side of the scion
to give a little protection against the north winds. The best







Citrus Propagation


practice is to place the stake in the angle formed by the scion
and the stock. The stake is close to the scion, making training
easy, and out of the way of the cultivator. If the stake is
placed on the opposite side of the stock from the bud, the scion
will be bent in training. When the shoot is from one to three
feet high it is usually topped, thus starting the formation of a
framework for the tree. The height for topping is determined
by the operator to produce the type of tree desired.






















Fig. 12.-Side budding with curved incision on left and angled incision
on right. Either shield can be cut from angular budwood to better ad-
vantage than can the ordinary shield.

A large number of other methods of budding can be used but
are not ordinarily necessary in citrus. Some of these, such as
ring or patch budding, are particularly adapted to some trees
that are budded with considerable difficulty, usually due to a
thick and brittle bark, and which will not respond readily to
shield budding, but these methods are not used in citrus. Some
variations of the shield bud are used in working stocks that
are too hard or in utilizing budwood that is too angled to permit
the cutting of satisfactory shields of the usual type. Two
of these methods are illustrated in Fig. 12. These two pictures
represent types of what is called side budding, this method being







Florida Cooperative Extension


sometimes used on stocks that are too hard for the usual method
of shield budding. Note in particular the shape of the bud shield
with the bud eye on the side of the shield instead of in the center.
This type of shield can be readily cut from very angular budwood.
Except for the shape of the bud shield and the method of making
the incision in the stock, the procedure to be followed is the
same as that followed in "T" or inverted "T" budding. Occa-
sionally with either of these types of side budding a small sprig
of budwood with three to five buds on it is substituted for a
shield bud. This type of procedure is frequently used in ex-
perimental work where the wood available is too small for shields
to be cut from it.
In budding large blocks of nursery stock the pruner usually
cleans off the leaves, thorns and limbs where the bud is to be
inserted, ahead of the budder, and the pruner or another helper
will scrape away the soil, if this is necessary. The budder also
has a "tier" working with him who wraps the buds. Under
such conditions a good budder may put in as high as 1,500 or
more buds in a day, his efforts being entirely devoted to the
highly skilled operation of cutting and inserting the buds. In
nursery practice the tier always uses budding tape but where
small amounts of work are being done other methods of holding
the bud in place are sometimes used. The bud may be tied in
with raffia or string and the whole wound painted over with
melted paraffin and carnauba wax. In case this method is to
be used, a special lantern containing an alcohol lamp and a cup
in which the wax is melted should be obtained. Special wide
rubber bands also are used occasionally for tying.
In dormant budding it is sometimes necessary to protect the
bud from cold. This can be done by banking the trees with soil
after the wraps are removed, this being commonly done by
plowing a furrow to each side of the row. This soil is removed
immediately after the danger of frost is past.

Handling Budded Trees
Cultivation and fertilization of budded trees should be such
as to promote thrifty growth. The nursery rows are cultivated
frequently to keep down weeds and grass, a horse-drawn culti-
vator being used for cultivating the middles and the rows being
hoed out by hand. In the fall cultivation is reduced so as to
harden the trees before frost. The amount and type of fer-
tilizer will depend greatly on the type of soil. A fertilizer







Citrus Propagation


analyzing 4 to 5 percent nitrogen, 6 to 8 percent phosphoric
acid, 4 to 6 percent potash, 3 percent water-soluble magnesium
oxide, 4 percent manganese oxide and 1 percent copper oxide is
suitable. Three applications of fertilizer per season should be
made, the first just prior to the start of growth in the spring,
the second in June and the third in late August or early Septem-
ber. The amounts will vary from 500 to 1,500 pounds per acre
per application, depending on fertility of the soil. The applica-
tions may be made broadcast and worked in with the cultivator
but usually the first is applied by "barring off" the rows (plowing
a furrow away from each side of the row with a small turning
plow) and placing the fertilizer in the furrow and covering it
by plowing the soil back into the furrow. Too much fertiliza-
tion and cultivation should be avoided, as an excess tends to
produce too rank and soft a growth.
As pointed out previously, the scion must be tied to the stake
from time to time so that it will have a straight trunk. The
height at which it is to be topped to form the framework of
the tree will depend on the type of tree desired. Of late years
the tendency has been to the growing of low-headed trees and
the scions are usually topped at about 18 to 24 inches. In addi-
tion to the work of training the scion, sprouts must be removed
from both stock and scion occasionally. When the tree has
developed a strong trunk the stake is removed so that it will not
be in the way when the trees are dug.
Budded trees are allowed to grow at least one year in the
nursery row before being placed in the grove. The grading of
nursery stock after off-type and freak trees are eliminated is
usually done by caliper (i.e., the diameter of the trunk two
inches above the union is measured) and by the age of the trees
from budding. Trees for planting should preferably caliper
/8 inch or over after one year from budding. Two-year trees
should be larger. Trees that failed to make satisfactory growth
the first year are commonly left for another year's growth.
Some nurserymen prefer to cut back such trees to the bud and
make an entirely new top the second year but trees that are
badly stunted should be discarded.

Digging Nursery Trees
Nursery trees are dug as ordered and the selection of the trees
is based on the size desired to fill the order. In digging nursery
trees the foreman of the crew usually selects the trees to be








I


A *
S-r.

Fig. 13.-Digging nursery trees. A, tree


ready for digging. B, pruning back with lopping shears preliminary to digging.
(Cf. Figs. 14 and 15.)








F -


.4C
t-~--


WA


a' -l'


^ <
,l II
L 8i'.
*'


L -1* 'f :mp o w
r w 2 .* *
*i?.-& a


Fig. 14.-Digging nursery trees. C, tree pruned back for digging. D, digging the tree. The man on the right is cutting
the lateral roots with a spade; the one on the left is cleaning off the leaves and twigs remaining after pruning. (Cf. Figs.
13 and 15.)


1-


'4


Sr ~


.~

.

r;h"







Florida Cooperative Extension


dug and prunes them back with longhandled shears to a frame-
work or a stub, according to instructions (Fig. 13-A and B).
The remaining leaves and twigs are cut off with a knife or prun-
ing shears and the lateral roots are cut off in a circle around
the tree by means of long-bladed nursery spades (Fig. 14-D).
A hole is then dug on one side of the tree so that the spade
can be driven under the tree at the proper depth to cut the tap-
root (Fig. 15-E). The tree is then "lifted" with the help of the
spade and the roots are immediately covered to prevent drying
out (Fig. 15-G). The trees may be loosened as in Fig. 15-F
but have the roots still left in the soil until the truck or wagon
comes and then the trees can be quickly lifted and placed under
cover. It is very important that the roots should not be allowed
to dry out before planting. This applies not only to the process
of digging but also to the hauling and handling of trees, partic-
ularly when they are to be removed by truck or wagon directly
to the field where they are to be planted.
The practice of handling citrus nursery stock "bare rooted"
is universal in Florida. In California, however, the trees are
"balled," that is, dug with a ball of earth containing the roots
and this is wrapped with burlap (Fig. 16). Difficulties attached
to handling trees in this way in the light Florida soils are ob-
vious. Morever, the trees grow so readily when transplanted
under Florida conditions that this procedure is found to be un-
necessary.

Packing Nursery Stock for Shipment
Nursery trees are packed in various ways for shipment by
freight, express or mail. A larger proportion of the trees now
move by truck directly to the grove site and for short hauls are
commonly dug in the morning and planted in the afternoon.
If the trees are wet down as they are loaded onto the truck
and covered with wet canvas or burlap cover they can be handled
nicely for short hauls but for longer hauls it is desirable to pack
the roots in moist sawdust or other materials and also to cover
with a canvas to protect the top from the drying wind. All
methods of long distance shipment make use of some sort of
protection for the roots-such as moist sphagnum moss or
"shingle toe" (sawdust from cypress shingle mills). In Fig.
17-A is shown a standard crate for the shipment of nursery
trees. As shown in the figure, the crate is lying on its side
and it is placed in this position when the trees are packed in it.






















/


-


If "


Fig. 15.-Digging nursery trees. E, cutting taproot of tree with a spade; note depth to which spade is thrust into soil.
F, "lifting" a nursery tree; the worker's right hand holds the handle of the spade and with his hand and knee he is using
the spade to help pry the tree up. G, the nursery tree lifted free of the soil; note the fine root system. (Cf. Figs. 13 and 14.)


.1 --- 7- 1






Florida Cooperative Extension


The 2 x 2 inch framing piece for the open side is removed and
the box lined with paper before the packing starts. A layer
of moss or shingletoe is placed for the roots and excelsior is used
at the top of the box to protect the trunks against rubbing and
to keep the packing for the roots in place. The trees are packed
in tightly with alternate layers of packing material and finally
covered with a layer of packing material and paper. The fram-
ing piece is then nailed back in place and a piece of 1 x 3 inch
placed across the center of the open side and nailed to the sides
to help hold the trees in place. The side boards are then nailed
on and the box stood on end ready for receiving the burlap
covering to protect the tops of the trees (Fig. 17-B). The tops
of the trees are now covered with burlap which is attached to
the crate by means of lath strips nailed to the top frame and
securely sewed (Fig. 17-C). The crates shown are usually 30

Fig. 16.-Citrus nursery trees are balled and burlapped in California, but
usually are handled bare-rooted in Florida.


: i'r. ^f t,


I
~
--~L-=, z






























































Fig. 17.-Shipping nursery stock. A, shipping crate, with end and one
side (up) left open to facilitate packing. B, nursery stock crated and
ready for burlap covering over the tops. C, crated for shipment. D, four
types of packages for shipping citrus nursery stock. In the background
the crate, on the left the paper-wrapped parcel for mail shipment, center
corrugated paper and paper, and right burlap covering for express shipment.







Florida Cooperative Extension


inches high but the side dimensions may vary from 12 x 12
inches to much larger.
Smaller quantities of trees may be shipped in bales and three
types of bales are shown in Fig. 17-D. These vary from a paper
covered bale for mail order shipments to coverings of corrugated
paper and wrapping paper or burlap for express shipments.
In all cases the trees are packed in the proper packing material
in much the same manner as described for the crates. Regard-
less of the type of package, the packing must be done carefully
to avoid drying out of the trees while in transit. For local
shipments, shingletoe is commonly used around the roots but
trees to be shipped to distant points are usually packed in
sphagnum moss.
Top-Working
It is often desirable or necessary to top-work grove trees
because of cold damage or when it is desired to substitute a
new variety for an undesirable one. Top-working large trees,
while tedious, takes advantage of the root system already
present and brings a tree into production more quickly than
can be done by planting young trees. Frequently it is desired
to work over trees in yards so as to give additional varieties
for home use and this is sometimes done by grafting or budding
more than one variety on the same tree. Common methods for
top-working trees are: Budding sprouts or shoots resulting from
cutting back, budding old branches and then cutting them back,
bark grafting or cleft grafting. The method used almost ex-
clusively in this state is the budding of new shoots, some of the
work being done on the shoots produced when trees are "hat-
racked" and some on sprouts from the rootstock produced when
trees are cut off at the bud union.
The budding of rootstock sprouts will be necessary when
budded trees are killed to the bud by cold and the rebuilding of
the orchard depends on the rootstock sending up sprouts which
can be budded. In top-working relatively young trees this pro-
cedure is often more convenient and efficient than reworking
the tops, since there are no trunks and limbs left to produce
sprouts of the original variety and relatively little time is lost.
Moreover, in the case of tangerines which have brittle wood
and a tendency to split in the limb crotches and Temple oranges
which are dwarf in habit and also have brittle wood, the use
of top-working on a framework is of doubtful value, both due







Citrus Propagation 31

to the effect of the old top on the new top and also due to the
danger of breaking up the framework after a heavy top of grape-
fruit or orange is developed on it. Even old trees of tangerine
or Temple are commonly worked over to other varieties by cut-
ting back to the bud union.


Fig. 18.-Budded sprouts from the rootstock of a tree which was cut off
at the ground. This is one method of top-working.







Florida Cooperative Extension


The procedure for working over young trees (six years old
or less) by this method is to cut the tree off smoothly at or just
below the bud union. It is usually desirable to start the cut
on the side toward which it is desired to have the tree fall,
cutting about a fourth to a third through and then finishing it
off with a cut from the other side so as to avoid excessive split-
ting of the stump. The stump is then dressed to a smooth cut
and it is desirable to cover it with a good wound dressing. The
sprouts that come up are thinned to a suitable number arising
close to the stump. On a very small tree one sprout can be left,
but on stumps more than two inches in diameter leave two or
more, according to the size of the stump. Enough sprouts should
be left so that the stump will ultimately heal over well and
several sprouts also tend to grow together at the base and
support each other. After the sprouts have hardened up they
can be budded, using the procedure for nursery stock, but the
work of budding should not be done too soon. After the buds
have started they will have to be staked and trained. A nice
piece of work of this type can be seen in Fig. 18.


Fig. 19.-Tree partially cut through, felled and staked so as to support
root system while sprouts are being worked.







Citrus Propagation


Frequently it is desirable to work large tangerines in this
way on account of the possible danger of splitting of the frame-
work later. In such cases the shock to the root system when
a large top is suddenly removed is extremely severe and may
result in considerable damage. A better, but slightly more
laborious system, is to cut the stump about 2 through and
tip the tree over, leaving it attached to the stump (Fig. 19).
The top may be held in place by fastening it to a large stake
and this will prevent the top from being rolled around by heavy
winds. The sprouts that come up on the cut side are properly
thinned and budded in the usual way and after they are firmly
established the cut is finished and the top removed. After
this is done, another sprout or two may be worked at the point
where the final cut was made in order to round up the new top
and to help the process of callousing over the old stump. In
acreage to be handled in this way the trees of adjoining rows
can be felled toward each other and one stake used for two
trees and the alternate middles kept clear while the first sprouts
are being budded and started. The old tops will produce some
fruit during the period while they are left attached to the tree.
Trees budded on Poncirus trifoliata should not be cut off at
the bud, since this rootstock will frequently fail to send up
sprouts. Other common rootstocks usually send up sprouts
quite readily.
The common method of top-working old trees is to cut them
back to a framework, commonly called "hatracking," and then
to bud the sprouts which start on the limbs. On large trees
it is common to cut back to a point where the cuts are through
the limbs about three inches or more in diameter but the exact
point has to be determined by the wishes of the operator. The
larger the framework left the more buds will have to be put
in and the more old framework present which will have to be
kept free of sprouts after the new top develops. On the other
hand, the more limbs left the shorter the time necessary to get
a new top on the tree. To keep down the amount of budding
necessary and also to reduce the work of keeping the framework
free of sprouts later, the cuts are usually made in large wood
so as to leave four to seven large stubs and some time is sacri-
ficed in getting the tree back into production (Fig. 20).
To reduce the shock to the root system, an excellent practice
is to cut back about half the limbs and to work these over
and get the buds well started before cutting back the rest of







Florida Cooperative Extension


the limbs. In doing this, it is best to cut a large limb on one
side to permit access to the middle of the tree and then to cut
off the central limbs (Fig. 21). After these have been worked
to the new variety and a good top started (one to two years)
the remainder of the old top can be cut back and worked with-
out danger of breaking up the new top while removing the limbs.
This procedure is not usually followed, as the grower is anxious
to get the new top into production and considers it too much
delay. It has the advantage, however, of keeping the root
system in better condition and producing some fruit during
the period while the new top is being developed. While this
method is very seldom used, its advantages are such that it
recommends itself highly as a general method of top-working.


Fig. 20.-Large tree severely cut back preparatory to top-working.
Sprouts protected by burlap shade.







Citrus Propagation


In cutting back to a framework for top-working, the same
general rules hold as for cutting back to the bud. Large limbs
should be cut partially through on the side toward which they
are to fall and the cut finished on the other side, as this prevents
splitting. An alternative is to cut the limb off one to three feet
above the point where the final cut is to be made and then to
make the final cut at the proper point. The cut surface should
be smoothed over and painted with grafting wax or a good
wound dressing. The exposed framework and trunk should be
painted with whitewash to protect it from the sun, otherwise
the bark will be killed on the tops of the limbs. In addition,
some growers protect the framework and the new sprouts with
some sort of shade. This is usually a piece of sacking supported
on some sticks tied to the framework (Fig. 20).
Whitewashes which will stay on a tree trunk or limb in this
climate are difficult to make. Formulae for several durable
whitewashes may be obtained from the Florida Agricultural
Experiment Station at Gainesville or from the United States
Department of Agriculture. A very good formula is as follows:
Q uicklim e ............... .................... ... 50 lbs.
W ater ...................................... .... .... 10 gals.
Salt ............. ......... ..... ................... 4% lbs.

Slake the lime with water in such a way as to prevent burn-
ing of the lime and then add the salt. This may be diluted to
a suitable consistency for application. If it is to be used in a
sprayer it will have to be strained and diluted more than would
be necessary for brush application. It has been found that 3
to 5 pounds of zinc sulfate may be substituted for the salt
with better results. Dissolve the zinc sulfate first in water
and use this in diluting the slaked lime.
The limbs will sprout freely and after the sprouts have hard-
ened up they can be budded by following the same procedure
as for nursery stock. Not all of the sprouts should be budded
and some thinning will have to be done. Always bud some
sprouts near the cut end of the branch so that they will aid in
healing the cut surface, and other sprouts can be budded along
the limbs, selecting such as will help in forming a well-shaped
head on the new tree. After the buds have started the unused
sprouts can be thinned.
Some difficulty may be experienced if the buds are put in
before the sprouts have hardened up sufficiently. The large
root system tends to push the growth vigorously and the buds







Florida Cooperative Extension


may be easily "drowned" if the wood is too soft. Generally,
it is safer to lop the top of the sprout after the bud has taken
and to make the final cut later. It is also good practice to snip
off the tip of the sprout at the time the bud is put in. After
the buds have started it will usually be necessary to provide
some support to keep them from being broken off.
When trees are cut back it is common to have the new growth
develop "frenching." If any signs of frenching appear, it is
wise to spray the trees with the usual zinc spray recommended
for this purpose. Proper formulae for this purpose should be
obtained from current spray programs.
A number of other methods can be used in top-working, but
budding is generally preferred on account of the fact that a
great many workers can do good budding but very few are
familiar with the methods of grafting adaptable to citrus. These
other methods are useful at times and for this reason a discus-
sion of them will be given here.
When working large limbs, budding can be used directly on
the limb if the workman is careful. In case the bark is reason-


Fig. 21.-Large


tree partially cut back preparatory to top-working in
two stages.







Citrus Propagation


ably soft and pliable, some form of shield budding can be used
as previously described. Often the curved or angled incision
will be found superior to the "T" for this purpose. When the
bark is thick and will not "work" without splitting, it can be
shaved and scraped to remove the outer hard layers and the
inner bark left for "working." If the buds are slow to "take,"
a partial girdling of the limb above the bud or cutting back the
top of the branch will help. This sort of budding is difficult
and not recommended for ordinary use.











L L "





o .... ...








Fig. 22.-Bark grafting. A, scions in place; a brad driven through
the scion into the trunk will help to hold the scion in place. B, bark graft
taped and ready to be waxed.

Grafting
Bark grafting is occasionally used in working over stumps
and large limbs. Its chief difficulty lies in a mechanical weak-
ness of the union that may continue for some years. Like







Florida Cooperative Extension


cleft grafting, it gains a year of time on sprout budding. For
this type of grafting the stump or limb is cue off at a right
angle to the axis and the cut surface smoothed up with a knife.
Small scions up to six or eight inches long are given a long
slanting cut at the butt end and the sharp end shoved under
the bark with the cut surface facing the wood of the stump
(Fig. 22-A). Wherever possible a concave place in the contour
of the stump should be used. If the bark is at all pliable the
scion can usually be shoved under the bark easily, but where
the bark is hard it may be necessary to make a short downward
cut through the bark with the knife and to open the bark a
little at the top before the scion is inserted. A brad or small
nail may be used to help hold the scion in place. The stump is
taped around so as to hold the scions firmly in place and the
cut surface of the stump covered with paraffin or grafting wax
(see accompanying box) to exclude air (Fig. 22-B). Several
scions can be inserted, the number depending upon the size
of the stump. This method is very convenient for working
seedlings that have grown too long in the nursery and young
trees that have been frozen to the ground. The new growth
should be staked and saved from too much mechanical stress
until a strong union is established.
Cleft grafting is a standard method of top-working for many
types of trees and the results are excellent, but the work is slow
and tedious by comparison with other methods of working citrus.
It has one advantage in that the work can be done when the
bark will not "slip." For this work a grafting iron is needed
with which to split the stub of the limb or trunk (Fig. 23-A
and B). The cut is made squarely across and smoothed up as
for bark grafting. It is then split longitudinally with the iron
and mallet. Orangewood does not always split smoothly and
in careful work it is desirable to make a cut through the bark
and into the wood on each side of the stub with a knife, giving
a smooth cut where the scion is to be inserted. This can easily
be done by placing the edge of the knife as in Fig. 23-A and
hitting it a sharp blow with a mallet. Care must be taken to
get the cuts on the opposite sides of the stub accurately in line
if two scions are to be used. The grafting knife is then placed
across the stub, lined up with the two initial cuts and the split-
ting is accomplished with the aid of the mallet (Fig. 23-B).
The split is then wedged open by the use of the wedge end of
the mallet or a wooden wedge cut for the purpose. The scions







Citrus Propagation


Grafting Wax
Hume gives the following formulae for grafting waxes:
(1) Resin, 6 pounds; beeswax, 2 pounds; linseed
oil, 1 pint.
(2) Resin, 4 pounds; beeswax, 2 pounds; tallow, 1
pound.
Directions for preparing them are briefly as follows:
Break the resin into small pieces, cut up the beeswax
and place the two together in a suitable iron pot. Pour
the linseed oil over them, or in case recipe No. 2 is used,
place the tallow on top. Set the pot over a slow fire and
allow the materials to melt. Afterward remove from
the fire, pour into cold water, grease the hands and pull
until it is light-colored.
If a liquid wax is desired, take 1 pound of resin and
2 ounces of tallow, melt them together and mix thor-
oughly. Remove from the fire, cool slightly and add
slowly 6 ounces alcohol and 1 ounce spirits turpentine.
Keep tightly corked in wide-mouthed bottle. Apply
with a brush.
Paraffin is very convenient to use instead of grafting
wax and a portable lamp or lantern is manufactured
which will keep a small pot of it in the melted condi-
tion. Paraffin is frequently of too low a melting point
for satisfactory use in the open in Florida. This diffi-
culty can be corrected by adding 3 percent to 5 percent
of carnauba wax to the paraffin. For application, the
paraffin should be just hot enough to keep it melted; if
too hot it will injure the tissues of the plant.



should be six or eight inches long and cut with a budding knife
to a long wedge at the butt end (Fig. 23-C). These wedges
should be slightly thicker on one side than on the other. The
scions are inserted in the split and the cambitm of the scion
and the cambium of the stock carefully placed together with
the wood of the scion against the wood of the stock. The thick
edge of the wedge should be the one lined up with the cambium,
as this will bring the pressure at the point where it is needed.
After the scions are in place the wedge is removed, the stub







40 Florida Cooperative Extension

taped and the cut end covered with grafting wax or paraffin
(Fig. 23-D).
This type of grafting gives the union a great deal of mechan-
ical strength from the start and on this account is sometimes


W,:


4


Fig. 23.-Cleft grafting. A, splitting the stub down the sides; this
gives a cut for insertion of scion. B, splitting the stub. C, inserting
scions. D, scions inserted and stub taped and ready for waxing.







Citrus Propagation


used in working over large trees. Frequently Ihe pressure ex-
erted on the scion will be so great in large stubs as to tend to
pinch the scion off. Where this is likely to happen, a wooden
wedge should be left in the split to help ease the pressure on
the scion.
Success in any of the methods of grafting lies in the careful
carrying out of certain basic principles. Once the cutting is
started, finish up as rapidly as possible so that the cut surface
will not dry out. Be sure that the cambium of the scion and
the cambium of the stock are held firmly in contact. Seal the
wound thoroughly with grafting wax or paraffin. Do the work
when the tree is in active growth; even cleft grafting is more
successful under these conditions. If these things are done
carefully the work will give good results.

Inarching
Difficulties sometimes develop that make it necessary to give
a tree a new root system. This need occasionally is the result
of an attempt to grow a variety on an uncongenial rootstock but
more often the result of foot rot or some other disease that
girdles or partially girdles the trunk. It is possible under such
circumstances to inarch seedlings or sprouts into the trunk and
thus save the tree. This work is sometimes difficult and is not
usually attempted unless the tree to be saved is valuable. Where
the root system is sound and of a desirable type and sprouts
can be induced to grow, these are to be preferred. Where this
is not possible, seedlings can be planted around the tree and
after they are established they can be inarched into the trunk.
Seedlings are hard to start under the shade of large trees and
require considerable nursing.
Where the trouble is not caused by a disease, as in the case
of an undesirable rootstock, the inarching should be done as
close to the ground as possible (Fig. 24-A), but where it is a
matter of saving a tree attacked by foot rot the work should
be done well above the lesion (Fig. 24-B). Foot rot is commonest
on old seedling trees and under such conditions sour orange
seedlings are to be preferred for inarching and sprouts from
the sweet orange root should not be used as they are susceptible
to the disease. If the tree to be inarched is headed low, the
seedlings may be worked into the limbs instead of the trunk
but it will be desirable to trim the trees up as much as possible
to let light into the seedling while it is becoming established.







Florida Cooperative Extension


Fig. 24.-Trees saved by inarching. A, Temple orange tree on rough
lemon root inarched with Cleopatra mandarin; the inarch at left was close
to the ground and of a fine type; fruit borne on limbs above the inarch
showed favorable influence of new root system. B, old seedling orange
tree attacked by foot rot successfully inarched with sour orange.

Inarching is accomplished by making an inverted "T" inci-
sion in the trunk of the tree and opening the flaps of bark
slightly with the wedge on the budding knife. The sprout or
seedling is then cut with a long slanting cut at such a height
that when it is inserted into the "T" slot the cut surface will
be entirely within the bark and in contact with the wood of the
trunk. The insertion is made by "springing" the stem of the
seedling or sprout sufficiently so that the tip can be inserted
under the flaps of bark and when the stem is straightened the
tip will come to the proper position. As the stock tends to
spring away from the trunk of the tree it is necessary in most
instances to secure it to the tree with a small nail or brad. This
should be driven in so that the cut surface of the stock and
wood of the tree trunk are held tightly together. The whole is
then wrapped with budding tape, raffia or string to help hold
it in place and the wound sealed with grafting wax or paraffin
(Fig. 25).







Citrus Propagation


A slight variation of the above has been used with some
success in South America in the last few years. The seedlings
are grown in a nursery and the inarching is done at the same
time the seedling is set under the tree instead of after it has
become established. The hole for the roots of the seedling is
dug, the inverted "T" slot cut in the bark of the large tree
and the stem of the seedling is cut with the long slanting cut
and at such a height that, when inserted and bradded in the
"T" slot, the roots are in the proper position in the hole. The
dirt is then filled in around the roots and watered thoroughly
and the seedling kept well watered thereafter. Seedlings may
be handled either bare rooted or balled, but great care must
be used to keep them well watered until established. This
method has the advantage of having the roots free while the
trunk of the seedling is being inserted into the "T" slot in the
trunk of the nurse tree and if the inarch "takes" some time is
saved. Good results have been obtained where great care was
used in caring for the seedling, otherwise results have been
variable. A grower who wishes to use this method should try
it out before using it extensively.













I A


Fig. 25.-Inarching. A, seedling inserted in inverted "T" slot and bradded.
B, inarch tied and paraffined.
The work will have to be done when the bark will slip and
even then more or less difficulty will be experienced in working
the bark. Scraping or shaving the bark to make it more pliable
will help somewhat. If the work is done carefully and the







Florida Cooperative Extension


wound thoroughly sealed, it will usually "take" and after sev-
eral weeks the wraps can be cut but the seal of wax or paraffin
should not be disturbed.
Variations of the above method have been employed but in
general most of these cause the wood of the stock and the wood


Fig. 26.-Inarched seedling put in at an angle to the axis of trunk, a
procedure that is not recommended.







Citrus Propagation


of the trunk or limbs to be at a sharp angle to each other
(Fig. 26), and results do not seem to be as good as with the
above method. Observations indicate that best results are
obtained where the stock and trunk are nearly parallel. This
may be the result of a more natural flow of sap in such unions.

Rooting of Cuttings
The rooting of cuttings as a method of citrus propagation
has been chiefly a matter of scientific interest in this country


































Fig. 27.-Plants produced from rough lemon cutting (left) and seedling
rough lemon of same age (one year). (Courtesy J. H. Jefferies.)





























Fig. 28.-Plant produced by rooting a leaf of rough lemon.


































Fig. 28.-Plant produced by rooting a leaf of rough lemon.







Citrus Propagation


but it is reported that some groves have been produced by this
method in South Africa. While all varieties of citrus can
probably be rooted with proper equipment and care, lemon and
particularly cuttings of rough lemon root more readily than
other varieties tried. Figure 27 shows a plant of rough lemon
produced by rooting a cutting as compared with a seedling.
In Fig. 28 is shown a small rough lemon plant produced by
placing a leaf with only the petiole attached to it in the cut-
ting box.
In propagating citrus by cuttings, some sort of bottom heat
is required in the cutting box and the atmosphere surrounding
the cuttings should be very moist. An electrically heated cut-
ting bed, such as is illustrated in Fig. 29, is very useful for
this work. It will be found desirable to leave part of the leaves
on the cuttings when they are placed in the bed. Considerable
time is required for the development of a root system.












w rr. -. a rsa

Fig. 29.-Electrically heated cutting bed (see Annual Report of the Florida
Agricultural Exp. Sta. for 1928, pp. 57-59).

A modification of the rooting of cuttings is sometimes used
in producing a new root system on old trees that are almost
girdled by foot rot or other trouble. A frame about 8 or 10
feet square and a foot or more high is built around the base
of the tree and filled in with clay or a soil containing a large
percentage of clay. This soil should be kept moist during dry
weather. If the tree is still vigorous it will in time put out
roots above the girdle and eventually develop a new root system
sufficient to support the tree. This same system can be used
in putting a tree on its own root if the rootstock on which it
is budded is not congenial. In doing this the trunk is partially







Florida Cooperative Extension


girdled at the bud union and soil is packed around it until a new
root system forms. Fig. 30 shows a small tree treated in this
way with the resultant development of a root system.
Good sized roots of most species of citrus if cut off and the
cut end pulled to the surface of the soil will start a top and
occasionally trees are produced in this way. This procedure
has had no commercial application but may be used under special
conditions.

Transplanting Large Citrus Trees
The moving of large trees has become increasingly popular
during the last few years and considerable acreage has been
planted in this way. When
done on a considerable scale,
operators advise that they




















Fig. 30.-Young tree put on its Fig. 31.-Severing tap root after
own roots by being girdled. and all lateral roots have been cut. White-
having soil packed around the wash has been applied as soon as the
trunk. (Courtesy J. H. Jefferies.) tree was cut back.

can transplant 10- to 15-year-old trees at from $1.00 to $1.50
per tree. While it involves considerable work, the large trees
will come into bearing much sooner than young trees. Gen-
erally, however, the transplanting of large trees is limited to
replacements in groves and for yard plantings.







Citrus Propagation


Large citrus trees can be transplanted very easily if the proper
precautions are taken, and there is practically no danger of
failure. The amount of root system to be transplanted will
depend upon the facilities for moving the trees and the trees
should be dug with as little damage to the root system as pos-
sible. As soon as the tree is dug the roots should be protected
from drying out by
wet burlap or other
covering and kept
protected until plant-
ed. The new hole
should be large
enough to contain the
root system easily
and should be dug .
just before the tree -
is planted so that it
will not have a chance- ---
to dry out. If pos-
sible, the surface soil
and subsoil should be
kept separate and
some well decom-
posed compost and
ground steamed bone
meal should be added
to the soil as the tree
is planted. Injured
roots should be
pruned off. The soil
should be placed Fig. 32.-Tree being lifted by means of
about the roots so as wrecking crane. If the tree is to be moved
any distance the roots should be wet down and
to leave them in nor- covered with a tarpaulin.
mal position and not
bunched up. Water should be added as the soil is filled in;
the soil should be made firm about the roots and a heavy final
watering given. The tree should be given plenty of water until
it is thoroughly established.
Methods of digging trees vary considerably, but the following
method has been found very convenient. After topping the tree
dig a trench around it 18 to 24 inches deep, depending on the
size of the tree, cutting all lateral roots (Fig. 31). From some







Florida Cooperative Extension


point in the trench dig deeply under the tree to cut the taproot
at a level two feet or more below the bottom of the trench.
Then, by using a crane or by hand, loosen the tree so that it
can be lifted from the hole (Fig. 32). The new hole is excavated
evenly to the depth of the trench used in removing the tree
and a post hole digger or shovel is used to make a hole in the
center of it for the taproot. When the tree is let down into
this hole the lower lateral roots will rest on undisturbed soil
so that there will be less tendency for the tree to settle later
(Fig. 33). There is also less disturbance of the subsoil than in
the ordinary methods of excavation.
Trees can be moved during the winter when they are fairly
dormant, in which case care will have to be used in keeping
them watered during the dry spring weather. Trees can also
be moved at the beginning of the summer rainy season and will
usually become established by winter.


Fig. 33.-Water being used to wash soil around the roots and thus
avoid air pockets. The use of plenty of water greatly enhances the
possibility of the tree surviving.







Citrus Propagation


The amount that the top will have to be cut back will depend
upon the extent of the root system moved and the care taken
in moving. If only a comparatively small root system is moved
it is well to cut the top back to a framework and protect the
limbs from sunburning with whitewash. It is best to white-
wash before cutting back and retouch it after moving, since
sunburning can take place in a very short time. Where large
root systems are moved, less cutting back of the limbs will be
required. Trees have been moved under favorable conditions
without cutting back of any kind but the cost is too great for
this to be generally practical.
Where it is desired to move large numbers of trees an auto-
mobile wrecking crane mounted on a truck is very convenient
or a simpler crane may be devised that can be attached to the
ordinary truck. The arm of the crane can be attached to the
trunk of the tree, with the bark protected by padding. As soon
as the digging is completed, the tree can be lifted and a tarpaulin
or large burlap covering wrapped around the roots and the tree
moved quickly to the new location. It is easy to back the truck
up to the new hole and let the tree down and hold it at the
proper level while the dirt is being filled in.