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Group Title: Bulletin
Title: Dooryard citrus plantings in Florida
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00094960/00001
 Material Information
Title: Dooryard citrus plantings in Florida
Series Title: Bulletin - Florida Agricultural Extension Service ; 140
Physical Description: 22 p. : ill ; 23 cm.
Language: English
Creator: Granger, John A.
Florida -- Dept. of Agriculture
University of Florida -- Agricultural Extension Service
Donor: unknown ( endowment ) ( endowment )
Publisher: Agricultural Extension Service, University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 1949
Copyright Date: 1949
Subject: Citrus -- Propagation -- Florida   ( lcsh )
Ornamental horticulture -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
General Note: "August, 1949."
General Note: Cover title.
General Note: At head of title: Cooperative extension work in agriculture and home economics ... Agricultural Extension Service, University of Florida, Florida State University and United State Department of Agriculture cooperating.
Statement of Responsibility: by John A. Granger.
 Record Information
Bibliographic ID: UF00094960
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 84299025

Table of Contents
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Full Text

Bulletin 140

August, 1949

(Acts of May 8 and June 30, 1914)

Dooryard Citrus Plantings

in Florida

Horticulturist, Florida Agricultural Experiment Station

Fig. 1.-Foundation planting using an orange tree as a corner accent plant.


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


J. HILLIS MILLER, Ph.D., President of the University'
H. G. CLAYTON, M.S.A., Director of Extension
MARSHALL O. WATKINS, M.Agr., Assistant to the Director

Agricultural Demonstration Work, Gainesville
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.Agr., Poultry Husbandman'
0. F. GOEN, D.V.M., Assistant Animal Husbandman
F. S. PERRY, B.S.A., District Agent
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., Agriculturist
V. L. JOHNSON, Rodent Control Specialist'
F. S. JAMISON, Ph.D., Vegetable Crop Specialist'
STANLEY E. ROSENBERGER, M. Agr., Asst. Veg. Crop Specialist

Home Demonstration Work, Tallahassee
MARY E. KEOWN, M.S., State Agent
ETHYL HOLLOWAY, B.S., District Agent
MRS. EDYTH Y. BARRUS, B.S.H.E., District Agent
ANNA MAE SIKES, M.S., Specialist in Nutrition
JOYCE BEVIS, A. M., 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
LORENE STEVENS, B.S., 4-H Club Specialist for Girls

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

SCooperative, other divisions, U. of F.
SIn cooperation with U. S.

Dooryard Citrus Plantings in Florida

Page Page
INTRODUCTION ----..----- 3 CITRUS STOCKS ---_.. -.._ 12
SELECTION OF VARIETIES .------- 4 YOUNG TREES -- --------- 13
Grapefruit ---- 9 Fertilization -- 14
Mandarins 9 Culture _.-----_--..-- ..------ 20
Limes and Lemons 10 Pruning -_- 20
Miscellaneous Fruits ---.---- 11 Pest Control -- 21

Citrus trees are a must in dooryard plantings in Florida.
Properly handled, they can be both beautiful and useful. But
too often their effectiveness is ruined by the application of fer-
tilizers or sprays which are desirable for other plants but not
adapted to citrus. Since such plantings mixed with other orna-
mentals entail many problems not common to commercial citrus
production this bulletin has been prepared to cover the particular
problems that are likely to arise.

Purpose of Planting
Dooryard citrus trees may be planted solely as a source of
fruit, for ornamentation or for a combination of the two. The
purpose of the planting should be kept clearly in mind if a satis-
factory planting is to be made. Since citrus trees are very
ornamental when properly handled, a combination of the two
purposes is very desirable and the planting can be made to blend
with the overall landscape plan of the yard and also produce an
abundance of good citrus fruit. With a good planting plan and
proper selection of varieties it is possible to have fruit most of
the year.
When citrus trees are being used primarily to enhance the
ornamental landscape plan, it is possible to use many plants be-
longing to the citrus family which do not necessarily produce
desirable fruit for home use. There are citrus relatives that
lend themselves particularly well as shade trees, hedge plant-
ings, backgrounds, free standing specimens, and framing plants.
Severinia buxifolia Ten. is a citrus relative which is particularly
good as a hedge plant because of its dense, glossy, dark green
foliage and its slow growth habit. It is also valuable in small
group plantings at accent points. Orange-jessamine, or Chalcas

4 Florida Cooperative Extension Service

exotica Millsp., is worthy of planting in backgrounds and framing
locations because of its fragrant white flowers and attractive
clusters of small berries. It may be trimmed to a formal shape
or trimmed loosely to develop an informal effect. Trifoliate or-
ange (Poncirus trifoliata Raf.) is good for planting when a dense,
thorny hedge is desired.
When citrus trees are used for both ornamentation and fruit
careful thought should be given to the selection of varieties that
will fit into the landscape plan as well as supply fresh citrus
fruit for most of the year.

Selection of Varieties
For the average family a good planting would include at
least one early, one midseason, and two late varieties of oranges,

Fig. 2.-Specimen grapefruit tree on lawn.
M "

Dooryard Citrus Plantings in Florida

while two grapefruit trees should provide sufficient grapefruit.
Additional trees of some of the less common varieties of citrus
may be added to suit the desire of each individual home owner.
It is desirable to have as much spread in the ripening season as
possible. Fruit quality, type of soil, available space, personal
preference, and ripening season must be considered when choos-
ing varieties.
Early oranges include Parson Brown, Hamlin, Orlando, and
Navels. Midseason varieties include Pineapple, Jaffa, and Temple.
Valencia is the leading late variety.
Parson Brown is a widely grown early orange with fruit that
ripens in October and November, but is easily held on the tree
through January if the tree is properly fertilized and mineral
deficiencies are eliminated. The fruit is of excellent quality with
a rich orange color, nearly spherical in shape, with 10 to 19 seed
per fruit. A vigorous upright grower, it can be used in lawn

Fig. 3.-Orange-Jessamine used as accent plants on corners of porch
in foundation planting.

Florida Cooperative Extension Service

areas when space is at a premium. This variety will grow well
on all standard rootstocks.
Hamlin, a newer variety, has been widely planted in recent
years because of its early maturing and usually seedless fruit.
Usually mature in October and November, the fruit can be held
through January with proper management. When grown with
strict adherence to standard fertilizer practice, quality is very
good, but the pulp tends to dry out when the tree is too vege-
tative as a result of too much fertilizer. The fruit has a smooth
textured, very thin skin. Mostly seedless, occasional fruits con-
tain up to five seeds. The tree is somewhat upright in growth
habit, but not as large as the Parson Brown. It is a vigorous
grower on most of the common stocks. Growers of this variety
have complained of excessive fruit splitting, but this is usually
associated with the use of high nitrogen fertilizer without suf-
ficent copper.
Orlando, commonly classified as an early orange, is in reality
a hybrid of Bowen grapefruit pollinated with the Dancy tanger-
ine. The fruit is flat like a mandarin with a very smooth, highly
colored skin of delicate texture. It ripens very early, along with
the Parson Brown and Hamlin, but has a shorter season. The
tree is not too vigorous and tends to dwarf. Budwood of this
variety became infected with a virus that caused heavy mor-

Fig. 4.-Severinia buxifolia hedge.

., . ._ .. _- ., r. :. .._

Dooryard Citrus Plantings in Florida

tality in some plantings and trees of this variety should not be
purchased unless the source of the budwood is known to be

Fig. 5.-Calamondin used as a corner accent plant.

Florida Cooperative Extension Service

The Washington Navel has never been a satisfactory com-
mercial crop in Florida, though in occasional years it will pro-
duce fruit of excellent quality. The fruit tends to dry out some
seasons even before maturing and other years it has been a
shy bearer. The fruit is elongated and somewhat tapering to-
ward the stylar end, terminating in an umbilicus, and is seedless.
It ripens from October to December. The climate of Florida is
not considered to be as suitable for this variety as the drier pro-
ducing areas. There are a few new strains of navels now avail-
able at citrus nurseries that show promise and for those who
particularly want a navel orange they will probably be more
satisfactory than the Washington. The tree is rather large and
spreading in nature of growth and is very vigorous.
The Pineapple is the most common midseason orange vari-
ety. The fruit is medium in size, ripens in December and Janu-
ary, and is of excellent eating quality. The number of seed
varies from 13 to 23 and this is the only objection to this variety.
The tree-which grows large-is rather low-headed and spread-
ing in growth habit in comparison with other varieties of or-
anges. It grows well on common stock, but will tend to set
alternate crops of fruit if the fertilizer program is deficient.
Jaffa is another midseason variety that produces oranges
of excellent quality with only six to nine seeds. The fruit is
rounded-oblate in shape, smooth in texture, with normal sweet-
ness. The tree is vigorous, grows large and has a rather up-
right growth habit. This variety is more resistant to cold than
are some of the other varieties of oranges.
Temple is probably a natural hybrid between the mandarin
and sweet orange. The fruit is deep orange to reddish in color;
with a slightly pebbled peel; oblate to spherical in shape; and
medium in size. The fruit matures from December to March,
and is considered one of the best oranges to eat from the hand,
since it peels easily and the quality is excellent. There are usu-
ally about 20 seeds. The tree makes a rather low-headed and
bushy top and is smaller than other varieties of oranges. It is
more sensitive to cold than ordinary oranges and grapefruit, but
wherever it can be grown it is very desirable. It can be grown
on most of the common stocks, but the fruit quality is better
when grown on sour orange or Cleopatra mandarin stock.

Dooryard Citrus Plantings in Florida

Valencia is the most popular late variety. The fruit is of
excellent quality, rather oblong in shape and seldom contains
more than six seeds. Its season is from March to July or August.
The tree is vigorous, tending to be rather tall and cylindrical, and
grows well on most common stocks. This variety is somewhat
variable and a number of strains are recognized. It has been
propagated under several names such as Valencia Late, Hart's
Late and Hart's Tardiff. Lue Gim Gong, while originally report-
ed to be a hybrid, is probably a strain of Valencia.

The ordinary seedy white grapefruit varieties are not easily
distinguishable and there is no clear difference in ripening period,
but Duncan and McCarty are recognized as two outstanding va-
rieties. McCarty produces a large fruit which will hold longer
on the tree without the seed sprouting than most other seedy
varieties. Fruit of both varieties have 30 to 60 seed and excel
in flavor. The trees are very large and spreading, with a long
life and great vigor. They can be grown on any of the common
The Marsh grapefruit is often referred to as white seedless
grapefruit, but it usually has two to eight seeds when grown in
Florida. The fruit is of very good quality and for those people
who dislike removing seed from the fruit, this variety is highly
recommended. The trees are very large and spreading-even
larger than the seedy varieties. They are easily grown on a
variety of common stocks and are heavy producers.
Pink grapefruit includes the Foster, which is very seedy, the
Thompson or Pink Marsh Seedless, and the Ruby which is also
seedless. The Ruby is highly colored with a pronounced blush of
color showing through the peel. These varieties have growth
habits similar to other grapefruit trees and have increased in
popularity on account of their color appeal. These varieties can
be grown on the common stocks.

The Dancy tangerine is the most popular of the mandarin
group and is usually accepted as the standard commercial tan-
gerine. The fruit ripens from November to February and is of


Florida Cooperative Extension Service

excellent quality, with usually 6 to 20 seeds. The fruit will dry
out and become pithy if held on the tree too long. This condition
can be aggravated by fertilizing too heavily. The trees are rather
large and less bushy than most mandarin trees. They have a
tendency to set very heavy crops some years and the branches
may break from the weight of the fruit. They can be grown
on most of the common stocks.
The term Satsuma covers a group of similar mandarins that
ripen early in October or November. The quality of the fruit is
not as good as other mandarins. The fruit resembles a tangerine
in appearance and size and is generally seedless, but may contain
one to five seeds. The tree has a dwarfed, low-headed, bushy
type of growth and does exceptionally well when propagated on
trifoliate rootstock (Poncirus trifoliata). This variety is used
extensively in the northern part of the state because it has more
cold resistance than other varieties of edible citrus.
The King orange is a late-maturing mandarin that ripens in
March and April. The quality of the fruit is excellent even
though it is rather tough and usually contains 18 to 20 large
seed. The tree has an irregular upright growth habit with fre-
quent thorns. This growth habit causes many of the fruits to
be exposed to too much sunlight and become sunburned. This
variety is not considered very satisfactory from a commercial
standpoint, but the fruit is received well in the fancy fruit mar-
ket. It may be propagated on the common stocks.

Limes and Lemons
The Tahiti or Persian lime is the most popular lime in Flor-
ida. It usually matures fruit in late spring, but will mature
some fruit during the entire year if the temperature does not
get low enough to damage the tree or check its growth. The
fruit is oval to elliptical in shape with a smooth skin with a light
green to yellow color and almost always seedless. The quality
of the fruit is very good, the juice having a high acid content and
good flavor. The tree has a low-spreading growth habit, attain-
ing a height of from 10 to 15 feet. It is a vigorous grower on
most common stocks, but is grown in Florida primarily on rough
lemon stock. This variety will not withstand very severe winters
north of central Florida and is mainly limited to the south central
and southern parts of the state.

Dooryard Citrus Plantings in Florida

The trees are susceptible to gum diseases that may be caused
by either of two fungi, Diplodia or Phomopsis. These fungi
cause considerable loss of trees, especially after 8 or 10 years
of age. One method of eliminating some of these troubles would
be to bud a grapefruit seedling stock about three years old with
the scion of the Persian lime. This has been found satisfactory
for dooryard plantings.
The Key lime is a small fruit; round in shape with a very
smooth peel and a light yellow color. It matures in late fall to
spring, with some fruit maturing the year around. The juice is
very acid with a typical lime flavor and the fruit usually has four
to eight seeds. The tree is small, bushy, and spreading in
growth habit, with a thin willowy appearance. This variety is
too tender to thrive in most locations on the mainland of Florida.
It is grown mostly on the Keys below Miami and off the West
Coast in the vicinity of Ft. Myers. This lime is grown through-
out the Caribbean area and sold commercially under several
names such as Mexican limes, West Indian limes, and Dominican
The Villafranca lemon is a medium sized lemon of excellent
quality and flavor, with only a few seeds, seldom over six. The
tree is large, spreading, and open in growth habit. This variety
was introduced into Florida in 1875 by General Sanford but has
not become an important commercial variety because it is suscep-
tible to various trunk diseases which cause heavy losses.
The Meyer lemon matures from December to April, with
some fruit maturing more or less throughout the year. It is a
large fruit with less acid than most commercial lemons, but with
abundant juice and only about 8 to 12 seeds. The quality of this
variety is very good for dooryard plantings, but it is too thin-
skinned, tender, and low in acid for commercial plantings. It is
especially valuable for locations that are too cold for other
lemons, since it has about the same cold resistance as common
sweet oranges. It grows well on rough lemon or sweet orange
stock and is not subject to the trunk diseases which plague most
limes and lemons in Florida.
Miscellaneous Fruits
Many home owners may desire to grow some of the varieties
that are not so common commercially.

Florida Cooperative Extension Service

The tangelos are a group of hybrids that are the result of
crossing tangerines with grapefruit and the term is sometimes
used popularly to include crosses between oranges and man-
darins. The early crosses were so susceptible to lemon scab as
to make them difficult to grow and were largely discarded. The
two best known varieties of this type were Thornton and Samp-
son. Later selections were much more resistant to scab and can
be grown without excessive spraying. The best known of these
are the Seminole, Yalaha, and Mineola, and are recommended for
yard planting.
The calamondin is used largely as an ornamental. It pro-
duces a small, very sour fruit that has the appearance of a very
small, highly colored tangerine. The juice is good when used
as a substitute for lime juice and an excellent preserve can be
made from the fruit. The tree grows rather upright and tall, and
is useful in landscape plans as accent, specimen, or border plants.
The kumquats are used mostly for decorating fancy gift
boxes of citrus and as a fruit for conserve. There are several
varieties of kumquats, but Nagami and Marumi are most com-
monly planted in Florida. Nagami fruit is oblong, with a smooth
rind and acid juice. The ripening season is from October to
January and the fruit contains two to five seeds. The tree is
dwarf, bushy, and very vigorous. It can be grown on common
stocks. Marumi fruit is round and matures at about the same
time as the Nagami; the tree has a very round, dense top which
is adapted to driveway plantings. Kumquat trees attain a height
and spread of from 8 to 12 feet when mature, and are very de-
sirable for roadside plantings and garden use.
There are many additional groups of citrus and miscellane-
ous varieties which will prove interesting in dooryard plantings,
and the reader is referred to "The Cultivation of Citrus Fruits"
by H. Harold Hume for a more complete listing. Among these
are the citron of commerce, the shaddocks or pomelos, the various
limequats, and the trifoliate orange (Poncirus trifoliata) which is
occasionally used to produce a thorny impenetrable hedge.
Citrus Stocks
The selection of a stock for citrus trees must be considered
in the light of the type of soil in which the trees are to be planted.
The most commonly used stock in Florida, the rough lemon, is

Dooryard Citrus Plantings in Florida

well adapted to light, well drained soils but will not grow well on
wet or poorly drained soils. Where the soil is suitable it produces
a very vigorous, fast-growing top and a heavy yield. Due to its
vigor it competes well with shrubbery. The quality of the fruit
produced by trees budded on this stock is inferior to that pro-
duced on trees budded on less vigorous stocks. On soils that oc-
casionally may become waterlogged, sour orange and Cleopatra
mandarin make better stocks and produce a superior quality
of fruit.
Planting and Care of Young Trees
After selecting varieties of citrus trees to include in the door-
yard planting, plans should be made to secure young trees when
they are most dormant. This usually occurs in January or early
February, but the second best planting season is in June at the
beginning of the summer rainy season. The soil should be
cleared and if it is known to be very acid, a light application of
dolomite limestone would be desirable. On soils known to be
alkaline, it is best not to add anything to aggravate that condi-
tion, for citrus grows best on a slightly acid soil.
Different varieties of citrus require different spacing, but
it is desirable to allow orange and grapefruit trees a space
equivalent to a 25 foot diameter circle, if possible. Calamondins,
kumquats, satsumas, limes and lemons do well if the space al-
lowed is roughly equivalent to a circle with a diameter of 15 feet.
Young trees should be purchased only from reputable nurseries
or dealers that will furnish freshly dug, healthy stock. A good
size to purchase for new plantings would be trees with a caliper
of 8/4 to 1" at the bud and the minimum should be 5/8". Do not
delay planting young trees after they are received from the
nursery, for they may dry out too much. If there should be any
delay after receiving the nursery stock, cover the roots with a
moist burlap sack or some material that will keep them from
drying out.
Set the trees in a hole that will allow the root system to
spread out fully without restrictions. The correct depth is as
high as or a little higher than they stood in the nursery row.
It is desirable to apply water when refilling the hole in order to
better settle the dirt around the roots to prevent the tree from
settling too deep later on. When steamed bone meal is available,

Florida Cooperative Extension Service

it should be applied with the dirt when refilling the hole at about
two pounds per tree, but raw bone meal should never be so used.
This will give a slowly available source of plant food to help
develop a good strong tree. After filling the hole, a small rim
of loose dirt may be made into a basin around the root area to
make watering more efficient. Do not allow young trees to dry
out at any time.
When young trees are planted in northern or north central
Florida before the danger of freezing temperatures has passed,
they should be banked with good clean soil without trash in it
to a height well above the bud union. This bank should be re-
moved as soon as danger of freezing has passed. This same
procedure should be practiced for two or three years until the
tree gains some size and is better able to stand freezing tem-
Bearing citrus trees can be transplanted readily if the proper
equipment is available. Instructions for this may be found in
Florida Agricultural Extension Bulletin 139 on citrus propagation.
Young trees can be fertilized with the same fertilizers rec-
ommended for bearing trees, as described later. One pound of
fertilizer should be used per tree three times a year and Febru-
ary, June and October would be satisfactory for applications.
One-fourth to 1/ pound of coarse granular bluestone (copper sul-
fate) should be applied per tree. Do not use the finely ground
bluestone, as it will be toxic to the tree.
Keep a careful check on young trees against salamanders
and gophers. A caterpillar known as the "orange dog" eats
leaves of young trees and should be picked off by hand. Scale
insects must be controlled to prevent severe damage. Young
trees should be cultivated frequently to control weeds and grasses
so the tree will not have to compete with them for moisture and
Management of Bearing Trees
The tendency of home owners is to over-fertilize dooryard
citrus trees and induce additional problems unnecessarily. The
following suggestions are made to be used as a guide for most
fertilizer problems. For average soil conditions in Florida the

Dooryard Citrus Plantings in Florida

following fertilizer formula will be found quite satisfactory for
citrus trees in dooryards:
N P205 KO MgO* MnO CuO
4 -- 6 -- 8 -- 4 -- 1 -- 1
The above mixture can be used for all applications through-
out the year. Three applications per year should be made at
about the following periods: January or February, May or June,
and October or November. Do not use excessively large applica-
tions because the citrus tree, in order to produce good quality
fruit in quantity, should not be excessively vegetative, but pref-
erably a little on the "hungry side" as compared to the type of
growth in shrubbery. It is difficult to give exact figures on the
size of the application but a fairly good rate is 1 pound of fer-
tilizer per application per year of age up to 10 years and after
that an additional 1/2 pound for each additional year of age. For
example, a 12-year-old tree would receive 11 pounds per applica-
The above recommendation is made for trees without lawn
grasses growing under them. Fertilizer should be applied to
entire root area which is usually slightly larger than the spread
of the top. Do not apply fertilizer to dry lawn grass under the
trees without first applying water. This will avoid severe burning
of the grass. Trees having heavy grass sod growing underneath
the spread of tree will need up to 50 percent additional fertilizer
to allow for that the grass will take up. Sometimes it may be
desirable to drill or punch numerous holes in lawn grasses and
apply the citrus fertilizer below the root level of the lawn grass.
For those trees that do not receive a copper spray for mel-
anose control, it may be necessary to apply coarse granular blue-
stone during the dormant season to control excessive fruit split-
ting. This should be applied at about 1 pound per tree for mature
trees and in heavy lawn areas it may be necessary to use 2 pounds
per tree on very large trees.
For trees located on alkaline soils in the coastal areas, an
additional 1 percent of manganese in the fertilizer or as a sep-
arate application of 1 pound of manganese sulfate per tree will
be necessary to control a chlorotic condition of foliage caused by

Florida Cooperative Extension Service

manganese and/or zinc deficiency in the soils. In some of these
locations it will be necessary to use a nutritional spray made up
as follows:

For Large
Spray Machines
W ater ......................................100 gallons
Basic copper sulfate or other neutral copper.. 2 pounds
Zinc sulfate (89 percent) .................... 3 pounds
Manganase sulfate (Agr. grade) .............. 3 pounds
Hydrated lime (spray grade) ................ 3 pounds
Wettable sulfur (if rust mite control
is desired) ................... ..... . 10 pounds

For Small
3 gallons
3 tablespoonfuls
2% tablespoonfuls
3% tablespoonfuls
61/ tablespoonfuls

18 tablespoonfuls

Some seed and fertilizer dealers can furnish prepared spray
mixtures of this type. For most effective results the spray
should be applied in the dormant season just before growth starts
or just after the blossom petals have fallen. These nutritional
sprays will need to be followed by an oil spray in June or July
to control scale insects that tend to build up as a result of the
residue left on the leaves.

Remember that ordinary lawn and shrubbery fertilizers
seldom contain more than nitrogen, phosphorus and potash and

Fig. 6.-Typical fruit on zinc-deficient trees (left) and fruit from zinc-
deficient tree one year after treatment with zinc spray (right).

Dooryard Citrus Plantings in Florida

citrus requires in addition, magnesium, manganese, copper, and
zinc for best growth. Citrus fertilizer could be used on lawns
and shrubbery for convenience when only one type of fertilizer
is to be purchased.
There are a number of indications of improper nutrition in
citrus trees that can be easily recognized and corrected. Some
of the most common reported from dooryard plantings are as
Fruit Splitting.-This is quite common when the trees are
deficient in copper, zinc, manganese, or magnesium but may be
brought on by over-fertilization with nitrogen and adverse
weather conditions such as excessive rains. When large amounts

Fig. 7.-Marl chlorosis on grapefruit. This pattern is a combination of the
patterns of zinc and manganese deficiencies, but is primarily the latter.

Florida Cooperative Extension Service

Fig. 8.-Defoliation of magnesium-deficient seedy grapefruit tree induced
by a heavy crop.

of nitrogen are used they must be offset by correspondingly high
applications of bluestone (copper sulfate), since copper is in
some way related to the utilization of nitrogen.
Insipid Taste.-This is commonly associated with dry or
pithy fruit with insufficient acid and usually can be corrected by
proper application of copper sulfate and a change to a suitable

Frenching.-This is caused by a zinc deficiency and is char-
acterized by irregular green bands along the midrib and main

Dooryard Citrus Plantings in Florida

veins on a background of light yellow to almost white. In very
acute cases the leaves will be very small, pointed and abnormally
narrow. The fruit borne on weak, frenched twigs is very small,
smooth, light colored and very insipid tasting, with a low juice
content. In some cases this may be corrected by applying 1 to
2 pounds of zinc sulfate to the soil around the tree, but more
often a zinc spray is required.
Bronzing.-This term is applied to the occurrence of yellow
foliage near the maturing fruit while the fruitless twigs bear
green leaves. This is caused by a deficiency of magnesium. It is
more noticeable among seedy varieties and in seasons of heavy
fruit production, and can be corrected by the use of magnesium-
bearing fertilizers.

Overall Yellow Foliage.-This usually indicates a lack of
nitrogen, but can be induced by too much soil moisture in poorly
drained locations. If the drainage proves to be satisfactory,
increase the fertilizer application.


Fig. 9-Angular, S-shaped growth typical of copper deficiency.

- 7

Florida Cooperative Extension Service

Boron Toxicity.-This is indicated by a pronounced yellow-
ing of the tips of the leaves which increases in area on the
individual leaf until half or more of the leaf surface is involved.
Dead areas frequently develop along the edge of the leaf near
the tip and leaves will shed rapidly. Several flushes of growth
may show this disturbance in acute cases. This condition is com-
monly induced by the use of soaps containing borax and the dump-
ing of wash water around the trees. It sometimes results from
the use of fertilizers containing too much borax.
Dieback.-This term is applied to a dying back of twigs that
are long, soft, angular, frequently "S" shaped, and more or less
drooping. The result of copper deficiency, it is the most common
trouble reported by owners of dooryard trees. This is due to
the fact that such trees usually receive excessive amounts of
nitrogen and no copper since, unlike trees in commercial groves,
yard trees are not usually sprayed with copper to control dis-
eases. Use soil applications of bluestone or copper sprays.

It is most important in Florida to build up or conserve all
possible organic matter in the soil. Where feasible, mulching of
dooryard citrus trees is desirable, but where a heavy mulch is
used the amount of nitrogen in the fertilizer may have to be
reduced. Some trees will be located on lawn areas as specimen
trees, and it is possible to grow lawn grass under trees, and
Saint Augustine grass is particularly suited to growing in
shaded areas. Where this is done it will be necessary to prune
off low limbs up to four or five feet above ground and keep the
tops of the trees thinned to allow some sunlight to penetrate the
canopy of foliage. Clearing small areas around the tree trunk
reduces competition for food and moisture. Do not allow the
root area to dry out, or to become waterlogged in periods of high
rainfall. Drainage ditches must be provided in some locations
to take off excess rains, and most locations will need some water-
ing during the usual spring and fall drought periods.

There is no formal method of pruning citrus trees. They
are usually allowed to form their own tops naturally and are
pruned only for specific reasons. Of these the most important

Dooryard Citrus Plantings in Florida

is the periodic removal of dead wood, including small twigs. This
should be done two or three times a year in dooryard trees that
are not sprayed. The fungus which causes melanose grows in
these dead twigs and the spores developed drop on young fruit and
leaves and cause melanose lesions. All cuts should be made clean
and close to the main limb. Stubs may die and constitute a
point of infection for wood decay fungi. It is hardly necessary
to use wound dressing on cuts less than one inch in diameter.
In the case of larger dead limbs, smooth and clean cuts should
be made back to a live limb and covered with pruning paint.
Water sprouts appearing in the center of the tree should be
rubbed off because they furnish a good place for starting scale
and whitefly infestations. If large holes develop in the canopy
of the tree due to the breaking of limbs by storms or other rea-
sons, it is sometime desirable to allow a watersprout to develop
into a branch large enough to fill out the canopy.
Where improper cuts have been made on large limbs and
decay has started in the cut area a certain amount of surgery
may be necessary to stop the spread of wood decay. Decayed
wood can be removed with a sharp chisel down to the live wood
and the cavity carefully smoothed up and painted with wound
dressing and kept painted until the cut area heals. Pruning
paint made of neutral asphalt without any penetrating solvent is
recommended for wound dressing. It waterproofs the cut until
it will callous over and will not harm the cambium. When re-
moving rotten wood, leave all cavities so that they will drain
Pest Control

The average dooryard planting is not located conveniently
for spraying with commercial equipment and even when it might
be convenient, it would be quite costly to purchase the necessary
equipment. Where the appearance of the fruit is not important,
spraying may be entirely omitted. In this case a considerable
percentage of the fruit may be marked by rust mites. This does
not injure the inside of the fruit, but may reduce the size some-
what. If the fruit is held late in the season it may dry out under
the brown marking because of increased evaporation at that

Florida Cooperative Extension Service

Rust mites can be controlled by dusting the trees with sulfur
dust after blooming and at about six-week intervals until harvest.
If only sulfur dusting is done it may not entail any other spray
operations. But if copper or zinc is used, as in commercial
groves, oil spraying will be a necessary operation to reduce scale
For average citrus plantings that are sprayed, the first ap-
plication is usually a zinc sulfate and sulfur spray before growth
starts in the spring, a post-bloom spray of copper and sulfur, an
oil spray in June or July, and one or more applications of sulfur
in late summer or fall. Such a program would be too much of a
burden on the owners of most dooryard plantings. Where bright
fruit is desired and the planting is accessible, commercial spray
equipment would be advisable to carry out such a program rather
than attempting to do it with small, low-pressure equipment.
Scale insects constitute the most serious insect problem and
if they become numerous will have to be controlled. A good oil
emulsion at a concentration of about 11/3 percent actual oil, or
5 tablespoonfuls of 80 to 84% oil in 1 gallon of water, in the
spray mixture usually will control scale with one spraying per
year. Commercial emulsions can be obtained from seed and fer-
tilizer dealers and used according to directions on the container.
It should be remembered, when spraying with oil to control
scales, that only those scales are killed which are thoroughly wet
with the spray, and the application must be made so as to cover
both sides of the leaves as well as the twigs and branches.
When no spraying is practiced, the scale problem usually
settles down to a satisfactory biological balance between the
scales and their natural enemies, but occasionally they may be-
come serious.
For more complete information on pest control refer to the
"Better Fruit Program" published each year by the Florida
Citrus Commission at Lakeland, Florida.

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