Title: Rose growing in Florida
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Permanent Link: http://ufdc.ufl.edu/UF00026350/00001
 Material Information
Title: Rose growing in Florida
Alternate Title: Bulletin 78 ; Florida Agricultural Extension Service
Physical Description: Book
Language: English
Creator: Floyd, W. L.
Watkins, John V.
Publisher: Agricultural Extension Service, University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: October, 1934
Copyright Date: 1934
 Record Information
Bibliographic ID: UF00026350
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: aab7732 - LTQF
amt7048 - LTUF
35582073 - OCLC
002570735 - AlephBibNum


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The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source

site maintained by the Florida
Cooperative Extension Service.

Copyright 2005, Board of Trustees, University
of Florida

(A Revision of Bulletin 59)

(Acts of May 8 and June 30, 1914)


Fig. 1.-The rose-beautiful, fragrant, subtle flower of sentiment, romance
and history.
Bulletins will be sent free to Florida residents upon application to

Bulletin 78

October, 1934


GEO. H. BALDWIN, Chairman, Jacksonville
A. H. WAGG, West Palm Beach
J. T. DIAMOND, Secretary, Tallahassee


JOHN J. TIGERT, M.A., LL.D., President of the University
WILMON NEWELL, D.Sc., Director
A. P. SPENCER, M.S., Vice-Director and County Agent Leader
R. M. FULGHUM, B.S.A., Assistant Editor
JEFFERSON THOMAS, Assistant Editor
E. F. STANTON, Supervisor, Egg-Laying Contest
RUBY NEWHALL, Administrative Assistant

W. T. NETTLES, B.S., District Agent
H. G. CLAYTON, M.S.A., District Agent, Organization and Outlook Specialist
J. LEE SMITH, District Agent and Agronomist
W. E. EVANS, B.S., Assistant District Agent
R. W. BLACKLOCK, A.B., Boys' Club Agent:
HAMLIN L. BROWN, B.S., Dairyman
E. F. DEBUSK, B.S., Citriculthrist'
N. R. MEHRHOF, M. AGR., Poultryman
WALTER J. SHEELY, B.S., Agent in Animal. Husbandry'
C. V. NOBLE, Ph.D., Agricultural Economist2;
FRANK W. BRUMLEY, M.S.A., Agricultiral. Economist,' Farm Management
R. H. HOWARD, M.S.A., Asst. Aipr. Eco iomi t, Farm Management.
D. E. TIMMONS, M.S.A., Agricultural Econamist, Marketing
CARLYLE CARR, B.S., Specialist in Rodent Control1

LUCY BELLE SETTLE, B.S., District Agent
RUBY McDAVID, District Agent
ANNA MAE SIKES, B.S., District Agent
VIRGINIA P. MOORE, Home Improvement Agent
ISABELLE S. THURSBY, Economist in Food Conservation
EVA R. CULLEY, B.S., Acting Nutritionist

A. A. TURNER, Local District Agent

1In cooperation with U.S.D.A.


We like roses partly because of the effect on the senses of
their form, color, or fragrance, and because there is something
more subtle which draws us to the flowers of this plant, when
there are so many others that are beautiful in form, striking
in color and delightfully fragrant.
Probably the long history and popularity of the rose in all
countries has something to do with our fondness for it. As an
emblem of youth it was, in the long ago, dedicated to Aurora.
By others, as the emblem of youth and beauty, it was dedicated
to Venus. It is the symbolic flower of our mother country,
England, where it has held a conspicuous part in legend, song
and history for many centuries.
A rose suspended from the ceiling enjoined secrecy regarding
what was said and done at ancient banquets, hence the expres-
sion still current, "sub rosa."
No other flower has had so much sentiment, romance and
historic association connected with it.
Native roses are found growing in all temperate countries of
the northern hemisphere. These have made possible the develop-
ment of varieties adapted to different regions and multiplied the
number so that there is large opportunity for selecting favorites
and giving some reasons for their selection.

Roses are classified, according to origin or the species from
which they came, into a number of garden groups. These have
been so much mixed that their original characteristics overlap
at many points.
Teas:-These are especially adapted to the Gulf Coast region
and California, being easily injured by co!d. Some of our most
robust growers are found among them, though they are con-
sidered as weaker than hybrid teas in regions just to the North.

Professor of Horticulture and Assistant Horticulturist, respectively,
University of Florida College of Agriculture. The authors express their
appreciation to Mr. Erdman West and Prof. J. R. Watson of the Experiment
Station for valuable suggestions concerning diseases and insects.

Florida Cooperative Extension

The flowers have a wide range in color and are characterized by
a tea-like fragrance and continuous blooming, except during the
coldest winter months.
Hybrid Teas:-These are more nearly perpetual bloomers than
the group so named; the bushes are vigorous but rather small,
so are best planted closely together in beds. They comprise
practically all colors possible in a rose, many with pointed buds
and strongly tea-scented flowers. More hybrid teas than any
other type are planted in Florida.

Fig. 2.-Betty is a coppery pink hybrid tea that is attractive.

Hybrid Perpetuals:-This group includes the largest roses,
borne on stiff, upright stems, with rough, deep green foliage.
They produce flowers on shoots developed from previous year's
wood, while those of teas and hybrid teas are on current season's
growth. The flowers are inclined to be flat, and are very full,

Rose Growing in Florida

but lack fragrance. In Florida they usually produce two crops
of flowers, one in spring and another in autumn.
Polyanthas:-These are of dwarf habit, nearly ever-blooming,
with shapely bushes and flowers in clusters. They come in
various shades of color but lack fragrance. Cecile Brunner and
the Baby Rambler are representative varieties.
Noisettes, Hybrid Wichurianas, and Cherokees are other groups
of some importance.

Fig. 3.-Francis Scott Key, large, deep red, thrifty-one of our favorite dozen.

Florida Cooperative Extension


Listed below are the favorite dozen roses of the authors. The
first five are teas, the best group for Florida:
Madam Lambard: Darker on outside of petals than on the
inside, stems rather short. The most vigorous pink we have.

Fig. 4.-The Radiance is the easiest grown and most reliable pink hybrid tea.
One of our favorite dozen.

Safrano: Salmon colored buds of exquisite shape, semi-double
Maman Cochet: Rosy pink, double flower of fine form and
substance. The White Maman Cochet is also good as a bush
and there are climbing varieties of both.

Rose Growing in Florida

Marie Van Houtte: Light yellow, edged with rose; very strong
Lady Hillingdon: Slender, pointed buds and flowers of saffron
yellow. The climber of this is more vigorous than the bush form.
Antoine Rivoire: Creamy-white delicately tinted with pink.
Hybrid tea.

Fig. 5.-Etoile de Hollande, a hybrid
tea with velvety crimson buds, is
anroher of r.ur fav.,ritt .1.:.I en.

Florida Cooperative Extension

Radiance: The most easily grown and reliable pink hybrid
tea. The Red Radiance is equally desirable.
Etoile de Hollande: A hybrid tea with velvety crimson buds
and flowers borne on strong, stiff stems.
Kaiserin Auguste Viktoria: A standard old hybrid tea. Flow-
ers are snowy white, with a tint of lemon in the center. The
climber of this is also desirable.
Francis Scott Key: Large, deep red, lasts well when cut,
thrifty growing hybrid tea.
Frau Karl Druschki: Often called White American Beauty.
A hybrid perpetual, with large, full, snow white blooms.

Fig. 6.-Paul's Scar-
let Climber blooms
profusely in the


Rose Growing in Floride

Louis Philippe: A Bengal rose, often called Florida rose. A
wealth of dark red blooms are produced continually. It is one
of the few that grow satisfactorily from cuttings.
In this selection we have not given long stems, so much desired
in cutting roses, much consideration; rather beauty in the gar-
den and in vases and baskets in the house. All important colors
are represented.
Desirable Climbers
Silver Moon: Vigorous, of rich foliage, bloom clear white,
single, with a mass of yellow stamens.
Yellow Banksia: Covered in spring with small fragrant
Devoniensis: Strong climber, bloom white tinged with pink.
Reine Marie Henriette: Tea, fine growing plant, producing
large cherry-red flowers.
Reve d'Or: A vigorous climbing Noisette; flowers creamy
Paul's Scarlet: Hybrid Wichuraiana, vivid scarlet shaded
crimson, blooms profusely in spring.
Dr. Van Fleet: Hybrid Wichuraiana, rank climber, flowers
fresh-pink, deepening to rose in center.
Preference has been given to those which are vigorous, long-
lived, ever-blooming and resistant to diseases. Authorities on
rose culture in Florida have been consulted and the performance
of varieties growing in our college gardens has been closely
The following are some other varieties which we have found
to do fairly well in Gainesville.
Alexander Hill Gray-yellow, not very prolific, difficult to find
perfect flowers.
Duchess de Brabant-pale pink.
Helen Goode-creamy white.
Minnie Francis-dark pink.
Natalie Bottoner-cream yellow.
Perle des Jardins-cream yellow.
Hybrid Teas
Betty-coppery pink.
Dean Hole-splashed silver carmine.

Florida Cooperative Extension

Duchess of Wellington-saffron.
Etoile de France-red.
Jonkeer J. L. Mock-pink.
Joseph Hill-yellow, pink edges.


Fig. 7.-Joseph Hill, a yellow hybrid tea with pink edges, makes an
attractive rose.

.,- *

~ -t;


r~- *

Rose Growing in Florida

Gruss an Teplitz-crimson.
Mrs. Aaron Ward-Indian yellow.
Rose Marie-rose pink.
Mary Countess of Ilchester.
Hybrid Perpetuals
Anna de Diesbach-pink.
Paul Neyron-rose pink.
Pink Frau Karl Druschki-pink.
Crimson Frau Karl Druschki--crimson.

Baby Doll-shades of pink, saffron and crimson blended.
Baby Rambler-red.
Cecile Brunner-shell pink.
Edith Cavell-ox-blood red.

Fig. 8.-The Edith Cav-
ell is a desirable ox-
blood red Polyantha.

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Marechal Niel-yellow climber.
Lamarque-yellow climber.
Chromatella-lemon yellow climber.
Estelle Pradel-white climber.

Hybrid Wichuraiana
Silver Moon-white climber.
American Pillar-pink climber.
Dorothy Perkins-pink climber.

Fig. 9.-The Silver Moon, a hybrid Wichuraiana, is a desirable white climber.
The one shown here was used in a hedge.

Anemone-pink climber.
Fortune's Yellow-blend of yellow, orange and pink, climber.
White Cherokee-white climber.
Ramona-red climber.

Rose Growing in Florida

Fig. 10.-Antoine Rivoire, a hybrid tea with creamy white blooms delicately
tinted with pink, is another of our favorite dozen.

Florida Cooperative Extension

Roses are easily grown from cuttings, and a few varieties,
such as Louis Philippe, Banksia, Cherokee and McCartney do
well when so grown. Other vigorous kinds succeed when propa-
gated by cuttings if they are grown on clay-loam or low hammock
soils, but the weaker growers are satisfactory only when grafted
or budded on a vigorous, hardy stock, and this is especially true
if they are to be planted in a light sandy soil. Generally speak-
ing, in peninsular Florida improved varieties are unsatisfactory
on their own roots.
Many stocks have been tried and compared, among them
Madame Plantier, Rosa multiflora, R. canina, R. fortuneana,
and R. odorata. Rosa odorata (Texas Wax) is ordinarily a
long-lived plant, even under the trying conditions of peninsular
Florida, and can be relied upon to furnish an excellent under
stock for the popular cutting varieties.
Very often these improved varieties are not adapted to out-
door culture and the rosarian will be disappointed to find that
many of the kinds receiving glowing descriptions in the nursery
catalogs will last only a year or two. Most of the sorts of yellow
and copper shades will die out after their first summer, but rose
lovers quite often find that it pays to buy new plants of these
kinds every year and force them heavily during the first spring.
Under good culture, these rarer varieties will produce enough
of their strikingly beautiful flowers the first spring to repay
the gardener for treating them as annuals.

One usually cannot locate the rose garden where the soil is
best, but is forced to establish it where there is a suitable area
that is more or less predetermined by the design of the grounds.
It should not be situated near trees or large shrubs, whose roots
will rob the soil of plant food and water, and whose foliage will
intercept the sun's rays. Trees far enough away to allow not
less than five hours of sunlight a day, preferably in the morning,
may be tolerated provided that plenty of plant food and water
are given to supply what the roses need after the trees have
taken their toll. A root restricter, made by burying galvanized
roofing vertically along the edge of the garden nearest the trees
or shrubs will be beneficial in keeping out the roots for a year
or two. The plates must overlap several inches. It is advisable
to dig down to the bottom of this metal at least every two years

Rose Growing in Florida

to ascertain whether or not any of the roots have gone under or
between the plates.
An abundant supply of water is necessary, so some provision
must be made for the proper irrigation of the rose garden. On
the other hand, roses cannot stand wet feet, so a well-drained
location should be chosen. If this is not possible, raised beds
should be used to assure the passage of standing water.
In laying out the rose garden narrow beds, preferably not
over five feet in width, are recommended so that weeding, prun-
ing, dusting and spraying, and the gathering of the flowers can
be accomplished from walks on both sides. Tender new growth
is easily broken off by gardeners if they are required to walk
between the plants when working. Nothing surpasses turf for
garden walks. The grass, if properly grown and sheared, makes
well nigh perfect enframement for beds of roses.
It is considered good practice to arrange the rose garden with
trellises for climbing roses as a boundary to protect the more
delicate bush varieties from the winds. Dwarf Polyantha va-
rieties may well be used as an edging next to the walks.
For climbing and pillar roses, three feet is a satisfactory
planting distance. Hybrid Perpetuals and strong growing Hybrid
Teas should be planted two to three feet apart, while the less
robust Teas and Hybrid Teas succeed well in checks of either
18 inches or two feet. Polyanthas may stand as close as 14
inches in the row. Close planting is desirable because the shade
cast on the ground by the foliage is of benefit in keeping down
the soil temperature.
If the soil is loose, poor sand, remove it to a depth of 15 to
18 inches and replace it with a compost of rotted leaves, cow
manure, and good hammock soil. The older this compost is,
the better. It is necessary to add large amounts of organic
matter if the soil is a light sand. In western Florida, if the
garden be on a clay or clay-loam soil, this preparation is not
necessary. The addition of cow manure to the soil about three
inches thick, and turning it deep, is sufficient preparation usually.

The best planting time is when the plants are completely
dormant; this is usually in late December to early February,
but may vary, of course, in either direction as much as several
weeks. It is a good plan to obtain the bushes as soon as possible
after they become dormant so that the root systems may be

Florida Cooperative Extension

well established by spring. Choose an overcast day for planting
if possible. The plants should be carefully pruned back to four
or five eyes, and all broken or bruised roots should be cut off
clean and smooth.

Fig. 11.-The Duchess of Wellington is a saffron hybrid tea that produces
attractive blooms.

The holes for the plants must be sufficiently large to accom-
modate the root systems without crowding. In the bottom of
each hole drop two handfuls of bone meal, and cover it lightly
with top soil. Dip the roots of each plant in a bucket of water
just before planting. This is helpful in making good contact
with the soil particles. Insert the new bush so that the root
system maintains its former shape and position, and so that
the bush will stand at the same level that it grew in the nursery
row. With plenty of water, work the soil about the roots, filling

Rose Growing in Florida

the hole to the ground level. Pack firmly by trampling with
the feet, and put a large saucer of earth about the plant to hold

Fig. 12.-Mrs. Aaron Ward, a hybrid tea with Indian yellow blooms.

Florida Cooperative Extension

The mulch system is preferable to cultivation, especially
where plants are set close together. Cultivation, unless shallow,
destroys many feeding roots and causes the organic matter in
the soil to burn more rapidly. Moreover, there is danger of
breaking the new tender growth unless the tools are handled
with extreme care. Rose flowers are borne on new wood, so it
is quite evident that breaking off the new shoots will materially
reduce the number of blossoms.
If the rose garden has been laid out in beds the weeding, fer-
tilizing, pruning, and the cutting of the flowers may be done
by hand from the walks on both sides of the beds.
Cow manure applied two inches thick over the entire rose bed
is probably the best mulch. This material supplies plant food,
beneficial bacteria, organic matter, and serves as a blanket to
protect the roots from the hot sun. Early each spring the old
mulch should be worked into the soil and a new mulch should
be applied. If cow manure is objectionable or cannot be ob-
tained, cottonseed meal or tankage, three-quarters to one pound,
may be scattered about each plant and raked in lightly; then
the soil should be mulched with some organic material.
Granulated peat moss is an excellent mulch material. It has
remarkable water-holding capacity, adds organic matter to the
soil, and protects the roots from the hot sun. In addition to
its other advantages, peat moss is quite free of weed seeds.
Oak leaves, straw and lawn clippings are also valuable mulch
materials, but are inferior to peat moss.
When flower buds appear one-half to three-fourths of a pound
of a garden fertilizer analyzing 4% ammonia, 6% phosphoric
acid and 5% potash, applied about the plant by raking the
mulching material aside, scattering the fertilizer over the
ground, then raking the mulch back so as to cover it, will increase
the size and quantity of blooms. This may be repeated in Sep-
tember or early October if plants are not in vigorous condition.
Side-dressings of ammonium sulphate at the rate of one pound
to 100 square feet may be applied every two weeks during the
growing season, if the plants show a lack of nitrogen.

Rose Growing in Florida

Fig. 13.-Frau Karl Druschki, often called White American Beauty,
is another of our favorite dozen.

Florida Cooperative Extension

In addition to cutting back at the time of planting, rose
bushes should be carefully pruned twice each season. Bush
varieties are best pruned when most dormant, usually in early
February. Again in September they should be pruned in prepa-
ration for the autumn flush. Sharp pruning shears that will
make a clean cut are best for this work. Rough, ragged cuts,
split or broken canes will result, if improper tools are used.
First remove, close to the cane from which they arise, all
dead, blind and weak shoots, then cut back the strong stems,
removing at least a third of the old wood. Prune sufficiently
to give the bushes a symmetrical shape. The cuts are made
about a quarter to a half inch above a bud that points away
from the center of the plant. Bordeaux or sulphur paste or
ordinary lead paint should be applied to all pruning wounds as
they are made to forestall the entry of canker fungi into the
tissue. This is particularly important in old-established gardens
where canker is present.
Climbers should be pruned less than bush forms, but all dead
and weak wood should be removed as soon as found. If heading
back of the canes is necessary, this should be done after the
heavy blooming of the spring.
The art of pruning is gained by experience, and no specific
rules can be laid down. Different groups and varieties require
different treatments, and the proper way to handle each is
learned through trial.

Early morning, while the dew is still on the leaves, is the
best time to cut roses. Select buds with two or more petals
open and cut them with as short stems as possible. Cutting
roses with long stems is sometimes necessary, but this practice
greatly reduces the leaf area, and thus causes a serious check
to the plant. A plant is dependent upon its leaves for its wel-
fare, and if it is to succeed, it must not be defoliated. Small,
sharp pruning shears are best for cutting roses. The cut should
be made on a slant, just above an eye which points away from
the center of the bush.
As soon as possible after the buds are gathered, place them
in a deep vessel of cold water and hold in a cool place for an
hour or two before arranging them. Flower arrangements should
not be placed in a draft, in direct sunlight or near heating ap-

Rose Growing in Florida

pliances. Each day cut a half inch or so off of the end of each
stem, and renew the water in the container.

Fig. 14.-Rose Marie,
hybrid tea with at-
tractive rose pink

The rainy season is attended by a flush of growth which
produces a profusion of roses. After the rainy season very often
a long drought condition is experienced. At this time the plants
may be allowed to rest in preparation for a season of blooms
in the early fall. During this rest period irrigation may be
withheld and the plants should be pruned in September so as

Florida Cooperative Extension

to make them shapely and compact. With the advent of cool
weather an abundant supply of water and plant food will bring
the rose bushes into a flush of growth which is necessary for
the production of bloom. Every rosarian knows that roses will
not bloom unless they grow, and that he must expend consider-
able effort to make conditions favorable for this growth.

Fig. 15.-Gruss an Teplitz, crimson-flowered hybrid tea.

Rose Growing in Florida

Those living near cities or large towns may find a market for
well-formed roses of good quality, on long, stiff stems. The
Radiances are the most satisfactory as a rule, though many
other varieties are being grown commercially.
A fertile, well-drained location is important. This should be
well manured and prepared before planting. Cow manure in
liberal quantities, or cottonseed meal or tankage, if manure is
not obtainable, broadcast and plowed or disked in at the rate
of one to three tons per acre at least two weeks before planting
is a good preliminary preparation.
It is best to set the plants in rows three feet apart, spacing
them one and a half or two feet in the rows.
Mulching is not practicable for large areas, so abundant fer-
tilizer and a limited amount of shallow cultivation should be
given. Cultivation should be resorted to only as often as neces-
sary to keep down weeds and grass.
When flowers begin to form, an application of 1,000 to 1,500
pounds of garden fertilizer, already described, may be made
and cultivated in lightly, to increase size and quality of the
bloom. During the rainy season apply one to two tons of raw
bone meal per acre and occasionally chop down all weeds with
a hoe. In the hot, dry period following the rainy season, prune
lightly, removing all weak wood and cutting back very long
stems. Plants usually take a partial rest at this time, which
prepares them for vigorous effort a little later.
About the middle or latter part of September fertilize and
cultivate as in the spring and irrigate if possible, if rains are
infrequent. This will stimulate growth on which November and
December blooms will form.
When cold checks the blooming, prune carefully and allow the
plants to rest until swelling buds indicate that growth activity
has begun, then begin fertilization, irrigation and cultivation
as done the year before.
Some growers, especially on the lower East Coast, are suc-
ceeding with roses on muck lands. As such soil is usually rich
in nitrogen, the proportion of this element is reduced in the
fertilizer, but phosphorus and potash are used liberally. No
satisfactory fertilizing plan can be given as the chemical and
physical condition of these soils is quite variable. Well-balanced
fertilization, careful attention to drainage, cultivation and other
factors important in upland growing will insure success.

Florida Cooperative Extension

Adequate moisture is indispensable in the production of roses,
and some provision must be made for an irrigation system.

Rose aphids, or plant lice, at times are serious pests in the rose
garden. They may gather in great numbers on the tender new
growth and about new buds. Stunted shoots and imperfect
blooms are the result if the insects are allowed to go unchecked.
Nicotine and soap sprays or nicotine dust are efficient controls.
Rose beetles occasionally feed on the tender buds. It is im-
portant'that thistles be destroyed because they are hosts to rose
Flower thrips are extremely troublesome during dry seasons.
They are tiny, light-yellow insects that infest the blooms in
numbers beyond estimation. Browned petals and balled buds
that fail to open (similar to the injury caused by rose canker)
often resu-t from the attacks of thrips. Some varieties of roses
are more seriously injured than others. Water seems to be the
most efficient control. All roses should be gathered as soon as
they open sufficiently, and frequent applications of nicotine
should be made if these insects are numerous. As weeds and
flowers of many kinds harbor thrips, a careful cleanup program
is recommended.
Pumpkin bugs often attack roses, especially during the fall,
and punctured buds of abnormal shapes result from their feed-
ing in the rose garden. Knocking them off into a pan containing
a little kerosene may be resorted to. Spraying is of little or no
value. Thistles harbor pumpkin bugs, so they should not be
allowed to grow near the rose garden. Catch crops, such as
sunflowers, may prove of benefit if the bugs are systematically
collected from them.
Cottony-cushion scale, when found feeding on the under sides
of leaves or on the canes, is best controlled by colonies of Vedalia,
a small beetle which is a specific predator. A citronella spray,
if applied under very high pressure, will give an effective check.
It is possible to reduce the infestation by washing the scale from
the bushes with a vigorous stream from the nozzle of the garden
Red spider may be kept in check by dusting with sulphur or
by heavy syringing with the hose.

Rose Growing in Florida

Black spot is one of the most serious diseases with which the
rosarian has to contend. It is first evident in the form of minute
irregular black spots on the upper surface of the leaves. As
the fungus grows, the leaves turn yellow and drop off. When
the leaves are severely infected during humid weather they
may shed without turning yellow. The infection starts near
the ground and spreads upward on the pant until it is nearly
defoliated. This reduction of the leaf area is a serious check,
and stunted bushes, bearing a few small blooms, are the result.
The leaves which fall off are a serious source of infection, since
they produce myriads of spores of the fungus, and thus it is
very important that all infected leaves be burned.
Black spot is especially prevalent during hot, humid weather,
and at this time special precautions should be taken to protect
the rose garden from the ravages of this disease. So far as
known there is no cure for black spot, so preventive measures
are the only means of control.
Copper compounds, such as bordeaux mixture or ammoniacal
copper carbonate, a colorless spray, are efficacious if frequent
applications are made. Spreaders, such as calcium caseinate,
soaps or oil emulsions must be used with these materials to
assure good coverage. The disease spreads so rapidly that a
coating of some fungicide must cover the plants at all times to
forestall the entrance of the fungus into the tissues of the plants.
Plants in vigorous growth seem to be less severely injured than
are the weaker individuals.
Recent research has shown that very fine sulfur is effective
in controlling black spot if a coating of the material is kept on
the leaves. Sulfur must be very fine for controlling fungi, and
the grade known as 300 mesh, used as a spray, or as a dust, is
effective. Dusting is usually preferable, all things considered.
Sulfur sprays may be bought in the form of paste. During the
summer, rose foliage that is covered with sulfur very often
suffers considerable injury from burning.
Powdery mildew is sometimes a serious menace to roses,
especially the climbing varieties. Dorothy Perkins and Crimson
Rambler and many of the common bush varieties are highly
resistant. The leaves and shoots of affected plants become
dwarfed and covered with a grayish-white coating. The shoots
and buds of highly susceptible varieties become deformed.

Florida Cooperative Extension

Sulfur fungicides, dusts or sprays, are satisfactory for the
control of mildew. Bushes sprayed with these for the control
of other diseases seldom suffer from mildew.
Rose canker causes the failure of more rose gardens than
any other one trouble. Several fungi causing similar symptoms
are responsible for the trouble. The canes are the part most
frequently attacked. Small purplish spots develop along the
stem, and as they enlarge they become grayish or brownish in
the center. As soon as a cane is girdled, the upper portion dies.
The fungus usually continues down the stem, unless pruned out.
If it reaches the crown, the whole plant dies. The disease fre-
quently begins around pruning cuts and other injuries, from
which it spreads rapidly, killing the bark as it progresses.
The leaves are less often affected and usually less severely.
The flowers are often attacked by the fungus. The outer petals
are killed and turn brown and dry. The flower is bound so
tightly by these dead petals that it fails to expand. This con-
dition is frequently confused with thrips injury.
Either a copper fungicide or one containing finely divided
sulfur may be used after the removal of all affected canes. The
fungicide must be applied consistently and thoroughly. All
parts of the plant must be kept covered with the protective
coating. During periods of rapid growth and damp weather,
it may be necessary to app!y a fungicide once a week or oftener,
but ordinarily once every 10 days or two weeks is sufficient. It
is necessary to add a sticker to the spray in all cases to obtain
maximum protection.
Pruning wounds should be covered with lead paint or bordeaux
paste immediately after they are made. Further protection may
bB obtained by dipping the shears in alcohol or formalin solution
after each cut.
When setting a new rose bed, be careful that only healthy
plants are used. It is easier to keep rose canker out of the garden
than to cure it after it is present.
The following press bulletins on these diseases may be ob-
tained free from the Florida Agricultural Experiment Station
at Gainesville: Press Bulletin 447, Rose Canker; 448, Black
Spot; and 449, Powdery Mildew.

Rose Growing in Florida

1. Locate the rose garden so that it receives at least five hours
of sun each day, and avoid trees and large shrubs.
2. Buy rose bushes that are budded or grafted on a suitable
3. Enrich the soil before planting.
4. Plant bush varieties in beds, 18 to 24 inches apart each way.
Give climbers more room.
5. Plant at the same level that the bushes stood in the nursery
6. Group a number of individuals of each variety together to
get the effect of color masses.
7. Use a heavy mulch of some organic material.
8. Give plenty of water and plant food. Fertilize two or three
times during the growing season. Remember that roses
must grow to bloom.
9. Prune twice each season. Remove dead, infected and weak
wood. Give heaviest pruning when plants are dormant.
10. Watch for black spot and rose canker, and dust or spray
with a good fungicide.
11. Replace weak, unthrifty plants, two or more years old.

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