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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
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Copyright 2005, Board of Trustees, University
Sf 1SG8 ,a AGRICULTURAL EXTENSION SERVICE
INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES
UNIVERSITY OF FLORIDA, GAINESVILLE
Circular 128B May 1967
AN1 71 oduction
in Fl rida
S.- Univ. of Fpr I EEHAN
ssocia e ornamental Horticulturist
Florida Agricultural Experiment
Although caladiums have been grown in Florida for many
years, it was not until 1940 that the industry began to expand.
It is estimated that there are now almost 700 acres devoted to
caladium tuber production. Highlands County is the center of
the industry, with between 400 and 500 acres devoted to com-
mercial production. Sebring is generally recognized as the
caladium capital of the United States and possibly of the world.
The annual production in the area is between 30 and 35 million
tubers, with another 10 to 15 million produced elsewhere in the
As early as 1910 Dr. Henry Nehrling in Orlando was noted
for his collection of fancy leafed caladiums. It has been stated
that he had 2,000 named varieties and shipped 100,000 to
150,000 tubers each year. Many of these varieties were Dr.
Nehrling's own hybrids, from crosses he made as early as
Caladiums are members of the Araceae family and are Tropi-
cal American in origin, with a large portion of them coming
from the Amazon basin in Brazil. Caladium bicolor is the
usual species in cultivation and is the species which has given
rise to many of the named forms cultivated today. C. pictura-
tur, native to Brazil and Peru, is also cultivated to some extent.
These two species are the parents of most of our named hybrids
in the trade.
Most of the tubers produced are used for forcing under glass
in the early spring months. They make ideal pot plant subjects
for Easter, Mother's Day and spring and summer sales. A small
percentage are packaged for home use and sold in retail and
1. Fancy Leafed Caladiums, Robert Mitchell, Ohio Florists Bulletin No. 228, Sept., 1948.
The number of varieties grown varies with different growers.
The larger producers will have up to 50 varieties under culti-
vation at one time, whereas some small growers will cultivate
only 2 or 3 varieties.
The majority of the tubers produced in Florida are grown in
open fields in moist muck pockets. These areas are acid, hav-
ing a pH near 4.5, which seems to be ideally suited for caladium
growth. Some are being grown
on sandy soils and as long as
these are irrigated and given
Sufficient fertilizer they will
produce good tubers.
J Propagation. Caladiums
/ can be grown from seed, but
\ when a new variety is selected
it is propagated vegetatively.
The plants produce tubers dur-
Fig. 1.-Caladium tuber. ing the growing season and
these become the propagating
stock for the following year. The tuber will have several eyes
or buds on the top and sides. It can be cut into as many pieces
as there are eyes (Figs. 1 and 2) and each piece will produce a
new plant. The general prac-
tice, however, is to leave at
least 2 eyes on each piece.
Planting.-There is consid-
erable variation among grow-
ers when it comes to planting
and spacing the chips (i.e. a
small piece of a tuber, con-
taining the eyes, that is used Fig. 2.-Caladium tuber sectioned
into "chips" for planting.
for planting stock). The av-
erage producer prepares his fields in late February and begins
planting in March and continues until all the chips have been
set. Some growers will still be planting in June. The main
reason for this long planting season is the soft nature of the
caladium tuber. The soft tuber has not lent itself to mechanical
digging and planting equipment. Hence, all this type of work
must be done by hand. The rows are spaced 18 to 24 inches
apart and the chips are planted from 4 to 6 inches apart in the
rows, and 3 to 4 inches deep. The spacing, between the rows will
depend entirely upon the type of equipment used in cultivating
the fields. Some growers plant up to 80,000 chips per acre.
Care in the Field.-When the field is prepared in the spring,
fertilizer is applied at the rates of 500 to 800 pounds of 8-8-8
per acre. This initial application is followed after planting by
2 or 3 sidedressings of 500 pounds of 4-8-8 or 3-10-12 per acre,
applied during the growing season. In general, most growers
will decrease the amount of nitrogen applied and increase the
amount of potash so that their last application will be 3-10-12
or a similar formula. The additional potash will mature and
harden the tuber and thus increase its storage potential.
Weeding is one of the biggest problems of the caladium indus-
try. Most growers are still hand weeding, while a few have
tried using various herbicidal treatments to control weeds. The
latter group is finding some materials very effective in keeping
the weeds under control. However, since all effective weed killers
have caused severe leaf burn, extreme care must be used in
applying the material. Shielding the nozzles has all but elimi-
nated leaf burn. One application of weed killer is effective for
6 to 7 weeks and eliminates 3 or more hand weeding or cultivat-
Roguing is a problem on fields that have been in caladium
production for several years. In digging, chips are left in the
soil and after mild winters they will produce plants the following
season. These rogues are pulled either during weeding opera-
tions or just before harvest time, when they are all removed in
Harvesting.-Caladiums stop growing with the first frost
and are usually harvested at that time. Growers begin digging
in November and continue until all the tubers are harvested.
Here, too, there is a great deal of variation in that some growers
prefer to harvest all the tubers at once, while others dig as they
fill orders. The latter group will still be digging in February,
when it is time to plant again. They will sometimes run into
heavier losses if there is an extremely cold winter, at which
time the tubers left in the ground may be injured by the cold.
Once the tubers are harvested they must be cured or dried.
Most are dried in open sheds or sheds with forced air drafts.
A few growers are using modified hay dryers, Although these
have cut the time of curing considerably, the cost of the equip-
ment has prevented most growers from adopting them. The
harvested tubers are placed in trays with slatted or wire bot-
toms, with the tubers 1 layer deep. The trays are then stacked
in the drying shed where they are air dried for 6 weeks or
mechanically dried for at least 48 hours. After the initial drying
period the tubers are stored 3 to 5 layers deep in trays to hold
for shipping or for storage for next year's plantings. The tem-
perature in drying and storage should not go below 60 F.
The tubers are graded before shipment. They have 4 classi-
fications, but only the 3 larger grades are customarily offered
for sale. The following are the grades used:
Mammoth--3%" or larger in diameter
Jumbo -2Y2-3 3%"
No. 1 -12-2%"
No. 2 -1 -1%"
The percentage of each grade produced varies from year to
year. Average production of caladium tubers runs 15% mam-
moth, 25% jumbo, 25% No. 1, 20% No. 2 and an average of
15% loss due to disease and other problems. These figures will
vary with variety. Some varieties will seldom produce a tuber
larger than a number 1, while others will produce a larger per-
centage of jumbos and mammoths. The largest part of the num-
ber 2 production goes into planting stock for the following year.
Some are sold in small packages for home owner use and a
few are used as forcing stock for small pot material.
Insects and Diseases.-Insects are generally not too trouble-
some in caladium production. Occasionally aphids and thrips
can become a problem. Large growers keep both of these under
control by spraying with parathion or malathion. Smaller grow-
ers and home owners can control both with malathion or can
use DDT spray or dust for thrips and nicotine sprays or dust
for aphid control. Cutworms have made minor attacks but have
never become a serious pest.
Nematodes are a problem in caladium culture. Soil steriliza-
tion of small plots has been very satisfactory in controlling
nematodes. The larger acreages do not lend themselves too
well to soil sterilization, although fumigation with materials
such as EDB can be used. When an infestation builds up, the
grower usually rotates his crop by planting on new land and
putting cover crops on his old land.
Southern blight (Sclerotium rolfsii) is a problem in some cala-
dium fields. This disease is soil-borne and can wipe out the
plants in very short order. Soil sterilization will help, but in
field culture it is difficult to control. All diseased plants should
be discarded and a good rotation program set up. As with nema-
todes, Southern blight is most prevalent on fields used for cala-
diums year after year.
Tuber rot also is common. It occurs when the tubers are
stored or held at temperatures below 500 F. for brief periods.
Chalking, or dry white rot of tubers, is another problem.
The cause of this malady is unknown. It occurs frequently in
storage, yet does not seem to be too deterimental to forcing
Foliar burns occur from time to time in the field and in the
greenhouse. These have been attributed chiefly to lack of water
or water damage to the root system, rather than to any disease.
Forcing Caladiums.-Tubers for forcing can be obtained from
mid-December on. Most tubers used in forcing are planted from
January to May. There is little known regarding the dormancy
requirements of the tubers, but it has been noted that tubers
planted in January do not grow as rapidly as those planted in May.
January forcing usually takes 6 to 8 weeks to produce a salable
plant, whereas those forced in May require only 4 to 6 weeks.
Growers forcing early will select varieties that have their color
marking on the juvenile leaves, leaving for late spring forcing
those varieties that show color only on the adult leaves. Actually
caladiums can be taken up at any time and dried for 2 to 3 weeks
and then forced again. An early crop that does not meet a
favorable market can be dried and forced for a later season.
Caladiums can be started in flats containing a mixture of 2
parts wet peat moss and 1 part sand, or they can be started
directly in the pots in which they will be sold. A minimum
temperature of 700 F. is required for forcing, with temperatures
between 800 and 900 F. being considered ideal. The tubers
should be placed in the flats so that they are barely covered with
the rooting medium. After the roots are 2 to 3 inches long the
tuber can be removed from the flat and planted in the pot in
which it is to be sold. The pot should contain a soil composed of
1/2 sandy' soil and 1/2 organic matter. One teaspoon of complete
fertilizer (6-6-6) per 5-inch pot will promote good growth. Once
growth begins the plants require large quantities of water, and
should be kept uniformly moist. Potted tubers are grown at a
minimum night temperature of 650 F. Although the tubers are
produced in the field under full sun, most growers force them in
partial shade with a maximum light intensity of 5,000 foot can-
dles. This lowered light intensity will frequently produce a
different color pattern on the foliage from that obtained under
When forcing tubers the
central eye will break first, ..
producing a few leaves in a k
large pot, with a few small
shoots developing later. The
best way to avoid this is to
section the tuber before pot-l
ting. If the tuber is cut into
3 or 4 pieces and these pieces
placed "back-to-back" they
will produce more shoots and Fig. 3.-Caladium tuber with central
will produce more shoots and eye removed for forcing.
leaves of uniform size. They
also will make a fuller pot for future sales. Others prefer to
cut out the central eye and thus force the lateral eye without
cutting the tuber (Figs. 3 and 4).
Varieties.-There are numerous varieties and named hybrids
on the market today. The demand for the different colors varies
considerably with locality and
season of the year. The nomen-
clature of varieties is very
confusing in that some varie-
ties are being sold under more
than 1 common name by dif-
ferent growers. The following
list of varieties and their brief
descriptions are those that are
Fig. 4.-Caladium tuber quartered the most popular today.
with green netted veins, border narrow and green. Most popu-
lar white and green variety. Popular Easter variety.
Lord Derby-pink or rose-red leaf, almost transparent, edges
and ribs deep green. (Hortulanus is similar.)
Ace of Hearts-deep rose center, borders of leaf green, ribs
scarlet and heavy.
Crimson Wave-crimson crinkled centers, large leaves deep
green, almost transparent, some crimson spots in the wide green
John Peed-metallic red center, with dark green border.
(Freda Hemple is similar.)
Porcile Anglais-metallic green edged, waxy leaves, centers
a deep crimson, a low-growing variety.
Red Ensign-metallic red, narrow green border, very bright
coloration, medium height.
Scarlet Pimpernelle-scarlet leaves, margin yellow or straw
colored, leaves large.
Spangled Banner-red glowing leaves, ribs darker red, numer-
ous pink spots. (John Hortmiester is similar.)
Thomas Tomlinson-bright crimson center, crimson blotches
in green border, produces large numbers of leaves.
Some additional named varieties in the trade include:
Mrs. Arno H. Nehrling
Mrs. F. Sander
Mrs. W. B. Haldeman
Tuoinphe de 1' Exposition
Dr. M. Cook
Dr. T. L. Meade (Blaze)
First Printing February 1955
Second Printing March 1960
Third Printing February 1965
COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June 30, 1914)
Agricultural Extension Service, University of Florida,
and United States Department of Agriculture, Cooperating
M. O. Watkins, Director
YOUR FUTURE IN
Professional training in scientific FLORI-
CULTURE can be obtained at the University
of Florida College of Agriculture. You can
prepare for a rewarding future as grower,
researcher, teacher, consultant, greenhouse
manager or other positions in a challenging
high income specialized field concerned with
the most scientific physiological and bio-
chemical aspects of plant growth.
There's a career
in agriculture for you
For further information, write
Dean M. A. Brooker, College of Agriculture
University of Florida, Gainesville, Florida