Novel Jatrophas for Florida Landscapes
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6-7) most elements are available to plant roots but as pH Soluble forms of minor elements are used as foliar sprays increases phosphorus becomes fixed in calcium compounds to give rapid, though temporary, correction of problems. A and iron and manganese may precipitate or be changed to a better approach is preventing deficiencies with a regular form in which plant roots cannot use them. Although readily program of soil applications and foliar feeding that includes available above pH 7 magnesium deficiency is very wide minor elements. spread because the heavy rains of south Florida leach this The list that follows (Table 1) includes species native to element (2). south Florida soils (3) and exotic plants that tolerate high Iron and manganese deficiency symptoms are similar in pH and the associated micronutrient levels. All will benefit most plants. Young leaves are affected first and show a from a regular fertilization program but were chosen be chlorosis that begins between the veins and may spread to cause they do not need heavy supplements of minor ele include the whole leaf. New growth may be smaller than ments or other special care and are reliable plants for the normal and in very severe cases may be stunted and dis landscape. A number of commonly grown species are ex torted, show dead areas, or may die completely. Palms are cluded because their nutritional needs to stay in perfect very susceptible to manganese deficiency: young leaves show health go beyond standard fertilizers with nitrogen, phos chlorosis together with stunting and distortion giving rise phorus and potassium. Many gardeners will be willing to to the name "frizzle top" (5). take on the additional micronutrient feeding needed in Magnesium deficiency also causes a chlorosis that begins order to enjoy them in their gardens. Local botanical gar at the leaf margins and extends between the veins, but in dens, such as Fairchild Tropical Garden or Flamingo Gar the case of this element old leaves are affected first. Some die- dens, are good places in which to see the wide range of back of leaf margins may occur but more often the leaves plants that will thrive with extra care and attention. The drop before there is much sign of necrosis. names used in the lists are from the "Checklist of Woody Gardening in areas of high pH can be a continuing Ornamental Plants in Florida." (1). battle against plant deficiencies. Soil treatment around af fected plants may be aimed at changing the pH to a more Literature Cited acid level or at supplying more of the deficient nutrient. Powdered sulfur has been effective in lowering pH in some 1. Burch, D., D. W. Hall and D. B. Ward. 1983. Checklist of Woody Ornamental Plants in Florida. Univ. Florida, Inst. Food Agr. Sci. cases, at rates of up to 1 lb. per 100 ft2, but a better long (in press). term approach is to mulch with organic materials that are 2. Dickey, R. D. 1977. Nutritional deficiencies of woody ornamental gradually incorporated into the soil in the natural course of plants used in Florida landscapes. Univ. Florida, Inst. Food Agri. composting. Sci. Bui. 791. 3. Gann, J. 1979. Selected list of south Florida native plants. Bui. Iron sulfate may be used as a soil amendment but is Fairchild Tropical Garden 34(2):20-22. quickly made unavailable and better results are obtained 4. Janick, J. 1972. Horticultural Science, 2nd ed. W. H. Freeman & Co. from chela ted forms of iron such as Versinol® or Seques- San Francisco. 586 pp. trene®. Sequestrene® 300 works well on the sandy soils but 5. Marlatt, R. B. 1980. Noncontagious diseases of tropical foliage plants. Univ. Florida, Inst. Food Agr. Sci. Bui. 812. the more expensive Sequestrene® 138 may be needed on 6. Smith, F. B., R. G. Leighty, R. E. Caldwell, V. W. Carlisle, L. G. marl. Chelates or fritted forms of manganese are also avail Thompson Jr., and T. G. Mathews. 1967. Principal soil areas of able for soil application. Magnesium may be applied to the Florida. Univ. Florida, Inst. Food Agr. Sci. Bui. 717. soil as Epsom salts (magnesium sulfate) or as dolomitic limestone even though this is adding more calcium (2). Proc. Fla. State Hort. Soc. 95:277-280. 1982. NOVEL JATROPHAS FOR FLORIDA LANDSCAPES Bijan Dehgan tionally deprived sandy soils of Florida. Examples of lesser University of Florida, IFAS, known species and artificial hybrids are discussed. Department of Ornamental Horticulture, Gainesville, FL 32611 Jatropha L. is a large genus of diverse growth forms and attractive monoecious or dioecious plants. The 150-175 spe Abstract. Jatropha L. is a morphologically diverse genus cies are woody trees, shrubs and subshrubs of disjunct dis of widespread geographical distribution in the seasonally dry tribution in the seasonally dry tropics of the Old and the tropics. The 150-175 species of the genus are found in Africa, New World. Two distinct groups were recently recognized India, and South and Central America extending through (6); subgenus Jatropha includes the African, Indian, South Mexico to southern Arizona and Texas. Two species used in American, Antillian and two of the relict north American south Florida landscapes; J. integerrima Jacq. ( = J. hastata taxa, while species of subgenus Curcas (Adans.) Pax are Jacq.) and J. multifida L. are indigenous to Cuba and prob predominantly Mexican, a few extending into Texas and ably Barbados, respectively. A third species seen occasionally Arizona. Of these, /. integerrima Jacq. ( = /. hastata Jacq.) (J. podagrica Hook.) is probably native to south Central has been cultivated in Florida for many years. Two other America. Although the majority of the species are potentially species; /. multifida L. (the coral plant) and /. gossypiifolia most useful for south Florida, there are some that can be (the bellyache bush) are not only in cultivation as orna grown in north and central regions of the State. Jatrophas mentals but are reported (14) to have naturalized in parts are low maintenance plants that should do well in nutri- of Florida Keys. These 3 species, in addition to /. podagrica Hook., which is seen in cultivation occasionally, are mem Florida Agricultural Experiment Stations Journal Series No. 4238. bers of subgenus Jatropha. Jatropha curcas L. (the physic Proc. Fla. State Hort. Soc. 95: 1982. 277 nut), is also cultivated in Florida (10). This species, a tree as "iVIata Muchachos" in Chihuahua or "jiotillo" in Sinloa, with nocturnally fragrant yellowish green flowers, has been it has been used for medicinal purposes. placed in subgenus Curcas. Jatropha curcas L., much cultivated in the tropics. Its In a genus of such diversity as Jatropha, there remains a exact origin is unknown, though possibly Mexico (8, 15). A fair percentage of choice species awaiting horticultural dis small tree with stout branches and roundish, angular to covery. Unfortunately, many nurserymen and plant lovers shallowly 3-5 lobed, 10-15 cm wide glabrous leaves. Green have shied away from cultivation of this genus because ish-yellow flowers are borne in contracted, many-flowered Cnidoscolus species with painful stinging hairs were classi corymbose cymes. This plant is frequently used as a hedge fied (11) as Jatropha. Hortus Third (1), the most widely in the tropics because the cuttings root quickly and the used manual for cultivated plants still recognizes Cnidos plant is not eaten by livestock. Commonly known as "physic colus as a part of Jatropha, despite the fact that these taxa nut" due to its medicinal properties particularly as a purga are but distantly related (6, 7, 9). In addition to stinging tive. Although reported to be poisonous, the seeds are quite hairs, Cnidoscolus differs from Jatropha by its white, palatable when roasted. (An interesting account of uses of apetalous flowers and milky latex, which imply a closer this species can be found in Standley, 13). affinity with Manihot than Jatropha. Jatropha hieronymii O. Ktze. from Argentina. This spe Jatrophas are potentially useful but underexploited cies has thick branches and lobed, somewhat gray colored, specimen plants for subtropical and tropical landscapes, dentate leaves and large yellow flowers on compact short whose diversity allows adaptation to many landscape situa cymes. The unusual color of the flowers give a unique char tions. Unintroduced artificial interspecific hybrids have acteristic to this plant. Probably useful as a specimen or con broadened the range of possibilities by providing inter tainer plant. Closely related to /. podagrica and /. augustii. mediate colors, forms and textures. Nearly all jatrophas seem Jatropha mcvaughii Dehgan & Webster,, from Mexico. capable of withstanding the poorest of growing conditions, Originally described as /. curcas var. rufus McVaugh how although a few of the xeric or succulent species may suffer ever, considered distinct (5) because of its much larger and from excess moisture in poorly drained soils. Once estab densely pubescent foliage and dioecious habit. This is a lished in the Florida landscape, the species and hybrids more attractive plant than /. curcas for landscaping and will herein described should require little supplementary irriga not become weedy if only male or female plants are used. tion and fertilization. Nearly all can be easily propagated Jatropha multifida L. Origin uncertain but probably in from cuttings or by seed which may be obtained by selfing digenous to Barbados; with stout branches and nearly of the monoecious species (except /. moranii Dehgan 8c orbicular, deeply 7-11 lobed (divided) leaves and thread Webster which does not self) or crossing of the dioecious like stipules. Flowers are brilliant scarlet, on long stalked taxa. Caudex-forming species, however, will not produce inflorescences. A very attractive and widely cultivated spe their unique, swollen stems when vegetatively propagated, cies throughout the tropics and is commonly known as coral and must be grown from seed if the caudex is a desirable plant or French physic nut.