SEMINOLE COUNTY URBAN HORTICULTURIST
One of the best climbers for central Florida is the yellow Allamanda. A native to Brazil and relative to oleander and confederate jasmine, this vine produces very showy yellow flowers nearly year-round. It is a very popular flowering vine for home gardens but must be protected from frost. There are three main species cultivated, the common yellow Allamanda, with the bright yellow flowers, the bush Allamanda with yellow flowers streaked with orange, and the purple Allamanda with its large magenta-violet flowers.
The plant: The yellow Allamanda is a woody evergreen vine, with a milky sap, often pruned to grow as a shrub can grow up to 15 feet tall. The leaves are leathery and glossy, lance-shaped or elliptical, opposite or sometimes in whorls of 3 or 4, measuring up to 6 inches long. The flowers, clustered near the ends of the branches, are yellow, very showy, waxy, trumpet shaped, with 5 flaring petal lobes, measuring 2 to 4 inches across. The main flowering season is summer and fall, but produces flowers throughout the year. The fruit is a prickly capsule measuring about 2" wide. When mature, it splits open releasing winged seeds. The fruit is rarely seen in Florida.
Culture: Allamanda requires full sun to light shade. It must be planted in a protected area because its tenderness to frost. It freezes about 30°F. It tolerates many soil types with good drainage, can grow well in acid to alkaline pH but grow best with pH values between 5.5 to 6.0. It has a relatively high drought tolerance once established. Prune severely before growth starts in spring, and keep shoots trimmed during the year because it grows very quickly and can cover the fence, trellis or tree where it is growing very rapidly. Prune to develop a low, upright, spreading shrub that will produce more blooms. It requires very little care. Fertilize lightly in the spring and in fall with a general complete fertilizer. It may show iron or manganese chlorosis in alkaline soils.
Varieties: The "Henderson" and "Brown Bud" are two of the most popular cultivated varieties. The variety "Golden Butterflies" has yellow tubular flowers with petals that flap in the wind like butterfly wings; "Halley's Comet" has both double and semi-double yellow flowers; "Caribbean Sunrise" has pink flowers; "Hendersonii" has smaller yellow flowers than other cultivars, unopened buds are brown on the outside; "Nobilis" has large open yellow flowers, buds are brown outside and the flower tubes are narrower in diameter than other varieties; "Jamaican Sunset" has smoky pink flowers; "Schottii" has large yellow flowers which have swollen tubes and brown stripes inside.
Uses: This plant can be used in containers or planters, grows very well in a hanging basket and can also used as a ground cover. It can be used as a vine to cover fences or trellises, as a hedge or as a freestanding, clipped specimen. It can become a handsome houseplant.
Indoor use: As an indoor plant, Allamanda do best in at least 4 hours of direct sunlight a day, night temperatures of 60-65 °F and day temperatures of 70 °F or higher. Keep the soil moist and fertilize every two weeks from April through September. Apply less water and no fertilizer the rest of the year.
Propagation: Allamanda is usually propagated from stem cuttings obtained during the spring.
Toxicity: The plant is considered to be poisonous, but not know to be fatal. All parts of the plant, especially the fruit and seeds, and the sap of the stems and leaves, cause mild to severe stomach upset and vomiting. Bark is also said to be poisonous. It may cause dermatitis to sensitive persons. It is considered to have emetic and purgative properties. Toxin is self-limiting and treatment is usually not necessary.
Pest and diseases: Allamanda can be affected by plant parasitic nematodes. Mites and scales can produce some damage and should be controlled as soon as they are detected using insecticidal oil and soap sprays. Caterpillars can occasionally defoliate the plants severely.
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