Allamanda cathartica
Common Name: golden trumpet 
Type: Broadleaf evergreen
Family: Apocynaceae
Native Range: Central and South America
Zone: 10 to 11
Height: 10.00 to 20.00 feet
Spread: 3.00 to 6.00 feet
Bloom Time: Seasonal bloomer
Bloom Description: Yellow with white throat markings
Sun: Full sun
Water: Medium
Maintenance: Medium
Suggested Use: Annual
Flower: Showy
Leaf: Evergreen

Culture

Tropical evergreen vine or shrub that is winter hardy to USDA Zones 10-11. Grow in organically rich, medium moisture, well-drained soils in full sun. Best flowering in full sun. Best performance occurs in hot and humid climates where nighttime temperatures do not dip below 60 degrees F. In St. Louis, this plant is grown as an annual or in containers or greenhouses. Container plants must be brought inside before first frost and overwintered as houseplants in large sunny rooms with intense bright light and moderate humidity or in a greenhouse. When grown as a vine, it must be trained to grow on a support structure because it does not twine or have tendrils/aerial roots. May also be pruned to grow as a shrub. Thin stems to promote air circulation if fungal diseases attack the foliage. Can be difficult to grow as a houseplant due to large size.

Noteworthy Characteristics

Native to Brazil, golden trumpet or common allamanda is a frost-tender, evergreen, tropical plant that is primarily grown as a climbing vine, but may also be pruned as a shrub. As a vine, it will grow rapidly to 20’. Features clusters of yellow, trumpet-shaped, single or double flowers with white throat markings and leathery, wavy-margined, obovate, light green leaves (4-6” long) that appear in whorls of 3-4 or in pairs along the stems. Blooms throughout the summer to first frost. As with most dogbane family members, the stems exude a toxic milky sap.

Genus name is in honor of Swiss botanist Frederik Allamand (b. about 1735, d. after 1776).

Specific epithet means purgative.

Problems

Watch for scale, mealy bugs and leaf spot. For more information see: Problems Common to Many Indoor Plants

Garden Uses

Grow as annual vine for porches, trellises, fences or through large shrubs. Container plant that can be overwintered indoors. In tropical areas, it is often grown as a hedge.