Looking at Plants
Allamanda cathartica
Allamanda cathartica
COMMON NAMES
Allamanda, Golden Trumpet
Allamanda (al-a-MAN-da) - named for Frederic Allamand, a Swiss botanist
cathartica (cath-AR-tee-ca) - cathartic
GROUP 
Dicot
FAMILY
Apocynaceae
ORIGIN
Brazil, South and Central America
DESCRIPTION
Allamanda is an evergreen shrub/vine that can be highly variable in size, but it is usually 4 to 5 feet when grown as a shrub and up to 20 feet if left to natural form as a vine. It is loose and spreading with a moderately fast growth rate.
Leaves are evergreen, oblong-shaped, simple, glossy, leathery, whorled in arrangement, 4 to 6 inches long, and light to medium green in color. It has pinnate veins, milky sap, and entire margins.
The yellow flowers are trumpet-shaped with a white throat marking, 5-petaled, and 3 to 4 inches across. It blooms throughout the year in warmer areas with a heavier flowering in the summer and from spring to fall elsewhere.
Fruit are prickly, spiked capsules.
HARDINESS
It is hardy in USDA zones 9 to 11. It starts to suffer damage at 30 degrees F.
LIGHT
Full sun for best flowering, but it will tolerate some partial shade with fewer flowers.
SALT
Slight to Moderate Salt Spray Tolerance – it will tolerate some spray, but it is best to have more protection such as a fence or building as an additional barrier behind the first row of plantings or the first dunes.
SOIL
It prefers a fertile soil in the pH range of 5.0 to 6.0, but it will grow on other well-drained soils. It may exhibit some chlorosis on alkaline soils.
WATERING
It has moderate drought tolerance once established, so some water is needed for survival in dry spells. As with most plants, though, ample irrigation in droughts keeps it healthier, looking better, and flowering more.
PROPAGATION
Hardwood or softwood cuttings taken in warm weather and put under mist
PRUNING
Pinch when young to promote bushiness. Prune as needed to control size or train as a vine, but preferably after heaviest flowering.
FERTILIZING
It has no special fertilizer needs. Unless a soil test calls for something different, a balanced analysis applied per the product’s label during the growing season will work. Reduce the nitrogen as winter approaches to keep the foliage from being too lush going into cold weather.
PESTS
Scale - University of California
Tetrio Sphinx, Giant Gray Sphinx, Frangipani Hornworm - University of Florida
Pink Hibiscus Mealybug - University of Florida
Citrus Whitefly - University of Florida
False Spider Mite, Brevipalpus californicus - University of Florida
DISEASES
Leaf Spots - Missouri Botanical Gardens
DEER
Resistant
There are very few totally “deer-proof” plants. There are also, relatively speaking, few plants that are considered a preferred food supply of deer. Most plants fall in the big gap between. One of the biggest variables is the available preferred food supply in a given area. If their preferred food is scarce, they will munch on most anything.
OTHER
USES
Flowering specimen plant, containers, trained as a small tree, background plant, trellises or arbors, cascading over walls and fences
Canadian Poisonous Plants Information System says: Golden-trumpet (Allamanda cathartica) is considered poisonous, but firm evidence is lacking. The plant was once used as a cathartic. Ingesting the fruits may cause upset stomach (Kingsbury 1964; Hardin and Arena 1969). Some individuals develop a rash from the plant sap (Morton 1962).
Merck Vet Manual says Allamanda cathartica as: Contains plumericin, a GI irritant found in the bark, leaves, fruit, seeds, and sap. Based on exposure dose (abdominal discomfort, diarrhea, dehydration, and electrolyte imbalance).
North Carolina State University lists Allamanda cathartica as: Poison Part:All parts - Poison Delivery Mode:Ingestion, dermatitis - Symptoms:Fever, swollen lips, thirst, nausea, diarrhea; skin irritation upon contact with cell sap - Toxic Principle:Unknown - Severity:TOXIC ONLY IF LARGE QUANTITIES EATEN; SKIN IRRITATION MINOR OR LASTING ONLY FOR A FEW MINUTES
Many other sources give the same basic information.
ADDITIONAL PROFILES
Allamanda cathartica 'Cherries Jubilee'
Allamanda cathartica 'Golden Butterfly'
Allamanda cathartica 'Hendersonii'
Allamanda cathartica 'Henderson Dwarf'
Allamanda cathartica 'Peaches and Cream'