Scandent, scrambling shrub to 6 m high. Leaves 4-whorled; blade elliptic to ellipticlanceolate, up to 17 cm long and 5 cm wide, glabrous; tip long-pointed; base cuneate to rounded. Flowers 80-110 mm long, 70-130 mm wide; corolla yellow to pinkish yellow. [A. grandiflora (Aubl.) Lam.; A. hendersonii Domb.; A. williamsii Gard.]

Brazil, Columbia, Cuba, Dominican Republic, Granada, Mexico, Peru, Surinam, Venezuela

A number of cultivars is known but these are mainly grown in tropical areas.

 

A. blanchetii A. DC., Purple Allamanda (Purple Trumpet Flower), from Brazil has purple trumpet flowers [A. violacea Gardner & Fielding].

A. schottii Pohl., Yellow Allamanda, also from Brazil has yellow to yellow-orange flowers only about 3 cm wide [A. neriifolia Hook.]; it is available as A. 'Grey Supreme' with leaves variegated grey and cream.

Source: Forster, P. (2002). Apocynaceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 4. Flowering plants. Dicotyledons. Part 3. The identification of garden and cultivated plants. University of New South Wales Press.