Allamanda cathartica: Golden Trumpet
It is only recently that this lovely plant began to be sold at the florist’s and at garden centres. The reason for its inclusion in the assortment offered by many nurseries is the growing number of centrally-heated homes as well as the changed emphasis on interior decoration and the demand for unusual flower ar-rangements.
The allamanda is a woody climber from Brazil, the home of 11 further species of the same genus, just one having ‘strayed’ to Central America. They are very good for covering a lattice-work room divider, for framing a window with greenery, as well as for large window glasshouses and indoor glass plant-cases. Whereas in the wild they grow to a height of about 6 m (20 ft) in cultivation they rarely reach a height of more than 2 m (6 ft). The leaves, which are firm and leathery, are arranged in whorls of 3 or 4. Theare broadly funnel-shaped, the individual petals opening wide at the mouth. Those of the species, which is the most widely grown, measure up to 12 cm (4-3/4 in) in diameter.
In cultivation, A. cathartica flowers from mid-summer until autumn; in the tropics year-round flowering is not uncommon — this may also be achieved by growing the plants in a glass case. They benefit, however, by a brief rest period in winter — about 2 or 3 months at a lower temperature and with limited watering.
The most important requirement in cultivation is plenty of direct sun or at least a position that is very little shaded. Airing is also beneficial, but must be restricted to the warm summer months; a sudden change in temperature may cause the plant to drop some of its leaves.
The growing medium should be a mixture of leaf mould, rotted turves, peat and sand, with leaf mould predominating. Alternatively, use John Innes potting compost No. 2. The plants should be watered liberally, except during the resting period, and given an application of feed every two weeks.
Other species are also lovely, but they are not commonly found in cultivation. Only in specialized collections may one come across A. neriifolia, yellow striped with brown inside, or the less robust A. violacea with purplish-violet flowers.