Allamanda: Greenhouse Plants
W – warm, minimum of 13°C (55°F) / T – tropical, minimum of 18°C (65°F)
A group of tropical shrubs and, it should be possible to grow them with a winter minimum of 10°C (50°F) provided the plant is kept on the dry side and allowed to go semi dormant. Allamanda cathartica, the best known, is excellent as a climber trained permanently against a greenhouse wall or trellis. Beware though as this plant is going to need some headroom to grow at its best. Providing the temperatures are high (above 18°C, 65°F) it will bear its 8-cm (3-in) wide golden flowers almost continuously. The best method of training it is to encourage a framework of older shoots to develop over the trellis or wires (it is not self-clinging). Younger side shoots can be spurred back to within one bud of the older wood every spring, always cutting beyond a node. New shoots will then spring from the nodes and make new flowering shoots for the coming season. Cuttings can be made from the tips of shoots that are cut off at this time. Plants will definitely benefit from feeding in summer and winter but only if the temperatures remain high and the plant is in active growth. The variety A. c. ‘Hendersonii’ is mostly grown, distinguished by a white dot where each petal curves out. The petals are arranged in the windmill pattern common to all plants in the family. The only other species commonly grown is A. neriifolia which is more of a shrub than a climber. The flowers are smaller and more closed but still a good golden colour. This is more suitable if space is a problem.