Given conditions which emulate those of its native habitat, this member of the Acanthaceae family will do well in the home. Unfortunately, the environment of tropical Africa is difficult to recreate indoors, so the rather splendid Whitfieldia longifolia has to be regarded as a short-term flowering houseplant, and it is normally discarded after the flowering period has come to an end. If this plant can be grown in a conservatory or garden room, and provided with warm and humid conditions all year through, then it should be possible to keep it for more than one season; mature and established examples may reach 2.4m (8ft).
This particular specimen has attractive white flowers, however, red-flowered types are also available. The erect spires of blooms appear above the large glossy leaves.
The tropical Whitfieldia longifolia needs warm conditions to grow well: in Summer, provide a minimum temperature of 13°C (55°F), the preferred temperature range being 20°C (68°F) and above. Plants that are to be overwintered should be kept cool for the month following the end of flower production.
Grow Whitfieldia longifolia in good, bright, but indirect, light; full sunlight may prove too strong and scorch the foliage.
Using tepid water, water this plant well, then allow the surface of theto begin to dry before the next thorough watering: do not allow the roots to dry out when the plant is in bloom. Long-term plants should be rested for about four weeks after flowering by reducing both the amount of water given and the growing temperature.
Whitfieldia longifolia requires a high degree of humidity to thrive: do not mist the flowers, but increase the level of humidity in the plant’s vicinity by standing it on a tray of moisture retentive pellets.
Feed this plant every fortnight from the end of the rest period through to the appearance of the flowers: use a general-purpose house-plant feed. Specimens used as short-term houseplants will need no feed.
Grow Whitfieldia longifolia in a free-draining, loam-based compost: if necessary, repot at the end of the plant’s rest period. Any excessively large stems, or straggly growth, should be pruned away at the same time.
This plant would be ideal for Summer impact in a – lightly-shaded fireplace, or when used with a rich array of green. The combination of white and green always provides a display with an air of distinction.
Whitefly may be a problem: they lurk on the crinkled undersides of the leaves and rise in clouds when the plant is disturbed. Control these pests by using a suitable insecticide.