Expert advice on houseplants and alpines
Most of us are familiar with bedding impatiens, but you can also grow some as houseplants
Impatiens are a large family of plants with hundreds of species of annuals and perennials growing in tropical and sub-tropical regions all around the world, mostly in mountainous areas. Most species grow beside streams in semi-shaded areas in conjunction with ferns and mosses.
The common feature of these plants, and the reason they're commonly referred to as ‘touch-me-not’, is the explosive nature of the seed capsule – ripe capsules will burst open shooting their seeds in all directions away from the parent plant.
Many of the lesser-known species make excellent houseplants; there's a wide variety of growth habits within this family comprising upright, shrubby, trailing and procumbent (grows along the ground without producing roots). These varieties need as much light as possible during the winter and generally a minimum temperature of 12C (54F). Reduce watering in the autumn and only increase it when the temperatures rise in the spring.
Impatiens repens
This is a Sri Lankan species with a creeping habit. Stems are red in colour, succulent and grow procumbently, up to 50cm (1¾ft) in length. During spring and summer it's covered with large, yellow flowers. This variety needs warmth and moisture in the summer, at least 20C (68F) during the summer; during the winter keep at a minimum of 16C (61F). The stems are quite brittle and can break off if moved; propagate new plants from any broken sections.
Impatiens niamniamensis
An exotic-looking species, commonly called parrot plant or Congo cockatoo due to the intense red and yellow-coloured spur. This is an upright variety with thick, succulent stems. The brightly coloured flowers mostly form directly off the main trunk of the plant and sometimes can appear hidden under the foliage. Keep warm during the summer, 20-26C (68-79F), but excessive heat can cause the plant to become pale and lose vigour.
Make more plants
It's easy to propagate new impatiens plants from stem cuttings. Use young, soft growth which is about 10-12cm (4-5in) in length. Remove the cutting using a diagonal cut across the stem (this increases the open surface area). Remove the lowest leaves and place the cut edge of the stem 3-4cm (1-1½in) deep into good compost in a small pot, 7.5cm (3in) in size. Lightly dampen compost and seal the whole pot in a clear bag or propagator; this is essential as it helps to maintain a high humidity around the leaves. Place the pot in a warm, light position but not in direct sunshine. Ideally take cuttings when parent plants are growing rapidly and it's easy to keep cuttings warm, about 20-22C (68-71F). They should root within four weeks and over the following two weeks gradually open the bag or propagator to allow the young plants to become acclimatised to normal, lower humidity levels.
Impatiens niamniamensis variegated
This is a variegated form of I. niamniamensis and is commonly called golden cockatoo; it has the same habit but with the addition of bands of golden variegation on the edges of all the leaves. A very flamboyant variety.
Impatiens kilimanjari pseudoviola
This variety has small leaves and a trailing habit that makes it a suitable choice for a hanging basket; very free flowering with small, glowing pink flowers.