Tropical plants and fruits add a sultry air to British gardens. Here is how to grow exotic species of plants and flowers in our temperate climate.
Hedychiums – Ginger Lily
Hedychiums are among the most reliable and colourful of exotic plants and can be used as eye-catching centrepieces in sheltered borders. The ginger lily (Hedychium forrestii) has hardy roots that can withstand cold and grows up to 6ft tall, with bottlebrush-like clusters of white flowers in August and September.
H coccineum ‘Tara’ is slightly smaller and has fragrant orange flowers in the early autumn. If you prefer yellow flowers, use the deliciously perfumed H gardnerianum. In mild gardens, the national flower of Cuba, H coronarium (butterfly ginger) is worth trying: it produces highly fragrant white summer flowers, resembling butterflies on the wing, held above lush, lance-shaped leaves. In a warm summer, the flowering stems can reach 5ft tall – http://www.devonsubtropicalgarden.co.uk/page18.htm
All hedychiums thrive in sun or partial shade, need plenty of moisture and benefit from a liquid feed every fortnight in growing season. In the autumn, the first severe frost will knock the plants back — the leaves and stems should then be cut down to ground level. Afterwards, spread a thick mulch of bark chippings over the soil surface to act as winter insulation. In cold and exposed gardens, it is safer to raise hedychiums in 12in containers filled with John Innes No 3 compost, so they can be moved into a greenhouse or conservatory for the winter. Keep the compost on the dry side.
If you want a leafy jungle feel, it’s hard to beat ornamental bananas. The toughest of all is Musa basjoo (Japanese hardy banana), which has lance-shaped bright green leaves that arch outwards and upwards from the top of a main stem or trunk. Growing up to 10ft tall, it can even fruit in milder areas. Ensete ventricosum (Abyssinian plantain) is also worth a gamble in mild areas for its huge green and purple paddle-shaped leaves, although it performs best as a conservatory plant — don’t expect it to fruit outside. The key to a banana’s survival is exposure to sunshine, shelter and well-drained soil: strong winds shred the leaves and continual “wet feet” in the cold months spell disaster.
In late autumn and winter, the main stem and crown of a top banana (don’t bother with the leaves) need protecting with bubble wrap or straw, with an added layer of fleece, or the plant may die back to ground level. If this happens, don’t despair: bananas usually resprout from the base. In the middle of spring, remove the protection when new shoots emerge and give the plants copious amounts of water between May and September. Cautious gardeners can grow the plants in a large container and pop it indoors before the frosts arrive.
The pineapple guava (Acca sellowiana) has sweet-tasting egg-shaped fruits (Marianne Majerus) Alocasias and colocasias are tropical perennials grown for their enormous, vibrant leaves: they make a great backdrop to flowers. The former produce clumps of heart-shaped dark-green leaves, up to 3ft in length, adorned with prominent white veins, and require lots of moisture in summer. Colocasias (elephant’s ear or taro) grow faster and add drama to a garden border, particularly ‘Black Magic’, which has sumptuous purple leaves.
To ensure survival, keep the plants in containers and move inside in winter. If you live in a mild spot, and are feeling brave, plant alocasias and colocasias in a sunny, sheltered corner with a well-drained soil and cover the ground with a thick winter mulch, then spray occasionally in summer with tepid water. With a little luck, the plants will return the following year.
Those gardeners who want a real taste of the tropics could try growing plants with edible fruit. The pineapple guava (Acca sellowiana), an evergreen shrub with grey-green leaves, curious peeling bark and magnificent crimson and white summer flowers, has sweet-tasting egg-shaped fruits. For a good crop, restrict this plant in a large container, such as a half-barrel, stand it outdoors in the summer, then move back into a conservatory as soon as flowering stops in the late summer. If you don’t do this, a cold spell in the early autumn will ruin the developing fruits. This tropical beauty can also be grown as a hardy garden shrub (full sun, shelter and a well-drained soil are essential), but any fruits are unlikely to reach maturity.
The Cape gooseberry
The Cape gooseberry (Physalis peruviana or P edulis), a perennial with smooth-skinned, cherry-size orange fruits and a papery husk, has become a common garnish in restaurants. It is simple to grow: use a 15in diameter container filled with compost and keep in a greenhouse in winter, then on a sunny terrace in summer. To grow from seed, sow in early spring and harvest between now and early October. During the main growing period, water the plant often, feeding every 10 days when the starry yellow flowers appear and supporting it if necessary. In late summer and early autumn, gather the sharp-tasting fruits as the husks turn brown and peel away from the base. You can eat them raw or use them for jam.