Tuesday, December 1, 2015

Incarvillea delavayi

Pride of China, Hardy Gloxinia, Chinese Trumpet Flower, Garden Gloxinia

This beautiful clump-forming perennial is excellent for rock gardens and borders. It has handsome foliage and upright stems bearing large, trumpet-shaped, usually bright pink, flowers in early summer. It grows to a height of 60 cm with a spread of 30 cm, but dies down early in autumn. It is frost hardy, but should be protected with mulch during cold winters. It makes an excellent talking point in the garden.

Incarvillea is a beautiful flowering plant with low growing clumps of glossy, deeply divided leaves from which arise 25cm - 50cm leafless stems topped by clusters of flowers, each flower may be up to 75mm across. The first few blooms on each plant often appear before the rosettes of mid-green leaflets have fully developed. 

Blooming from late spring to midsummer, the large terminal heads of exotic trumpet-shaped flowers are a bright magenta to rosy-pink, with yellow throats and are held well above the rosette of dark green foliage on stout stems. ‘Alba’ and 'Snowtop', are white-flowering varieties.

The fleshy taproot must have excellent drainage as they do not tolerate wet or waterlogged soil in winter and grows best in a rock garden or raised bed in a position that receives some sun every day. Remove faded flowers to encourage more buds. Excellent for cut flowers.

Sometimes it is best to treat them as short-lived perennials but it is well worth the extra effort to grow these plants.

The crowns are easily damaged and plants are very late to emerge in the spring, Do not disturb them and you will be rewarded with exotic looking flowers each spring. Grow Incarvillea in deep, sandy soil that has been liberally enriched with compost. They need consistent moisture while in bloom. 

Protect the young growth from slugs but otherwise no major problems.

Crowns should be buried 75-150mm below soil level in a area with full to part sun that is protected. Plants should be mulched in autumn with dry straw or some other mulch, to protect the crowns from winter damage.

Seeds may be sown in the spring or autumn in sandy soil in a cold frame or they may be sown in trays of soil outdoors and covered with sheets of glass. Seeds need no pretreatment but need light to germinate. Do not cover them with soil. Seeds take about 14 days to germinate with soil temp at 10-15° C. Propagation can also be by very careful division in spring but mature plants do not like disturbance.

The genus Incarvillea belongs to the family Bignoniaceae and consists of 17 species native to central and East Asia, including the Himalayas. All are suitable for rock gardens and borders. Some species are annuals, although those in cultivation are usually perennial. Some of the shorter growing species from higher altitudes of the Himalaya’s, Tibet, India and Turkestan have the largest and most exotic flowers. Most species flower in shades of magenta and deep rose-pink although one or two species come in shades of yellow or white. Unlike most other members of Bignoniaceae, which are mainly tropical woody plants, species of Incarvillea are herbs from temperate regions. Incarvillea is named after the French Jesuit missionary and botanist Pierre Nicholas Le Chéron d’Incarville.

The most commonly grown species is  Incarvillea delavayi.

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