Why you should be growing Watsonia

Watsonias are rarely grown in the UK but deserve to be better known. Named after the eighteenth-century physician and botanist Sir William Watson, they were widely grown in the nineteenth century when they were first introduced to the UK from their native South Africa. However, their history goes back much further than this, with evidence that the corms were harvested and eaten by hunter-gatherers in Stone Age South Africa. Watsonias are members of the lridaceae (iris) family and, like their cousins crocosmia, they grow from corms that bloom in mid- to late summer. They also bear more than a passing resemblance to their other South African cousin, gladiolus, with their tall, willowy flower stems and strap-like leaves. Their flowers are more delicate than most gladioli, however, opening up from tubular buds to graceful trumpet-like blooms – giving rise to the plant's common name, the bugle lily.

One of the best places to see watsonia in the UK is on Tresco in the Isles of Scilly, where the plant has naturalised to produce its own 'Tresco Hybrids' in shades of pink, crim­son and orange. It can also be found in Abbotsbury subtropical gardens in Dorset, growing happily among other South African plants such as agapanthus and crocos­mia, and also around the margins of the Victorian lily ponds. In addition to the Tresca hybrids, which are now widely available to buy as plants or corms, there are several other species and cultivars available to grow in the UK, out of about 50 that grow in the wild.

W. pillansii produces sprays of lovely orange flowers from July to September and grows up to a metre tall, while its hybrid 'Stanford Scarlet' grows even taller and has rich orange-red flowers with dark indigo anthers. Other lighter colours of W. pillansii are to be found if you search around, generally known vari­ously as 'peach-flowered' or 'apricot form'. Another less widely grown species is W. borbonica, which has pale pink flowers, and the white form W. borbonica subsp. ardernei, which was discovered in 1888 and sent back to the UK, where it was cultivated in Kew Gardens. The cultivar 'Arderne's White' has unusually large white flowers, growing between 75cm and 1.2 metres tall.

How to grow watsonias

Watsonias can be tender and may not survive outside in cooler parts of the country, where they should be lifted like dahlias or gladioli and overwintered under glass. In areas with milder weather, they can be grown in a sheltered, sunny spot. in well-drained but moist. humus-rich soil. Planting them deep will help to protect them against frosts, and covering them with a thick layer of bracken, garden compost or any other organic mulch in winter provides added protection.

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