Primula denticulata (drumstick primula)

Widely distributed from eastern Afghanistan and northern Pakistan, across the Himalaya to Yunnan, Sichuan and Guizhou in China.

Primula denticulata (Image: Richard Wilford)

Primula denticulata is a perennial, deciduous, clump-forming plant with compact heads of many flowers, and overwinters as large, above-ground buds with thick roots.

The winter buds of P. denticulata are surrounded by large, leathery scales. In spring and summer, the oblong, wrinkly leaves can grow up to 30 cm long and have a toothed margin. The spherical flower head is held on a stem up to 30 cm tall, is up to 8 cm across and composed of usually stalkless flowers. Flower colour varies from deep purple or blue, to pink or white but the normal colour is pinkish-purple or lilac, with a yellowish eye.

Primula denticulata subsp. sinodenticulata, from north Burma and west China, is a robust plant with an elongated flower stem, up to six times the length of its leaves.

The closely related species P. cachemeriana (syn. P. denticulata var. cachemeriana), from Kashmir, is sometimes seen in cultivation but it is not widely grown. It differs from P. denticulata in its pointed, yellow-mealy (with a powdery coating) resting bud and the narrow, very mealy leaves, which remain smooth until after the plant has flowered. Some authors classify this as a form of P. denticulata but Professor John Richards, a former chairman of the Alpine Garden Society and author of the monograph Primula, retains it as a separate species.

Primula denticulata is cultivated as an ornamental.

Primula denticulata is an easy, hardy garden plant that can be grown in a variety of soils but will not tolerate drying out in the summer months. It thrives in heavy garden soil in a border and is ideal for small gardens. It also does well in dappled shade.

It is a clump-forming species that can be propagated by division in summer or autumn. Fresh seed can be sown from autumn to early spring. Root cuttings can also be taken when the plant is dormant.

Primula denticulata can be seen in the in the Rock Garden at Kew and at Wakehurst. Other species of primula found in the Rock Garden and the Alpine House at Kew include Primula beesiana, Primula bulleyana, Primula verticillata and Primula vialii.

Spirit-preserved, as well as pressed and dried specimens of Primula denticulata are held in Kew’s Herbarium, where they are available to researchers, by appointment. The details, including an image, of one of these can be seen on-line in the Herbarium Catalogue.

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Curtis’s Botanical Magazine (Wiley-Blackwell)