Pulsatillas for the rock garden

Taxonomy and distribution

Some authorities insist on including Pulsatilla in the large and complex genus Anemone. However, the majority opinion of botanists and gardeners is that they are best regarded as a distinct yet closely allied genus.

The genus contains 36 species with a distribution that encompasses much of the temperate regions of the Northern Hemisphere except for the east half of North America. The species are predominantly plants of mountainous regions. They grow in meadows and rocky places to over 3000m in parts of the Alps and the Rockies.

The species and cultivars come in a wide range of colours from white to yellow, pink, purple, red and green, even black. The centre of the flowers is filled with a mass of golden anthers.

Growing Pulsatillas in the rock garden

Those available to the gardener are not difficult to grow. They are best purchased as young pot-grown plants and once planted left to mature. Established plants greatly resent being moved. Pulsatillas can be grown in the flower border or, better still, in a rock garden. They will also grow very well in raised beds or in a trough. All require an open sunny site and well-drained neutral or alkaline, gritty compost. Once established they will reward for years to come and will self-sow around delightfully in some gardens.

The garden pulsatilla is basically derived from three, primarily European species. The common pasque flower, Pulsatilla vulgaris is native to southern Britain and Western and north-western Europe. Pulsatilla grandis hails from Central Europe while the alpine Pulsatilla halleri is scattered in various subspecies from eastern France to the Balkans. In fact, many plants grown, apart for the genuine species, are hybrids between these species, particularly the first two.

Growing pulsatillas from seed

For best results sow Pulsatilla seed the moment it is ripe or shortly afterwards. Fresh-sown seed generally germinates in 3-4 weeks. Any good well-drained compost such as John Innes seed compost with a little extra grit added will suffice. Sow in pots or pans, cover with a thin layer of additional compost and top with a layer of grit. This helps prevent the compost below drying out. There is no need to remove the feather seed tails. It makes no difference to germination whatsoever. Thin sowing is wise. Once germinated the young plants can be pricked out easily once they have developed two or three true leaves.

Summer-sown seed should give some good sturdy young plants by the autumn. These are best overwintered, like the seed pans, in a cool shady frame or greenhouse until early spring when growth commences, then they can be planted out in the open garden. Pulsatilla vulgaris and its close allies and hybrids are easy and fast from seed (they will often flower in their second year).

Unfortunately, this is not true of the stately and beautiful Pulsatilla alpina group. With species primarily in the mountains of Europe and the Caucasus (Pulsatilla aurea) and western North America (Pulsatilla occidentalis) they have proved notoriously slow to develop into good-sized plants in the garden. They also take a number of years before flowering with any enthusiasm. The last two named in fact are almost impossible except in the confines of a well-managed alpine house. With exquisite deeply cupped flowers in white, cream or yellow, the various forms of Pulsatilla alpina are a great delight and well worth persevering with. To see some old clumps flowering with ease in the garden is exciting and a great tribute to the gardener.

Pulsatilla cultivars

When selecting plants for the garden by far the best time is when they are in flower. At this time the best colours and forms are easy to pick out. While many plants sold in garden centres and nurseries are of mixed or uncertain origin there are some exciting cultivars to look out for and these include:

• ‘Alba’: attractive white flowers but quite variable.
• ‘Barton’s Pink’: flush pink flowers; comes true from seed.

• ‘Blaue Glock’ (‘Blue Clock’): lilac-blue flowers.
• ‘Eva Constance’, (a selection of the closely related Pulsatilla rubra): velvety red flowers on a neat little plant.
• Heiller Hybids: A Jellito (Germany) selection of good robust, upright plants with flowers in a full range of colour.

• ‘Papageno’: sumptuous and vigorous plants with half-nodding semi-double flowers in a wide range of colours, reds and purples being especially attractive.
• ‘Perlen Gloche’ (‘White Bells’ or ‘White Clock’): lovely upright bells of purest white with a slight green flush towards the base of each petal.
• ‘Rosea’: rose-pink flowers.
• ‘Rote Glocke’ (‘Red Clock’): upright flowers of deep red appearing with the young foliage.
• ‘Rubra’ (sometimes as var. rubra): very appealing flowers of rich red to carmine red, rather variable in size but one of the best.

• ‘Watermelon Pink’: large open bowls of soft pinkish red. A fine American selection.
• ‘Weisser Schwan’ (‘White Swan’): ascending white blooms, which are particularly large.

In addition, various seed ‘Strains’ are available from seed merchants and nurseries.

Dr. Christopher Grey-Wilson

The author photographing Aquilegia transsilvanica in the Carpathians

Christopher (Kit to friends) retired as Editor of the Alpine Garden Society’s Journal in 2011. Before that, from 1968-1989, he was a Principal Scientific Officer at the Royal Botanic Gardens Kew. He has travelled widely in the mountains of Europe and Asia, in particular. Over the years Christopher wrote more than 30 books and many articles. Clematis, Cyclamen, Meconopsis, European alpine plants, Greek bulbs, Mediterranean flowers and poppies are among his favourite subjects. He was awarded a VMH by the RHS in 2007 for ‘outstanding service to horticulture’.