(Editor's Note: This article was originally published on March 23, 2008. Your comments are welcome, but please be aware that authors of previousy published articles may not be able to respond to your questions.)
Pulsatilla, pasqueflower or windflowers, are classic spring blooming perennials ideal for the front of the border or better still, in a rock garden setting. The common name pasqueflower comes from their blooming season, which often coincides with Easter (pasque being French, from word ‘paschal' or passover). In fact, a green dye from their flowers was traditionally used to dye Easter eggs! The Latin name is derived from the word ‘pulsa' which means to vibrate or shake, probably alluding to the plume-like seedheads that sway in the gentlest of breezes.
Pasqueflowers have been used for hundreds of years as an herbal medicine. The whole plant has a strong acrid taste. Despite this, they are eaten by both sheep and goats (is there anything they won't eat?!), though cows and horses will avoid them. As an herbal medicine, this herb has been used to treat a wide variety of health issues ranging from digestive problems, sleep disorders, eye problems, toothaches, headaches, earaches, vaginal yeast infections and upper respiratory infections. Pasqueflower even has antibacterial actions lending its use to treating skin infections.
As a genus, they have a temperate to sub-arctic distribution north of the Equator. Most of the 30 or so species are found in Eurasia with only 2 species extending into North America. They typically have finely dissected foliage, bell-shaped flowers in shades of purple and bright yellow stamens. They were once classified as Anemone, but are now separated based on their long-plumed seeds. The North America prairie crocus, Pulsatilla patens, is the State Flower of South Dakota and the Provincial Flower of Manitoba.
Most are alpines or inhabit wind-swept grasslands. In the former situation, the growing season can be short, so it is important for those Pulsatilla to bloom early. In the latter case, the plants need to bloom and set seed before they are crowded out by neighbouring grasses and other grassland wildflowers. The genus has a number of characteristics that allow for quick spring growth. The leaves and flower buds are extremely fuzzy. This helps reduce the force of wind over the plants, with the resulting trapped air actually becoming warmer than the surrounding air. The leaf surface temperature may be 10 degrees or warmer than the air, thus plants can start growth even when air temperatures are barely above freezing. In fact, it is not uncommon to see them flowering through the snow! When the plants first bloom, the flower stems are quite short (15-20 cm). This keeps the plants closer to the ground where the air is warmer than several feet above. The flowers are cup-shaped and act like a hyperbolic lense, directing the sun's warmth towards the center of the flower. This keeps the reproductive structures warmer than the surrounding air and also allows a warm feeding (and hence pollinating) area for visiting insects. The flowers even go so far as to follow the sun across the sky, keeping their faces into the sun for as long as possible. Once flowering has passed, the long, plumed seeds develop rapidly and the flower stems elongate considerably (between 30-60 cm). Being held higher into the air, these plumed seeds are better able to be caught and dispersed by the wind (hence the other common name ‘wildflower').
The main key to success is well-drained alkaline soil, full sun and minimal transplanting. Pulsatilla have deep tap-roots. This makes them very drought tolerant but at the same time, resentful of transplanting. If growing them, start with young plants and plant them where they will remain. They are generally long-lived plants. In areas with acidic soil, they benefit from a yearly dusting with lime. Their main killer is winter-wet so excellent drainage is imperative. Hardiness is not a problem as many are hardy to zone 3!
The flowers are certainly among the largest and most showy of the spring-blooming perennials, but the seedheads are also very attractive, providing additional garden beauty in early to mid-summer. Plants are generally grown from seed, rather than from divisions (remember they hate being transplanted). The long plumes should be removed from the seeds then the seeds are sown in fall, to spend a winter outside. Otherwise, stratify them inside in a refrigerator for 10-12 weeks to achieve maximum germination.
Probably the most common and easy species is Pulsatilla vulgaris, a western European native. This is the only species that exhibits enough natural variation that today, there are several named cultivars available. The standard species is mauve to purple but there is ‘Alba', white; ‘Rosea', light pink; ‘Eve Constance', reddish-pink; ‘Rubra' and ‘Rote Glocke' (aka ‘Red Cloak'), red; ‘Blaue Glocke' (aka ‘Blue Cloak'), dark purple-blue and ‘Papageno', a semi-double, frilled edge selection in mixed colours.
Some of the variation that exists among P. vulgaris. The last picture is the semi-double 'Papageno' series (courtesy of PanamonCreel)
Other species which look similar to the P. vulgaris are the eastern European species P. halleri (deep silvery-purple) and P. vernalis (nearly white with light purple-blue reverse) as well as the American species P. patens (variable purple shades). These are not as easy to cultivate outside their natural range and only a botanist can appreciate the subtle differences. For those living in the US mid-west or Canadian prairies, try to find P. patens var. flavescens which has light lemon-yellow flowers. Truly a beautiful variety.
Three other P. vulgaris look-alikes are P. vernalis, P. halleri and P. patens
The most spectacular and largest species is P. alpina ssp. apiifolia (aka P. sulphurea). This species has bright lemon-yellow flowers on stems that reach 60 cm or more. The spiky seedheads are the largest and most spectacular of any pasqueflower. The regular species is similar but has white rather than yellow flowers. It is native to alpine regions of central and southern Europe. The American counterpart is P. occidentalis, a difficult species that has smaller, white flowers and seedheads that appear to have had a comb-over!
Pulsatilla alpina ssp. apiifolia in bloom and in seed.
Pulsatilla occidentalis, growing in the Canadian Rockies
There are several other pasqueflower species that are sometimes offered in seed exchanges or by specialty alpine nurseries. These generally have smaller yet exquisite nodding flowers as well as the standard attractive seedheads. Among the easier to grow species in this group are P. albana (yellow, Caucasus region), P. bungeana (dark red, Altai region), P. georgica (pale silvery-lilac with bluish reverse, Caucasus region) and P. pratensis (dark reddish-purple; Europe).
Pulsatilla georgica has flowers about half the size of P. vulgaris while P. albana has perhaps the daintiest of blooms among the pasqueflowers.
For any gardener with a rock garden, the genus Pulsatilla is indispensable. For gardeners with more standard perennial gardens, pasqueflowers are a wonderful addition to the front of the border where their early spring flowers are a welcome sight after a long dreary winter.