Pasque flower

Three separate plants are sold and photographed under this one name. The European pasque flower, Pulsatilla vulgaris, is the garden plant of American benches and rock gardens, sold in places under its old name Anemone pulsatilla. The North American prairie plant is the wild one, filed under both Anemone patens and Pulsatilla patens. Its range runs from near Lake Michigan to the Northwest Territories and south to New Mexico, and in the United States from Idaho to Wisconsin down into Utah and Colorado. The third is the western pasque flower, Pulsatilla occidentalis, a white-flowered mountain plant of ground from British Columbia to California and east to Montana. All three get shuffled between Pulsatilla and anemone, two genera so close that the European plant still turns up under the second.

The split matters at the till. The prairie plant is seldom grown as an ornamental, and it gets confused with the European species that is. An order under the shared name sometimes arrives as the European or the western plant. The two grown as ornamentals take different amounts of cold, want different amounts of water and flower in different months. A label carrying only the words pasque flower settles none of that, so the line worth reading is the binomial.

South Dakota's state flower is the American prairie plant. The state named it in 1903, under the older binomial Pulsatilla hirsutissima, and the same prairie species grows wild in seventeen other states and Alaska. The European garden species holds no such title anywhere. It is also the plant most often sold under the shared name, and that is the root of the mix-up. Pasqueflower is also the provincial flower of Manitoba, and members of the genus are county flowers for Hertfordshire and Cambridgeshire in England and for Oppland in Norway.

The colored cup is not made of petals. Pasque flowers have no petals at all, and the violet parts are sepals. On the prairie plant they number six to eight, joined at the base and running from deep blue to purple. Inside sits a dense boss of 150 to 200 yellow stamens around a bundle of pistils. Flowers on the European plant open 1 to 3 inches across, carried singly. On the prairie plant they measure 20 to 40 millimeters long. Color runs past violet to cream, tan, lavender and white.

The silver look is hair. Very long silky hairs cover the sepals, the stems and the dissected leaves. They are on the buds before the flowers open and on the seed heads afterward, and they gave the plant the name prairie smoke. The Blackfeet name Napi, old man, points at those gray silky heads, and the seeds leave on the wind or in the fur of an animal walking through. In Canada the plant is prairie crocus, for its likeness to a true crocus, and hartshorn-plant and gosling were in use before the 1920s. Juice from the purple sepals leaves a stain that washes out, and it has colored Easter eggs in parts of Europe. The look-alike that catches gardeners out on the European species is clematis.

It opens with the thaw, and the month depends on the species and on how high the ground is. The prairie plant flowers March to April, the European plant April to May. Across its elevation range, from 330 to 12,500 feet, flowering runs from April through August. One calendar cannot cover that: a mountain meadow at the edge of a snowfield keeps nothing like the dates of an open hill prairie.

The trigger is snowmelt, and the flowers do not wait for settled weather. They often emerge as soon as the snow melts, may then be snowed on again, close up in colder weather and reopen when it warms. Buds that come up furred and shut beside a shrinking crust of old snow are behaving normally. Coming out this early is the point of the plant in a garden, since these are among the first blooms of the spring.

Full sun to light shade, and ground that drains hard. Both garden species take that same light, and the difference between them is moisture. The European plant wants fertile, humusy, gritty soil of medium moisture, with drainage the one condition that cannot be missed. The prairie plant takes the same grit kept drier, dry to medium, and it tolerates drought, dry soil and shallow rocky ground. The European plant turns quite drought tolerant once it has settled in. In the wild the genus grows in grassland over alkaline, limestone soils, on deep tap roots. Aim for neutral to slightly alkaline ground, between about 6.8 and 8.0.

Wet ground is what the siting advice is written against. In a moister climate, plant on a slope, a hillside or a raised bed, so the roots are not standing in waterlogged soil over winter. This is a plant that loves cold weather and a poor choice for the southern half of the country. Established plants are best left undisturbed, and the reason is underground: the tap root goes deep, and a plant built on that root resents being lifted.

Dig the hole in the place the plant is going to stay. No depth or spacing figure is published for a potted pasque flower. What matters is the root: lift the plant with a substantial amount of soil around it, and size stops mattering. Young seedlings take a move better than settled plants do, and neither is easy. A plant on a long deep tap root resents being lifted and is better left alone.

An established plant can be moved, with a condition attached. Cut it back hard first, and it should regrow and rebloom in about 4 weeks. Take off all the open flowers and large buds before you lift it. Division is the other way to get more plants, and one mature clump divides into 4 to 6, alongside seed and root cuttings. Given how deep that tap root runs, division has the most to lose.

Whether the seed needs a cold period depends on how old the seed is. Fresh seed germinates readily with no pretreatment, in about 3 weeks or a little more. Seed that has been dry stored for months behaves differently. It goes into deep dormancy and germination turns variable. It takes about 60 days of cool moist stratification before it will sprout, then germinates at 65 to 70 degrees Fahrenheit. The way around that dormancy is to sow outdoors in fall and let the freeze and thaw cycles do the work. A full winter of cold moist conditions suits stored seed, the longer the better.

A seedling is a multi-year project. Flowering begins after several years at the earliest, and the first flowers come at two or three years of age. Until then there are hairy divided leaves and nothing above them, which is worth knowing before a flowerless patch gets dug up and replanted. From seed the species is somewhat difficult in general.

Most of the yellowing on a settled pasque flower is the plant going quiet on schedule. The foliage holds through the summer, and the leaves may die back late in it. Later in the year the plant can go dormant as a normal part of its cycle. Drought pushes the same switch, since the prairie species may go dormant when the ground runs dry. Winter takes the leaves off entirely, because this is an herbaceous perennial that spends the cold months as a root, with new leaves up in early spring before the flowers. A clump that is bare in late summer and again through the winter is doing what it should.

The fault to look for is standing water. What the plant needs above all is good drainage, in soils that run moist to dry. The two garden species do not take the same water: dry to medium for the prairie plant, medium for the European one. So the question in front of a yellowing clump is what the ground has been doing. Dry ground under a plant that flowered in spring points at the yearly cycle; soil that has stayed wet over winter does not.

Nothing on this plant needs cutting once a year. Take off the open flowers and large buds before you move a plant, or leave the seed heads standing to disperse. The leaves may die back on their own in late summer, and winter takes the rest, since the plant spends the cold months as a root. The warning that a hard cut can kill a pasque flower comes from a plant care app, which puts the limit at 15 to 20 percent of the plant at one time. No horticultural guidance for the species repeats it.

It makes a clump and stays where it is put. The prairie species grows from a substantial underground tap root and can also reproduce vegetatively. New rosettes come up from its vertically branched roots, so an old plant thickens into several crowns of the same individual. Seed is the other route, and a short-lived one, since the seeds do not persist in the soil. A seedling appears in the season after the seed falls, or the chance is gone. No runner, no colony, no edge that has to be cut back.

Every part of a pasque flower is poisonous while it is fresh. Behind that is protoanemonin, a bitter oil carried by many species of the genus, and an estimated 30 fresh plants eaten is a lethal amount. On the European garden species, eating any part causes severe pain in the mouth, and serious poisoning follows large quantities. Fresh sap inflames and blisters skin on contact, and swallowing it brings vomiting and diarrhea. The western mountain species carries the identical warning, poisonous in all parts when fresh. That makes gloves worth wearing when you cut or divide a plant.

Drying changes the hazard. Protoanemonin breaks down quickly into a harmless compound once the plant is dried, so the caution belongs to the fresh plant. For pets there is no direct answer. The ASPCA's toxic and non-toxic plant list has no entry for pasque flower, none for anemone and none for windflower. That list is a compilation of the plants most often encountered, and not all-inclusive, so an absence there settles nothing about this plant.

The plant has a long medical history. The US Forest Service calls pasqueflower a powerful healing agent, used in small amounts by Native Americans and settlers for various ailments. The uses are specific: dried leaves as a tea for rheumatism, a poultice of pressed dried leaves on the skin, and pulverized roots against lung disorders. The European species carries the same kind of note as an herbal medicine, and the flowers served Native Americans as medicine for centuries.

The modern uses have no clinical evidence behind them. Homeopathic pulsatilla is used for sore nipples and mastitis, and to reduce or increase a milk supply, and no scientifically valid clinical trials support any of it. The chemistry explains why the old accounts all describe the dried plant. Pulsatilla contains ranunculin, protoanemonin and anemonin, along with triterpene saponins and flavonoids. The fresh plant is extremely irritating to the skin, the gastrointestinal tract and mucous membranes, and allergic reactions are reported. Never swallow the fresh plant. The medicinal use in the old accounts belongs to the dried one.

Labels split by species before a cultivar name is printed, so the two species come first. Every cultivar below is a selection of the European plant, the one most often on a bench of spring garden flowers.

Pulsatilla vulgaris, the European species

European

Also sold as Anemone pulsatilla
Bell shaped flowers, 1 to 3 inches
Hardy in zones 4a to 8b

Anemone patens, the prairie species

North American native

Also filed as Pulsatilla patens
South Dakota's flower since 1903, as Pulsatilla hirsutissima
Hardy in zones 3a to 8b

'Alba'

White

Creamy white flowers
Sometimes sold as White Bells or White Swan
Slower and later than the species

'Rote Glocke', Red Bells

Red

Red flowers in the Glocke series
One of three Glocke selections offered together

'Rosen Glocke', Rose Bells

Rose pink

Rose pink bells in the same series
Also sold as Pink Bells

'Perlen Glocke', Pearl Bells

Palest pink

Very pale pink flowers, part of the Glocke series

'Blaue Glocke', Violet Bells

Violet

Violet flowers, also written Blau Glocke, one of four in the series

'Prima Papagena'

Semi-double

Fringed to semi-double flowers
An improved 'Papageno', released 2018 by Jelitto Perennial Seeds

'Rubra'

Wine red

Wine red flowers on the European plant

Pulsatilla vernalis, spring pasque flower

Evergreen leaves

White flowers with a bluish purple reverse
Evergreen leaves, hardy to zone 4a
Native to alpine Europe and Siberia

Pasque flower is small, and nothing published makes it wide. The European plant is about a foot each way, 9 to 12 inches tall and as much across. The prairie plant runs 3 to 12 inches tall with a spread of 3 to 6 inches, and its taller measurements reach 16 to 24 inches. Where a label names no species, the height printed is about 10 inches.

Season is part of the reason they differ. The prairie plant's spring height reaches 17 inches. On the European plant the flower stems stand 5 to 8 inches tall, with the leaf mound behind them at 10 to 12 inches. A plant measured with its flower stems up, and the same plant measured later as a mound of leaves, will not give the same number.

Pasque flower opens when almost nothing else is out, and that timing is most of its value to wildlife. The flowers are good for pollinators, and the prairie plant is cross-pollinated by honeybees, solitary mining bees, bumblebees and hover flies. Grazing animals are a different case. The prairie plant is mildly toxic from its protoanemonin content, its forage value to herbivores is low, and a grazed plant answers by producing new leaves from dormant buds. On prairie ground it is adapted to disturbance, wildfire included, and its numbers increase in heavily grazed meadows.

Pasque flower belongs at the front of a perennial border or in a rock garden, where it combines well with spring-flowering bulbs and ground covers. Anything beside it has to take full sun and gritty ground that drains hard, and it has to stay off the crown of a plant that dislikes being disturbed. The bulbs it is asked to share a bed with, snowdrops among them, come and go on the same early clock. Plants that fill a similar niche to the European species are Anemone blanda, Anemone hortensis 'St Bavo' and Viola sororia.

1. The newest naming puts a trap in the label. Under the treatment that splits the two, true Pulsatilla patens is native only to Europe, Russia, Mongolia and China, and the American prairie plant becomes Pulsatilla nuttalliana. A label reading Pulsatilla patens no longer says which continent the plant came from.
2. A plant code settles what a common name cannot. The federal code for the North American prairie pasqueflower is PUPA5, filed under Pulsatilla patens and marked native to the Lower 48, Alaska and Canada. It is the fastest way to check that a plant sold as native is the prairie species.

Related Guides & Flowers

Hellebore

The other perennial that flowers while the ground is still cold, for the shadier end of the same season.

Gentians in rock gardens

Alpine neighbors for the same gritty, sharply drained bed.

Purple flowers

Where the violet cup sits among the other purple flowers of the garden year.

Spring plants that vanish by summer

The gap left by a plant that finishes early, and how gardeners plan around it.