Pulsatilla nuttalliana (DC.) Spreng.

Flowering Timing

Pulsatilla nuttalliana (DC.) Spreng. produces flowers before its foliage develops, blooming while leaves are just starting to emerge.

Flower Stalk Characteristics

The stalk holding the flower may be quite fuzzy or nearly smooth, but it is never completely hairless.

Bract Structure

Below the flower head, a ring of three highly divided bracts surrounds the flowering stalk, and these bracts are very different from the plant’s leaves.

Flower Arrangement

Each flower grows at the end of an individual stalk, and a single plant may produce either one or many flowers.

Sepal Color and Count

Flowers have five to eight lavender, blue-purple, or sometimes pale or nearly white sepals. Plants that bear flowers with higher numbers of sepals will typically revert to the more common six sepals in future years.

Flower Shape and Size

Petals are oblong to elliptic in shape, and flowers face upward like bells, measuring 20–40 mm long.

Flower Center Structure

The center of the flower is bright yellow, with a cluster of 150–200 stamens surrounding numerous styles.

Blooming Season Timing

The blooming period is very early; flowers often emerge as soon as snow melts, and may be covered by snow again afterward.

Temperature Response of Flowers

Flowers close during cold weather and reopen when temperatures warm.

Achene Structure

After blooming, fertilized flowers develop dry fruits called achenes, each with a feathery 20–40 mm long “tail” formed by the growing style.

Style and Seed Characteristics

Fertilized styles change color from whitish to pink or pink-brown, and each achene holds a single seed.

Seed Head Appearance

The entire seed head looks like a shaggy ball of threads.

Post-Flowering Stalk Growth

The stalk continues growing after flowering, moving the seed head far above the leaves and leaving the ring of bracts much lower down.

Pollination Mechanisms

Flowers can produce seed through either cross-pollination or self-pollination, and they exhibit protogyny (female parts develop before male parts) to encourage outcrossing.

Plant Type and Mature Height

Pulsatilla nuttalliana is a herbaceous perennial plant that reaches 5–40 cm in height at maturity, rarely growing as tall as 60 cm.

Stem Characteristics

Its stems are soft and covered in short, fine hairs.

Basal Leaf Structure

Basal leaves are ternately compound (divided into three parts), and each leaflet is further subdivided, resulting in end segments 2–4 mm wide.

Terminal Leaflet Attachment

The terminal leaflet attaches to the leaf stalk via a very short stalk or is almost completely sessile.

Full Leaf Dimensions and Shape

The full leaf has a teardrop or obovate outline, and measures 3–5 cm wide, rarely as narrow as 2.5 cm.

Root System and Vegetative Reproduction

The plant grows from a large underground tap root, and can also reproduce vegetatively by growing new rosettes from its vertically branched roots.

Natural Habitats

Natural habitats for Pulsatilla nuttalliana include cool northern prairies, open slopes, fescue grasslands, forest granite outcrops, and dry open woodlands in montane and boreal regions.

Anthropogenic Habitats

It also grows in human-created habitats such as clearcut areas, roadsides, and the edges of gravel pits.

Canadian Distribution

Pulsatilla nuttalliana is widely distributed across North America, ranging from Alaska (U.S.) and Nunavut (Canada) east to Ontario and across all western Canadian provinces.

US Distribution

In the U.S., it grows from Idaho east to Wisconsin, and south to Utah, Colorado, and parts of New Mexico, covering all upper Midwestern states and the Northern and Southern Rocky Mountains.

Global Conservation Status

NatureServe lists it as globally secure, but also classifies it as a subspecies rather than a full species.

Regional Conservation Status

It is assessed as critically imperiled in Washington, Illinois, and Ontario.

Pollinator Species

Pulsatilla nuttalliana is cross-pollinated by a range of insects including honeybees, solitary mining bees in the family Andrenidae, bumblebees, and hover flies.

Seed Dispersal Methods

Its seeds are dispersed by wind, or when they catch on the fur of passing animals.

Herbivore Forage Value

The plant has low forage value for herbivores because it is mildly toxic, containing protoanemonin.

Grazing Response

If grazed, it will grow new leaves from dormant buds, and populations of Pulsatilla nuttalliana increase in heavily grazed meadows.

Disturbance Adaptation

It is adapted to habitat disturbances including wildfire, but its seeds do not persist in the soil in significant quantities.

Ornamental Cultivation Context

Pulsatilla nuttalliana, also called prairie pasqueflower, is rarely grown as an ornamental garden plant, and is often confused with the commonly cultivated European species Pulsatilla vulgaris.

Ornamental Uses

It is still a useful ornamental, especially for gardeners interested in North American native species. It is planted somewhat more often in gardens designed to resemble an Upper Midwest prairie, in rock gardens, and for its value as spring forage for bees.

Fresh Seed Germination

Fresh seed of Pulsatilla nuttalliana (and other Pulsatilla species) germinates easily without stratification or other pretreatment, sprouting in about three weeks or slightly longer.

Stored Seed Germination

Dry-stored seed that has been stored for several months requires 60 days of cool moist stratification, then sprouts at 18 to 21°C.

Seed Storage Requirements

Seeds do not store well, so they should be planted immediately or kept in cool dry conditions.

Vegetative Propagation for Cultivation

Pasqueflowers can also be propagated vegetatively for gardens or habitat restoration by taking 2–4 cm root cuttings and planting them in well-drained potting medium.

Transplanting Guidelines

Seedlings are difficult to transplant, and transplanting any size of this plant requires avoiding root disturbance by digging with a large amount of surrounding soil.

Garden Soil Drainage Needs

Good drainage is critical for the health of garden-grown prairie pasqueflower.

Preferred Garden Soil Conditions

It grows best in moist to dry soils with a neutral to slightly alkaline pH (7.0 to 8.0) and winter snow cover.

Winter Hardiness

It is winter hardy in USDA zones 3–5.

Compost Tolerance

Unlike some wildflowers, it grows well when 7 centimeters of compost is added to the topsoil.

Light Requirements for Hot Climates

In regions with hot summers, the plant experiences less stress with partial to half-day shade.

Light Requirements for Cool Climates

In regions with cool summers such as mountain habitats and northern prairies, it requires full sun.