Blazing Stars (also called Gayfeathers) of the Liatris genus have general characteristics of: Stem leaves narrow and lance shaped; the flower heads, typically numbering 5 to 60 (but 160+ on a few species) appear on a spike, each flowerhead containing a number of small tubular 5-lobed pink-purple florets. Local variations in species populations will be observed. Rootstocks are corms and rhizomes.
L. aspera can grow from 16 to 48 inches high on an unbranched stiff ridged stem, covered with short stiff hair within the floral array. The stem while green, will usually have some purplish tints.
The leaves along the upper part of the stem are numerous but not dense below the floral array. The lower stem leaves are longer with a gentle taper to a stalk and are sometimes gland dotted. The more basal leaves are + or - 7 inches long and 3/8 inch wide while the upper leaves are + or - 3 inches long and 3/16 inches wide. In the western part of the plants range, the leaves will have fine hair, otherwise not. Leaves are widest above the mid-point.
The floral array is a tall spike of loosely arrayed flower heads.
Flower heads, numbering from 10 or more, are all the same size, about 1 inch wide, they are not densely positioned on the spike, and each head contains 14 to 35 florets densely crowded into a button shaped head. Each head has a short ascending stalk (up to 1 inch long) containing a leafy bract. Buds open from the top of spike and move downward. Each floret has a tubular pink-purple corolla, finely hairy inside, whose 5 lobes spread outward at the throat. A long divided style is exserted from the tube but the 5 stamens, which tightly surround the style, are not exserted. The phyllaries (bracts) around the outside of the flowerhead are in a series of 4 or 5 with the outer series reflexed. The middle series have wide irregularly cut edges and rounded tips. Part of the edges are whitish-translucent. The outer ones are green or green with purple tips while the inners become purplish.
Seed: Fertile flowers produce a dry seed (a cypsela), obconic shaped, with 8 to 11 ribs and bristly hair attached for wind dispersion. Seeds need at least 60 days of cold stratification for germination.
Habitat: This species of Liatris prefers full sun in well drained soil with dry to moderate moisture conditions. Long-tongued bees and butterflies will visit these plants. It grows from a corm-like structure with fibrous roots. Unfortunately, rabbits and deer like the plant too. It will bloom in August if an early spring, otherwise early September.
Names: The genus Liatris is an old name whose meaning has been lost. The species aspera, means 'rough', referring perhaps to the stiff short stem hair. The author name for the plant classification, ‘Michx.’ is for Andre Michaux (1746-1802), French botanist who made many exploring expeditions in the U.S. collecting and cataloging many species. Two important works of his are the Histoire des chênes de l'Amérique septentrionale (1801 - Oaks of North America), and the Flora Boreali-Americana (2 vols., 1803, published posthumously, containing the description of this species). His son Francois, traveled with him and the father’s notes were later used for the 3-volume North American Sylva, for which Thomas Nuttall provided some supplements.
Comparisons: The button shaped heads of the floral array separate this species from the other Blazing Stars except for the Northern Blazing Star, L. scariosa. Both species have similar shape heads and both can have stem hair. L. aspera however, has up to 35 florets in the flower head whereas L. scariosa has that as a minimum; also the middle phyllaries of L. aspera have irregularly cut tips whereas on L. scariosa they are broadly rounded.
Above: The floral array - Flower heads open from the top of the spike downward.
Below: 1st and 2nd photos - flower heads of L. aspera showing the floret details. 3rd photo - a stem showing the spacing of flower heads. You will generally find this species blooming in August to early September.
Below: 1st photo - Flower buds developing - note the head stalks and the stem hair. 2nd photo - The corm-like storage organ and fibrous roots.
Below: 1st photo - A single flower head showing the middle phyllaries of the heads with wide irregularly cut edges and rounded tips. 2nd photo - Middle stem leaves are numerous but not densely packed on the stem.
Below: 1st photo - Seeds are an obconic (narrow inverted pyramid) cypsela with ridges and fine surface hair. 2nd photo - A mid stem leaf. These are longer and have an gentle taper to a stalk.
Below: The basal leaves (top) are + or - 7 inches long and 3/8 inch wide while the upper leaves (bottom) are + or - 3 inches long and 3/16 inches wide.
Notes: None of the Liatris are indigenous to the Garden area. All were brought in by the curators. L. aspera was not listed on Martha Crone's 1951 Garden census but was present by the time of 1986 census. This species is native to Minnesota, occurring in most counties except the NE quadrant. In North America it is found in the U.S. from the central plains eastward to the coast, but absent in the NE from Rhode Island north into New England. In Canada it is known only in Ontario.
In Minnesota five species of Liatris are considered native and several others have been reported but have never been collected. The native five are L. aspera, Rough Blazing Star; L. cylindracea, Ontario Blazing Star; L. ligulistylis, Large-headed (or Rocky Mountain) Blazing Star; L. punctata, Dotted Blazing Star; L. pycnostachya, Prairie Blazing Star.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"