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. pycnostachya grows from 2 to 5+ feet high on erect leafy stems on which the amount of stem hair varies by the variety, of which there are two - explained below.
Leaves: There are both basal and stem leaves. Basal leaves are linear to narrowly lance shaped up to 1/2 inch wide and + or - 24 inches long. These appear in Spring long before the flowering stem appears. Stem leaves gradually but then abruptly change to linear, narrow, densely populating the stem in alternate manner and becoming bract-like near the top. Mid stem leaves can be + or - 6 inches long and upper leaves 1-1/2 inches long and 1/16 inch wide. Leaves are not hairy or glandular.
The floral array (flower area) appears as a dense spike. The spike contains a large number of densely packed flower heads without stalks. (I have counted over 160 heads on some stems.) Flower heads open from the top of the stem downward.
Flowers: Each flowerhead holds 5 to 8 florets which have pinkish purple 5-lobed tubular corollas without hair on the inside. The stamens number 5 and are united around the style part way up the corolla tube and are slightly exserted but the style is longer, deeply bifurcated and more exserted. The phyllaries around the outside of the flower head are in 4 to 5 series, generally oblong-lanceolate, unequal in size, mostly without hair, but with margins that are slightly translucent and sometimes with fine hair. Tips are pointed and curve outward to fully re-curving. Outer ones generally remain greenish, inner ones may pick up some purplish color on the tips.
Seed: The fertile flowers produce a dry seed (a cypsela), oblong, 3.8 to 4.5 mm long, ribbed, with a tawny color pappus attached for wind dispersion. Seeds require 60 days of cold stratification for germination.
Varieties: The two varieties of L. pycnostachya are var. pycnostachya, which is considered the species native to Minnesota, and var. lasiophylla. The former has stems that tend to be without hair or only sparsely hairy in the floral array with leaves that are without hair. The latter variety has stems that are moderately to densely hairy and the leaves also usually have hair.
Habitat: Prairie Blazing Star grows from a globose corm structure, which can produce additional plants. For good plant growth, sun and adequate moisture are required. Dry conditions will cause leaf loss and too little sun will cause twisted growth. Planting depth - the top of the corm should be 1 inch under the surface. This blazing star blooms as early as mid-July.
Names: The genus Liatris is an old name whose meaning has been lost. The species pycnostachya, is from two Greek words - pyknos, meaning 'dense' and stachys, meaning 'ear of corn' or a spike, all referring the the dense cluster of flower heads on the stem. As you can see above, a number of common names have been attached to this plant. The Garden uses the same name as USDA and the University of MN - Prairie Blazing Star - whereas Flora of North America calls it Prairie (or Cattail) Gayfeather. The MN DNR refers to it as Great Blazing Star. This is why scientific names are important.
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 were the Histoire des chênes de l'Amérique septentrionale (1801 - Oaks of North America), and the Flora Boreali-Americana (2 vols., 1803, published posthumously, and this species classification was published in this volume). His son Francois, traveled with him and the father’s notes were later used for the 3-volume North American Sylva. In earlier times this species was called Lacinaria pycnostachya.
Comparisons: Liatris pycnostachya is similar to L. spicata, except that L. spicata has more flowers per head and has rounded phyllary tips which do not curve outward. L. spicata and L. pycnostachya are difficult to distinguish without close inspection. One variety of L. spicata, var. spicata, has green phyllaries whereas a second variety, var. resinosa, has purplish phyllaries.
Above: The floral array. Drawing courtesy USDA-NRCS PLANTS Database / USDA NRCS. Wetland flora: Field office illustrated guide to plant species.
Below: Flower heads have 5 to 7 individual florets in each head. The styles are greatly exserted from the corollas which have wide spreading lip lobes. 3rd photo - The leafy and the sparsely hairy ridged stem.
Below: The difference between basal leaves - top, 24 inches by 1/2 inches and mid stem leaves - bottom - 6 inches by 1/18 inch. Upper leaves are even shorter and narrower.
Below: 1st photo - Note the outward curving pointed tips of the phyllaries. 2nd photo - Flower heads forming seeds. Note the stalkless heads.
Below: The fertile flowers produce seed heads containing oblong 3.8 to 4.5 mm long, ribbed cypselae with a tawny color pappus attached for wind dispersion.
Below: The root system of Prairie Blazing Star showing several corms and the fibrous roots descending from them.
Below: Long before the flowering stem rises, the plant puts out in Spring a dense clump of basal leaves.
Notes: Eloise Butler first recorded planting this species in 1907 from her source at what is now Minnehaha Park in Minneapolis. She noted planting it on 5 occasions in 1914 and in April 1917 she obtained 12 plants from Horsford's Nursery in Charlotte Vermont; and 5 plants from Mahtomedi MN and 4 from Fort Snelling in 1918 and more from there in 1920. Additional plantings in 1922, '24, '25, and '26 . Curiously, Martha Crone did not list the species in her 1951 Garden Census although she reported planting it on July 31, 1938, planting seeds in '44 and plants in '45, '46, '47, and '48. She planted more in 1954 and '55. The plant is native to the central United States and in Minnesota is found in most counties south and west of a diagonal line running from Polk and Clearwater counties down through the north metro area counties. The plants range in North America is restricted to the Central plains states from the Canadian border south to gulf and eastward to New York and Pennsylvania. Absent in the SE states and in most of New England.
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"