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Wisconsin Plant of the Week

Liatris spicata (L.) Willd.

Asteraceae (Sunflower Family)

Common Name:

marsh blazingstar

08/07/2000

Marsh blazingstar is prairie plant of moist sandy and calcareous prairies that blooms from August to September. In Wisconsin itís found only in the southeastern counties where it reaches the northern and western edge of its range.  Itís rare mainly due to habitat loss and is listed as a Special Concern species.

The slender spikes can be nearly 1.5 m tall with dense rose-purple  flower heads covering the top 1 m.  Leaves are alternate, linear and crowded, up to 30 cm long at the base and becoming shorter up the smooth stem. Each flower head has 5 to 10 flowers and the heads are attached directly to the stem.

Like most prairie plants all Liatris are adapted to survive fire.  They store food reserves in a round enlargement of the stem, called a corm, that forms several inches below the ground surface. The plants slowly propagate vegetatively as the corms multiply, and new plants also grow from seed.  Plants flower only after 2 or 3 years.

From a distance blazingstars are often confused with purple loosestrife, since both species bloom at the same time and have a similar color and spike form.  Blazingstar spikes bloom from the top down, so the oldest flowers are at the top.  Purple loosestrife spikes bloom from the bottom up.

Liatris is a strictly North American genus of sandy soils.  Wisconsin has seven species of blazingstars, but only L. spicata and the very similar Gayfeather, L. pycnostachya, are found on moist sites. Gayfeather is more common, found across the state south of the Tension Zone and prefers wetter sites.

The different species of Liatris are distinguished by their phyllaries -- the small leaf-like bracts under the flower heads.  Phyllaries on L. spicata are reddish, smooth, rounded at the tips and lie flat against the flower head. The phyllaries of L. pycnostachya are narrowly pointed at the tip, curve outward and are hairy, like the stem. 

  • Origin of the name: Liatris, unknown; spicata, L. tufted
  • Range:  NY, s. to FL, w. to WI, LA
  • WI Range:  Southeast only
  • Common associates: Big bluestem, mountain mint, boneset
  • Wetland Indicator Status: FAC
  • Coefficient of Conservatism: C = 6 (S&W), C = 8 (MI)
  • A Special Concern species in WI
     
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