Plant Profile: Liatris (Blazing Star)

A North American genus of ±35 herbaceous perennials, a handful of Liatris species are available to European designers, all from the Midwestern prairies. They are valued for their attractive foliage and emergent flower spikes, which offer rich late-season colour before the plants die back to overwintering corms. Liatris is fully hardy, generally disease-free, and appropriately sized corms flower reliably the year of planting—a significant benefit from the designer’s viewpoint.

Each corm produces a neat cushion of grass-like basal foliage in spring, before one or more stiff flowering stems elongate through the summer, before flowering from the top downwards.

Despite belonging to the Asteraceae, Liatris lack ray florets and are not typically aster-like in appearance. The plants’ distinctive appearance is actually due to the massed effect of the extremely long two-branched styles that emerge from the otherwise insignificant flowers—it is these that create the characteristic shaggy texture and striking colours (violet-mauve, magenta, pink, or white, according to the variety).

The varieties most commonly encountered are L. spicata and its two ‘Floristan’ cultivars (violet and white), which are originally from marshy habitats and thrive best in retentive soils. At 1m to 1.2m, they are generally self-supporting, though in fertile conditions, the stems can overextend and fall over. In such situations, the dwarf cultivar ‘Kobold’ (to 50cm) is a useful alternative. By contrast, the imposing L. pycnostachya (to 1.8m) always needs propping and is unsuited to most urban situations.

For urban specifications, the drier-growing species L. aspera and L. scariosa are worthy of consideration since they tolerate poor, stony soils and exhibit excellent drought tolerance.

In extensive plantings, establishment from seed is possible, though results have sometimes proved poor (L. aspera is a component of Jelitto’s ‘steppe prairie’ seed mix developed by James Hitchmough). Cultivars should be vegetatively propagated to ensure consistency, though ‘Kobold’ is also offered as a seed strain.

This article was first published in the January 2024 issue of FloraCulture International. The author is Martin Deasy, a UK-based horticulturist and landscape designer.

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