Zone: 3 to 8
Soil: sand to loam
Light: Full sun to part sun
Bloom colour: lilac, mauve, purple, white
Bloom period: August
Height: 1.5 to 5 feet
Moisture:Varies (see note below)
Attracts: Especially attractive to monarchs
Notes:This plant produces flowerheads that start blooming at the top of the flowerhead for several weeks. They are highly regarded as cut flowers and are known for attracting a variety of bees and butterflies. I find their popularity with insects to be overrated in Ontario, but if you want to attract Monarch butterflies, then you absolutely have to plant Liatris ligustylis. This species does not do well in drought conditions. If your soil dries out, consider planting Liatris aspera instead as it has similar button shaped flowers that ascend up the main stem.
The most common species sold in nurseries is Liatris spicata (Marsh Blazing Star). As the name suggests, this species prefers ample water and fertile soils but can survive surprisingly well in dry sandy soil with little bit of watering. This species is the most popular liatris on the shelves because its stem is crowded with flowerheads.
Liatris cylindracea is the smallest and least attractive of the species mentioned here. The individual flowerheads are stunning but they are sparsely distributed up the stem. This Liatris may be your best choice though in dry sandy soils where other species cannot thrive. Plant it amongst groups of Monarda punctata as the flowers of this Liatris will peek through.
No Liatris should be planted in clay soil because there is a high chance of root rot killing the corms over the winter. For Liatris pycnostachya and Liatris spicata, you might be able to get away with a clay loam soil. Whatever soil you use, it must be well drained. If you have dry sandy soil, then try planting Liatris aspera, Liatris cylindracea, or Liatris punctata. Liatris punctata is a smaller species that survives drought with really deep roots. It is not native to the province of Ontario, but it is available in some nurseries.
The members of this genus do not have particularly attractive leaves. Therefore, excepting Liatris punctata and Liatris cylindracea due their smaller size, these plants are best planted either between plants or behind plants. All the species mentioned are native to Canada, except for Liatris pycnostachya. The species native to Ontario are L. aspera, L. cylindracea and L. spicata.