Which perennials are most likely to be heaved up out of the ground in winter?
Repeated freezing and thawing of the soil during the winter months can lift up or heave some perennials out of the soil. Heaving exposes the plant’s crown and roots to cold, dry air. Perennials that have been heaved up out of the ground may be seriously damaged or destroyed.
Perennials most susceptible to heaving are shallow-rooted plants and those planted in late summer or early fall. Perennials prone to heaving include garden mum (Chrysanthemum spp.), Shasta daisy (Leucanthemum spp.), painted daisy (Tanacetum spp.), and coral bells (Heuchera spp.). Perennials planted in late summer/early fall are susceptible to heaving because they don’t possess extensive root systems and are more easily pushed up out of the soil. Generally, most well established perennials (those in the ground for 1 or more years) are not prone to heaving.
Heaving of perennials can often be avoided by planting in spring and mulching. Spring planting is especially important for garden mums, Shasta daisies, and other perennials prone to heaving. Perennials planted in late summer/early fall should be mulched with several inches of straw or pine needles in late fall.