Is Sedum Freeze-Hardy?

An upright species of herbaceous stonecrop growing in a pot.

Hardiness refers to a plant's ability to survive environmental conditions such as drought or winter cold. Stonecrops (Sedum spp.) comprise nearly 400 difference species, each with specific genetically-determined tolerance to freezing temperatures. Most stonecrops can survive subfreezing temperatures.

Types

Stonecrops encountered in gardens are either upright clumping perennials or low, creeping ground-cover types. Depending on the species, winter frosts and freezes can kill the above-ground stems on the upright types while the plant remains alive but dormant underground. Creeping stonecrops often remain partially evergreen after exposure to winter freezes.

Considerations

It's important to grow a stonecrop species that is tolerant of the temperatures in your climate. Many grow well across U.S. Department of Agriculture hardiness zones 3 through 9 where frosts and freezes sometimes occur. However, some tropical species, like Sedum frutsecens and the burro's tail, Sedum morganianum, must never encounter a freeze.

Insight

Insulating stonecrops over the cold winter months can improve a plant's survivability. Once the fall frosts occur and growth stops, don't cut off dead leaves or stems until early spring. This dry tissue helps insulate the stem crown and roots from cold air. In fact, some gardeners may place a light mulch over the plants to shield them from cold, especially if snow cover is lacking.

References

• "A-Z Encyclopedia of Garden Plants"; Christopher Brickell and H. Marc Cathey, eds.; 2004

Resources

• National Gardening Association: USDA Hardiness Zone Finder
• Learn2Grow: Sedum Species and Cultivars