Sedum, commonly known as Stonecrop, is a genus of popular garden plants characterized by their thick, fleshy, succulent-like leaves. These plants are appreciated for their drought tolerance and ability to thrive in poor soils, making them a low-maintenance favorite. The majority of garden-variety Stonecrops are reliably hardy perennials, meaning they return year after year with fresh growth in the spring.
The Perennial Nature of Sedum
Sedum’s ability to return annually stems from its classification as an herbaceous perennial. This means its foliage and stems may die back, but the root system remains alive underground. Most common Sedum varieties are rated for USDA Hardiness Zones 3 through 9, demonstrating an impressive range of cold tolerance. As temperatures drop, the plant enters a state of dormancy, conserving energy in its roots and crown to protect against freezing conditions. This deep-seated root survival ensures the plant will reliably sprout new growth once the weather warms.
Key Differences in Sedum Types
The winter appearance of Sedum depends heavily on its growth habit, which generally falls into two distinct categories: upright and creeping types. Upright Sedums, such as the well-known ‘Autumn Joy’ (Hylotelephium varieties), grow tall and form distinct clumps. These types die back completely to the ground after a hard frost, leaving behind dried, stiff stems and seed heads that provide winter interest. New growth emerges entirely from the base of the plant once the dormancy period ends.
Creeping or groundcover Sedums, however, have a low, mat-forming habit and often behave differently in winter. Varieties like ‘Angelina’ frequently remain semi-evergreen or merely turn a muted color, such as burgundy, bronze, or reddish-orange, retaining foliage close to the soil. This low-growing foliage acts as its own insulation and protects the plant crown.
Ensuring Sedum Returns: Winter Care and Dormancy
Successful overwintering largely depends on managing the conditions surrounding the plant’s root system during its dormant phase. The most significant threat to Sedum in winter is not the cold temperature itself, but excessive moisture that leads to root rot. Sedum’s succulent nature means it stores water in its leaves, making excellent soil drainage paramount, especially where winter precipitation is heavy. Amending heavy clay soil with grit or perlite before planting helps prevent standing water from accumulating around the plant’s crown.
When it comes to pruning, gardeners should generally delay cutting back the spent foliage of upright varieties until early spring. The dried, hollow stems and flower heads offer a layer of insulation that protects the plant’s crown from harsh weather. Leaving the structure intact also helps to trap insulating snow, which provides a consistent temperature buffer for the roots. Once new growth begins to appear at the base of the plant in spring, the previous year’s dead stems can be safely cut back to ground level.