Sedum, also known as stonecrop, is a popular and diverse group of succulent perennial plants favored for their drought tolerance. Yes, Sedum does spread, but the rate and manner of expansion depend entirely on the specific variety. Low-growing types are aggressive groundcovers that quickly colonize an area. Upright types are clump-forming plants that only increase their diameter slowly over time. Understanding these two main growth habits is the starting point for managing its presence in any garden setting.
How Sedum Expands its Territory
The primary and most effective means of proliferation for many low-growing varieties is vegetative spreading, a form of asexual reproduction. This occurs when a stem segment or fleshy leaf contacts the soil and develops roots, forming a new, genetically identical plant. This ability to root along the stem allows creeping Sedum to form dense, spreading mats across the ground. Many species also reproduce via offsets (small plantlets) that form directly at the base of the mature plant, gradually increasing the size of the original clump; if the cluster grows too large, the main crown may eventually die out in the center, requiring periodic division. Self-seeding is another reproductive method, though it tends to be less predictable and slower.
Comparing Groundcover and Upright Sedum Spreading
Groundcover Varieties
The Sedum genus is broadly divided into two categories, and their spreading habits greatly impact landscape planning. Groundcover Sedums, such as Sedum acre or Sedum spurium ‘Dragon’s Blood,’ are the true spreaders. These low-growing varieties form dense, weed-suppressing mats by sending out stems that root readily wherever they touch the ground. They are often used for erosion control or filling large, dry areas because of their rapid coverage. A single plant can quickly sprawl two to three feet wide, often increasing its diameter by several inches per month once established.
Upright Varieties
In contrast, Upright Sedums (often reclassified into Hylotelephium, like ‘Autumn Joy’) do not spread aggressively. These plants are defined as clump-formers, growing as a single, substantial mound. While the clump increases in diameter each year, this expansion is slow and steady rather than creeping. Upright varieties typically reach a mature size of 1 to 2 feet tall and wide before requiring division to maintain health. Their growth is focused vertically, making them suitable for mixed borders where a controlled, structural plant is desired.
Controlling and Promoting Sedum Growth
Gardeners can actively manage Sedum’s spread depending on their desired outcome, whether it is to contain an aggressive groundcover or encourage faster coverage. To control the spread of creeping varieties, simple physical barriers and regular pruning are effective measures. Installing a shallow, rigid edging or border can prevent runners from rooting into unwanted areas. Containment involves trimming back any stems that extend beyond the desired boundary before they root into the soil.
For upright, clump-forming Sedums, the primary management technique is periodic division. Every few years, digging up the entire clump and cutting it into smaller sections maintains the plant’s vigor and health.
If the goal is to promote faster coverage, gardeners can utilize the plant’s natural tendency toward vegetative propagation. Taking small stem cuttings and laying them directly on the soil surface encourages rooting. Ensuring the soil is well-drained and the area receives ample sunlight maximizes the establishment and growth rate.