Photo by Ira Tucker.
Botanical name: Hylotelephium (Sedum) spectabile
Common name: Showy stonecrop
Family name: Crassulaceae (Stonecrop family)
Native range: Eurasia
Location in Duke Gardens: Historic Gardens, Doris Duke Center Gardens
USDA Hardiness Zones: 3-10
The Mary Duke Biddle Rose Garden is awash with pink in late September and early October—not so much from the roses (though there are a few still blooming), but from dozens of showy stonecrop plants (Hylotelephium spectabile) scattered at regular intervals in the round raised beds surrounding the Roney Fountain. With their succulent, fleshy leaves and dense, flat clusters of tiny, star-shaped pink flowers, showy stonecrop more than lives up to its name, contrasting beautifully with the spiky blue agaves (Agave sp.), evergreen beaked yuccas (Yucca rostrata), and perennial bunchgrasses in curator Mike Owen’s design. You will no doubt see large quantities of bees and other insects surrounding them, attracted to the flowers as a late-season nectar source.
A close relative of ornamental jade plants (Crassula ovata) commonly kept as houseplants, showy stonecrop and other members of its family have developed their own special version of photosynthesis, known as Crassulacean acid metabolism (CAM). Unlike regular photosynthesis, plants utilizing CAM keep their stomata, or pores in their leaves, closed during the day, releasing carbon dioxide only at night. This significantly reduces water loss during photosynthesis, thus increasing its efficiency. It’s no coincidence that the vast majority of the plants utilizing CAM are found in dry or desert conditions. Although CAM is used by a wide variety of otherwise unrelated plants, including cacti, it was first discovered in the Crassulaceae—hence the name.
Showy stonecrop was formerly placed in the genus Sedum, and is still listed under that name in many garden publications. The primary difference between the Hylotelephium and Sedum genera is that plants in Hylotelephium grow upright with long flowering stalks, while those in Sedum sensu strictu tend to sprawl or stay lower to the ground.
Regardless of what you call them, showy stonecrops are tough, durable and survive for long periods without water or care, making them an excellent choice for xeric or lower-maintenance gardens. They are also capable of regenerating from a single leaf. Many cultivars of showy stonecrop are available for sale, including some hybrids with the related Eurasian orpine or live-forever (H. telephium). Perhaps the best-known is ‘Herbstfreude,’ sold under its English trade name AUTUMN JOY, as well as the compact dwarf ‘Mini Joy’ and bright magenta ‘Neon,’ all of which you will find growing throughout the Historic Gardens and the Doris Duke Center Gardens.