Pachysandra [pack-ah-SAND-dra], also called Japanese spurge, has enjoyed wide popularity as a versatile, shade-loving groundcover since it was introduced from Japan in the 1880s. Its attractive, evergreen foliage forms a low, even carpet under the shade of trees, on steep banks, or on the north side of the house where many other plants refuse to grow. As living mulch under trees and shrubs it helps protect them and the soil they grow in. Pachysandra is easy to grow, spreads in fairly quickly and maintains its dark green leaf color all year round.
Pachysandra (Pachysandra sp) is very reliable over a large portion of the US. It can withstand winter cold as far north as northern New York State and into New England, around the Great Lakes and into South Dakota (Zone 4). It does fine in the South down through Georgia (Zone 8), but cannot handle the climate in Florida.
Size: Japanese pachysandra grows 6 to 10 inches tall; maybe a bit taller in dense shade. Plants spread rapidly by an underground network of stems and fibrous roots to create solid swards of lush foliage of uniform height within a year or two. They willingly spread as far as you allow.
Foliage: The bluntly toothed, 4-inch-long leaves grow alternately along each stem, clustering in a whorl at stem tips. New leaves are a pretty light green, which gradually changes to a rich dark green. In much of their range they retain their color all year round. A variegated type of Japanese pachysandra has gray-green leaves edged with creamy white. Another has particularly lustrous leaves.
Flowers & Fruit: Small white flowers appear on 1 to 2 inch long spikes that emerge from each whorl of leaves in early spring. While they are inconspicuous compared to other spring flowers, pachysandra blooms do add a handsome contrast to the dark foliage and are quite attractive in large plantings. They are favorites of honeybees.
Better Varieties: Japanese Pachysandra (Pachysandra terminalis) ‘Green Carpet’ has a more compact growth habit and grows closer to the ground than the species with deeper green foliage.
‘Variegata’ or ‘Silver Edge’ has green and white mottled leaves. A slow grower, it does best in light shade.
‘Green Sheen’ is a new variety with truly shiny leaves. Takes dense shade; grows 10 to 12 inches tall.
Allegheny spurge (Pachysandra procumbens) is native to the US. It bears whorls of leaves that are wider than those of Japanese pachysandra. They are duller deep green with a purplish tinge. The leaf tissues are puckered along pale veins, giving the foliage a quilted look. The flowers are white to pink or purple, and appear before the foliage unfolds. The leaves develop an interesting silvery-gray mottling in the fall. Established Allegheny spurge sometimes bears small, whitish berries in the fall.
Allegheny spurge does not spread as aggressively as its Japanese relative, and tends to form clumps, which recommends it for some landscape situations. A slow growing plant that prefers moist sites, it is not widely grown but is a desirable plant. It grows in the southeastern states (Zones 6 to 10) and is evergreen there over the winter, but dies to the ground further north.