Pachysandra Terminalis: Planting and Caring for the Japanese Spurge and Its Cultivars

Pachysandra terminalis, more commonly called "pachysandra" or Japanese spurge, is probably the most planted groundcover in temperate North America. This short (9-12 inches tall), semi-evergreen plant, introduced to horticulture from Japan circa 1882, is an essential part of many urban landscapes. It is capable of forming dense and solid 6 to 12-inch high carpets of evergreen vegetation.

Benefits of Planting Pachysandra

Japanese pachysandra can:

• Grow and thrive in climates from USDA (United States Department of Agriculture) zones 4 through 9;
  
• Rapidly spread 18 inches in all directions by rhizomes (underground stems) and provide quick cover when planted at four plants per square foot in optimum conditions;
  
• Multiply quickly because roots grow easily along the rhizomes, and cuttings made in summer months root well;
  
• Tolerate part sun but is partial to shade;
  
• Supply a dash of green where winter landscapes are likely to be shades of gold and brown. 
• Hold thin soil on the slopes alongside steps.

Caring for Pachysandra

Pachysandra beds can not be planted and left to fend for themselves. Newly planted pachysandra beds need gentle watering, weeding, and organic mulch such as medium-fine wood chips. Once established, they continue to need care. Beds look their best when:

• Growing conditions duplicate pachysandra's native ecosystems - filtered shade with loose, well-drained acid soils and generous amounts of organic matter. Clay or sandy soils and full sun promote yellow, skimpy looking plants.
• Fertilized with a combination of slow-release fertilizer and high water-insoluble nitrogen (WIN). Work fertilizer under the leaves to bring it close to the soil and prevent possible leaf burn, spotting and runoff.
• Cleaned thoroughly in spring. Gentle raking or using a leaf-blower is essential for removing debris from beds. Litter on beds leads to stem cracks and these breaks promote bacterial and fungal infection.
• Beds are thinned periodically. They thrive in well groomed, thin plots wiht good air circulation.
  
• Problems like leaf and stem spots, root rot and leaf dieback are noticed early on and treated. Euonymus scale insects can also be a problem.
  

Alternate Pachysandra Cultivars

Pachysandra terminalis cultivars come about when certain layers of the leaf mutate or slip and slide over each other producing something unlike the parent plant. This beauty is being watched to see how it grows and has yet to see the inside of a commercial propagating greenhouse. They grow more slowly than their older relatives do, and a little searching might be necessary to find them.

Pachysandra terminalis 'Green Sheen' and 'Green Carpet' are leaders among available cultivars in both consistent appearance and growth. Both of these plants grow approximately 6 to 10 inches high. They differ in amount of gloss in leaf appearance. A word of warning - the two are often confused.

Green Sheen, a Carey Award winner for 2001, is suitably named because its foliage displays a shiny dark green, almost mirror-like, luster that looks as if the leaves have been dipped in wax. Dale Chapman of the University of Connecticut selected and introduced this cultivar to the gardening scene. See landscape pictures and close-ups of 'Green Sheen' at the Monrovia Wholesale Company plant information site.

Green Carpet, while not as glossy as Green Sheen, has very shiny, neat-appearing foliage and reportedly grows shorter in some situations than Green Sheen. These plants also seem to produce more flower clusters than other cultivars. Green Carpet also won an Award of Garden Merit (AGM) from the Royal Horticultural Society (RHS).

There are also some bicolor variants. 'Silveredge' pachysandra has thin silver-white margins along the leaf edges, while 'Variegata' supposedly displays irregularly white variegated leaves. It is usually difficult to tell the two cultivars apart, if indeed they are two separate groups. Many plant lists refer to this cultivar as Pachysandra terminalis 'Silver Edge' ('Variegata'). These plants bring a bit of brightness to shaded garden corners. Applying water-retaining organic mulch like medium-fine wood chips improves growth.