Japanese spurge, or Japanese pachysandra, is a widely planted evergreen in American shade gardens, forming a low, glossy mat under trees where grass won't grow. It spreads by underground stems into nearby woods and is now considered invasive in parts of the eastern US.
Appearance
- Growth form
- A low, evergreen, partly woody plant about 6–12 in (15–30 cm) tall. Creeping stems knit into a dense mat several feet across.
- Leaves
- Shiny, dark green, diamond-shaped leaves, about 1–2¼ in (2.5–6 cm) long, crowded in whorl-like clusters at the stem tips. Only the upper half of each leaf is coarsely toothed.
- Flowers
- Short spikes of small white flowers sit at the tips of the stems. There are no petals; male flowers fill the upper part of each spike and female flowers sit at the base.
- Flowering time
- Early spring, typically late March through April.
Look-alikes
Allegheny spurge has larger, mottled, blue-green leaves that turn bronze-brown in fall and winter, and its pinkish flower spikes rise from near the base of the stems instead of from the stem tips. It grows in clumps rather than a continuous mat and is less prone to Volutella blight.
Why they get mixed upIt is the native American relative and is sold as a replacement for Japanese pachysandra.
Where it lives
- Typical habitats
- shade gardens
- under trees
- forest understory (escaped)
- Range
- Native to Japan and China; some references also list Korea. Widely planted in the eastern US and Canada, where it has escaped into woodlands in some areas.
- Preferred conditions
- Partial to full shade in moist but well-drained soil. Hardy in USDA zones 5–8.
- Flowering
Flowers Mar–Apr
Flowers Mar–Apr
Growing it
- Care
- Its main disease is Volutella blight, which causes leaf and stem dieback. Euonymus scale is a common pest.
- Propagation
- Spreads mainly by underground stems () and rarely seeds itself. Gardeners divide clumps or root stem cuttings.
Name and classification
- Varieties and forms
- Garden forms include the compact, darker 'Green Carpet' and the white-edged 'Variegata'.
Conservation
- IUCN Red List
- NENot EvaluatedNot yet assessed
- Status
- Several eastern states list it as an invasive plant. Native groundcovers such as Allegheny spurge are suggested as alternatives.
- Threats
- Where it escapes, its dense mats spread from the original planting and can crowd out native plants.
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