Japanese spurge arrived from Japan and northern China and never looked back. In zones 4 to 9 it forms dense, weed-suppressing colonies of glossy evergreen foliage 6 to 12 inches tall, spreading by rhizomes across the dry shade under large trees where most plants give up. Small white flower spikes appear in early spring, modest but welcome. The plant reaches full coverage in roughly three years when new plugs are spaced 6 to 12 inches apart.

Full sun bleaches the foliage to an unpleasant yellow-green, so site it in part to deep shade. It tolerates drought once established but prefers moist, slightly acidic soil with good organic content. Leaf blight can be a problem in humid, still conditions — thin the planting if air circulation is poor and avoid overhead watering. On slopes and banks it holds soil reliably, and as a foundation planting it stays tidy without much intervention.