Japanese Spikenard

Japanese Spikenard (Aralia cordata)

Udo, Mountain Asparagus

Part shade to full shade, moderately moist to moist, rich humusy soil; pH 5.5–6.5; tolerates clay with organic amendment; requires consistent moisture through summer.

90–120 cm tall in leaf, dying back fully to ground each winter; blooms July–August with white compound umbels on arching stems; spreads slowly by rhizomes to form clumps.

Division of the thick rhizome in early spring before emergence is the standard propagation method.

Native region: Not native to Tennessee; ornamental introduction from Japan and China.

Despite its height, Aralia cordata functions as a groundcover in the sense of filling large shaded areas under mature canopy where smaller groundcovers fail — the bold, tropical-looking compound leaves suppress competing vegetation effectively. The cultivar 'Sun King' with chartreuse-gold foliage is particularly useful for brightening dark corners in Middle Tennessee shade gardens. Crowns emerge late in spring — well into May — so mark planting locations to avoid accidental damage. Young shoots were historically harvested and eaten in East Asia; the large leaves and arching flower panicles attract pollinators. No significant pest issues in Tennessee; slugs can damage new growth in wet springs.