Lysimachia barystachys aka Manchurian Yellow Loosestrife

Lysimachia barystachys is a perennial in the primrose family, Primulaceae. Its common name is Manchurian yellow loosestrife, though its flowers are white. It comes from eastern Asia, including China, Japan, Korea, and Siberia. Wild plants grow on sunny hills and grassy mountain slopes. They also grow in mountain meadows and among shrubs. It is not native to Britain or Ireland.

In gardens, it forms clumps with strong growth. Plants reach about 1.6–3.3 feet [0.5–1 metre] tall. Their spread is about 0.3–1.6 feet [0.1–0.5 metres]. They take two to five years to reach full size. The stems bear hairs, and the leaves have fine hairs along their edges. Leaf shapes range from oblong to lance-shaped. The plant sheds its leaves rather than keeping them through winter. Small white flowers form long, dense spikes in mid to late summer. The ends of these spikes often curve.

Give this plant humus-rich soil that stays moist through summer. Full sun suits it best, but it also tolerates partial shade. It grows in clay, loam, sand, and chalk soils. Acid, neutral, and alkaline soils all suit it. The RHS lists both moist, well-drained ground and ground with poor drainage. Plants can grow in exposed or sheltered sites. The RHS gives it a hardiness rating of H6. Plants For A Future lists USDA zones 4–8.

This species suits flower beds, borders, and informal cottage gardens. The RHS also suggests prairie plantings and wildflower meadows. Its white flower spikes bring summer interest to these settings. Rhizomes let the clump spread, sometimes fast when conditions suit it. Divide plants at intervals to keep that spread in check. Gardeners can raise new plants from seed or divide existing clumps. Cut stems back once flowering has ended. Slugs and snails may attack it, though diseases are seldom a problem.

Plants For A Future records cooked young leaves and stems as edible. It gives the plant a low food-use score of one out of five. The same source reports no known hazards. That statement does not establish safety for every person or pet. It records no known medicinal uses or other uses beyond those described. Its main garden role remains a flowering perennial for moist ground.