Sorbaria sorbifolia aka False Spiraea

Sorbaria sorbifolia is a deciduous shrub in the rose family. Gardeners know it as false spirea or Ural false spirea. It comes from temperate parts of northern and eastern Asia. Sources place it across Siberia, China, Korea, and Japan. It grows fast and sends up shoots from its roots. These suckers can form large colonies beyond the original plant.

Several upright stems make a broad, coarse mound. In gardens, it often reaches 5–8 feet [1.5–2.4 metres] tall and wide. Some plants reach 10 feet [3 metres]. RHS lists an upper size of about 13 feet [4 metres]. New growth has a purple tint before turning dark green. The alternate, pinnate leaves have 13–25 narrow leaflets. Each leaflet has sharp, double-toothed edges and no leaf stalk. Leaves reach about 0.7–1 foot [0.2–0.3 metres] long. Their shape recalls the leaves of mountain ash. Neither the bark nor autumn leaf colour offers much display.

Small white flowers grow in upright panicles at stem tips. These clusters reach about 0.3–0.8 feet [0.1–0.25 metres] long. They form on new growth and stand above the leaves. Several sources place the main bloom in June and July. Chicago gives a wider season from May through August. After flowering, follicles develop in clusters at the stem tips. These dry fruits split open when ripe.

Full sun gives the best flowering, though plants accept partial shade. They prefer moist, rich soil that drains well. RHS lists clay, loam, sand, and chalk as suitable soils. UConn reports tolerance of a range of soil pH levels. Sources give USDA zones 2–8 and the UK rating H5. Prune in late winter or early spring, before new growth starts. Cutting an old plant near ground level can renew it. Remove unwanted suckers to keep the shrub within bounds.

False spirea suits screens, borders, and banks needing erosion control. Give it room where its spreading habit serves a purpose. Loose soil allows stronger spread; heavy clay can limit it. Sources report no major pest or disease problems. PFAF records cooked leaves and young shoots as food uses. It also warns that leaves and flowers contain hydrogen cyanide. Excess intake can cause fatal breathing failure. This food record does not establish that eating the plant is safe.