Caragana arborescens aka Siberian Peashrub

Caragana arborescens is a shrub in the pea family, Fabaceae. Gardeners also call it Siberian peashrub or Siberian pea tree. Its native range spans Central Asia, Siberia, and Korea. It also grows wild in Mongolia and northern China. This deciduous plant forms several stems and sheds its leaves. It can grow as a small tree when trained.

Garden plants reach 15–20 feet [4.6–6.1 metres] in height. Their spread reaches 12–15 feet [3.7–4.6 metres]. Some plants stay below 10 feet [3 metres]. RHS gives a wider height range, reaching 26 feet [8 metres]. Upright branches form a rounded or oval crown. The base often lacks leaves and branches. Young stems look glossy and green, with grooves along them. Older bark turns gray-brown and has clear lenticels. Small paired spines can form where leaves join stems.

The green leaves are pinnate, with eight to twelve leaflets. They lack a single leaflet at the tip. Young leaves have fine hairs, then become bright green. Fall brings a dull yellow-green shade rather than strong color. Yellow flowers resemble pea flowers and open mainly in May. They grow alone or in small groups on older wood. Slender pods follow, turning from green to brown in summer. Ripe pods split with force and release their seeds. The split shells can remain on branches for some time.

Grow this shrub in full sun and well-drained soil. It also tolerates light shade, according to Oregon State. It accepts clay, loam, sand, and chalk soils. Acid, neutral, and alkaline soils all suit it. Poor soil, drought, salt, and strong winds rarely limit growth. Its roots fix nitrogen. It needs little upkeep and suits difficult garden sites. Sources rate it for USDA zones 2–7 and UK H7. Use it for hedges, screens, windbreaks, or shrub borders. Its dense growth also offers cover for wildlife. Flowers add spring color, though sources give its overall display modest ratings.

Serious pest and disease trouble is not usual. UConn lists leafhoppers and canker among possible problems. RHS notes possible honey fungus damage where that fungus occurs. The degree of risk remains unclear. Oregon State reports noxious weed listings in some Midwestern states. This limits its suitability where local rules restrict planting. Seed and softwood cuttings offer ways to raise new plants.