Siberian pea shrubs are hard to beat for hardiness. These tough plants have been known to withstand temperatures as low as -40F. Bearing attractively divided light green foliage and yellow, pea-shaped flowers, the shrubs are attractive as they are tough. In addition, they make for fine screening plants as the shrubs bear many thorns.
- Common name: Siberian pea shrub
- Botanical name: Caragana arborescens
- Zones: 2 to 8
- Size: To 20 feet tall and 15 feet wide
- From: Areas of Asia
- Family: Fabaceae (pea family)
- Sun: Full sun or partial shade.
- Soil: Moist, but well-drained is best, but they will tolerate poor soils.
- Moisture: Siberian pea shrubs are drought tolerant.
- Mulch: A layer of mulch around the base of the plant helps conserve moisture and reduce competition from weeds. Leave a 4-inch gap between the mulch and shrub's stems.
- Pruning: To conserve blooms, prune in spring once the plants finish blooming. If you don't care about the flowers, prune anytime.
- Fertilizer: These shrubs don't usually require extra fertilizer. If you do fertilize them, it's best to use a balanced product, such as a 10-10-10.
- Seed: Harvest the seed as soon as it's mature, soak it in warm water for 24 hours, and sow in a cold frame or sheltered spot in the garden. Siberian pea shrubs may self-seed-if so, simply transplant self-sown seedlings.
- Cuttings: Take cuttings in summer.
- Aphids: These small insects often appear in large numbers on new growth. Spray them off daily with a stream of water; they will not attack a plant after being knocked off. Use an insecticidal soap or neem-oil-based spray if infestations are severe.
- Spider mites: Spider mites are tiny, nearly microscopic creatures that suck juices from plant cells. Spider mite damage often appears as a "stippling" effect on leaf surfaces. On the bottom sides of the leaves, there are often tiny webs. To deter spider mites, wash the plants frequently with water or use a systemic insecticide.
- Siberian pea shrubs are armed with thorns; avoid planting them near walks, drives, or other places the thorns could pose a hazard.
- Standard forms, grafted onto a rootstock, are often available, especially for weeping varieties.
- Caragana arborescens ‘Lorbergii': A cultivar with narrower leaflets than the species.
- Caragana arborescens ‘Nana': A dwarf selection to 5 feet tall and wide.
- Caragana arborescens ‘Pendula': This striking selection bears weeping branches; it's often grafted onto a rootstock and sold as a standard.
- Caragana arborescens ‘Walker': A cultivar with more finely divided leaves than the species and weeping habit.