As its common name of “Siberian peashrub” implies, the Caragana arborescens shrub is native to an area of Asia encompassing Siberia, Kazakhstan, Mongolia and China. It is now distributed throughout Europe and North America. Despite its exotic status and rating as an invasive species in some areas, the caragana shrub is not generally regarded as a noxious invader in most of North America. Caragana, a deciduous perennial, is cultivated throughout Canada and in the western and upper midwestern regions of the United States as an ornamental shrub or small tree. Its Siberian heritage means the shrub can tolerate some very cold conditions, as low as -40 degrees Fahrenheit. Caragana is also rated as an exceptionally drought-tolerant shrub, suitable for xeriscape plantings in sandy soils for hardiness zones 2 through 7.
When planting caragana shrubs from seed, soak the seeds in warm water for about one day, then place them in the ground in early spring while the weather is still cool to cold. Caragana prefers full sun exposure and can attain heights of 12 feet, so plan your planting location accordingly. It's a good choice for hedges and windbreaks, and can make a dramatic and visually arresting property line marker, with its lush leafy growth in spring and profusion of small yellow flowers in early to midsummer. The caragana can tolerate partial shade, but its foliage can be affected by leaf spot, red spider mites, blister beetles, grasshoppers and aphids.
The caragana shrub's adaptability to poor soil conditions, including alkalinity and salinity, its remarkable tolerance for both drought and cold, and the fact that it requires very little in the way of maintenance, make it an attractive option for landscapers in colder, drier regions. However, before adding the caragana to your landscaping plan, check with agricultural and horticultural experts in your local area to make sure the shrub is not listed as a noxious or invasive threat in your state.