The biology of invasive alien plants in Canada. 6. Berteroa incana (L.) DC

Abstract

The cruciferous weed Berteroa incana, hoary alyssum, has been known in temperate North America since the late 19th century, but has recently begun to spread aggressively in upland and dry areas in the Great Lakes and western foothills regions of both Canada and the United States. It is an annual, winter annual to short-lived perennial and is considered an invasive weed in turf, rangelands, pastures and forage crops, with harmful effects on horses an added concern. The species is most common on sandy gravel and poorer soils. It has recently invaded Christmas tree plantations in Michigan. Its prolific seed production, woody stems and deep taproot enable it to persist under dry conditions and to resist mechanical control; and it has virtually no natural enemies in North America. It can be partially controlled by herbicides in crops it has invaded, but herbicides are not generally used on rangelands, pastures, turf and natural and semi-natural areas, where it is now prevalent.