Latin Name: Berteroa incana

Physical Description: Hoary alyssum is an upright herb that can grow up to 1m tall, single, or multiple stems with small whitish hairs that cover the stems and leaves. The leaves are lance-shaped, rough and fell like sandpaper, greenish in colour and clasp closely to the stem. It has small white flowers that grow in clusters with deeply notched petals. Oval seedpods are 5-8mm long, somewhat flattened, and held close to the stem. One plant can produce about 2,600 seeds..

Type: Biennial or short-lived perennial forb.

Habitat & Impacts: Hoary alyssum is found primarily on disturbed sites and prefers sandy or gravely well-drained sites. Hoary alyssum can be a serious problem for horse owners as the ingestion of sufficient quantities can cause a number of diseases in horses. This species can also become a serious problem on heavily used rangelands and may displace native vegetation, reducing forage production for wildlife and livestock.

Method of Spread: This species reproduces exclusively by seed which is produced in moderate amounts by each plant. Seeds are produced from the first flower in late spring right up until frost and are spread by wind and water.

Mechanical: Hand-pulling can effectively remove small infestations or cutting prior to seed set can control seed production.

Chemical: 2,4-D Amine, dicamba, and mecoprop are effective at controlling hoary alyssum. This species has been difficult to control chemically in other areas of the province, possibly due to the timing of treatments.

Biological: There is no biocontrol agent available for control of hoary alyssum.

CCCIPC Priority & Treatment Strategy: Priority 1 (new invader) in all areas except the central coast where it is classed as N/A (not ecologically suited to the area) Since hoary alyssum is still a relatively new invader in the area, elimination of all sites is the goal.

Local Level: Hand pulling small infestations.

Landscape Level: Combination of chemical control and hand pulling for larger infestations.