Invasive Species Council of British Columbia
Invasive Plant

Hoary alyssum

Berteroa incana
Warning icon


Toxic to horses. Be cautious of Hoary alyssum if you have horses on your property, or you have hay crops. Once this plant gets into the hay, it can cause serious harm to the horses that consume it.

About This Species

Hoary alyssum (False hoary madwort, Hoary berteroa) prefers dry, disturbed sites such as roadsides, rail embankments, and rangelands. It is native to Europe. Hoary alyssum spreads quickly through a long season of seed production. Seeds are dispersed by vehicles, equipment, footwear, wildlife, and birds. It can also contaminate hay. Hoary alyssum is designated as a Regional Noxious Weed by the BC Weed Control Act, as well as a Regional Containment/Control species by the BC Provincial Priority Invasive Species List. 

How to Identify

Hoary alyssum is upright to 0.7 m tall and is covered in star-shaped hairs. 

It has small white flowers with deeply notched petals. Oval seedpods are 5-8 mm long, somewhat flattened, and held close to the stem. 

Leaves are greenish grey in color and clasp closely to the stem. 

Take Action

Prevention is the best approach.

Play Clean Go


Learn about best practices


Use the app

Observe and report to protect BC’s biodiversity

Report through this website

Use our form to tell us what you’re seeing and where.



Click or drag files to this area to upload. You can upload up to 3 files.
Please include photos of the suspected species to help potential identification by experts.
Please be specific and give us an address if possible.