Hoary alyssum

June 11, 2015

Berteroa incana (L.) DC. Brassicaceae (Mustard family)

Life cycle

Annual, biennial or short-lived perennial.

hoary alyssum flowering plant
Hoary alyssum flowering plant.


Seedling leaves initially develop from a basal rosette. Basal leaves are hairy, oblong and up to 3 inches long with smooth to slightly wavy margins and long stalks. Stem leaves are similar but smaller and alternate and gradually become stalkless. Leaves are covered with gray, star-shaped hairs that result in a grayish green appearance.

hoary alyssum seedling
Hoary alyssum seedling.


Erect, stiff, up to 4-foot-tall stems bolt from a basal rosette to flower. Up to 10 stems may form per taproot with many branches near the top. Stems are covered with gray, star-shaped hairs that result in a grayish green appearance.

Flowers and fruit

Numerous white flowers with four petals so deeply divided that they resemble eight petals are found in elongated clusters. Fruit are hairy, oval and slightly flattened, grayish green seed pods with a short beak on the end. Seed pods are usually held close to the stems and yield oblong, rough and narrowly winged, grayish to reddish brown seeds.

hoary alyssum flowers hoary alyssum seed pods
Hoary alyssum flowers (left) and seed pods (right).


Seeds and root crowns.

star-shaped hairs
Gray, star-shaped hairs.


Plant parts can be toxic to horses.

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