Weed Department
Idaho State Noxious 
Weed Law
Hoary Cress


General Description: It is a rhizomatous perennial that generally grows up to around 2 feet tall, sometimes 3 feet tall. Plants generally covered in short hairs but can be hairless.

Flower Description: Plants have many somewhat flat-topped clusters of white flowers. Each flower has 4 petals and blooms April to July.

Leaf Description: Leaves are alternately arranged on the stem, blue-green and lance shaped. Lower leaves have stalks while upper leaves are without stalks and have two lobes clasping the stem. Leaf margins are irregularly toothed to smooth (entire).

Stem Description: Stems are upright to somewhat trailing on the ground. Stems with a lot of branching near the top.

Fruit/Seed Description: Seed pods (silicles) are inflated and generally rounded to somewhat heart-shaped (especially at the base) and hairless. Seeds are dark brown and 0.08 inches (2 mm) long. One mature plant can produce 1,200 to 4,800 seeds.


Interesting Facts:

Hoary cress is a highly competitive plant forming a monoculture, and once established, it easily displaces native vegetation. It has the potential to reduce the value of high-price wheat lands.