Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Nevada Noxious Weed Field Guide – Hoary cress, Extension, University of Nevada, Reno, Field Guide

Stem

0.5-2 ft. tall; branched near top; covered with short hairs

Leaves

Alternate, 1-4 in. long, blue-green, oblong to lance-shaped and covered with short hairs; edges (margins) are toothed to smooth
Lower leaves have short leaf stems (petioles); bases of upper leaves have lobes that clasp the stem

Flower

White with 4 petals; occur in clusters that give plant a flat-topped appearance; occur from spring to early-summer
Seed pods are oval to heart-shaped; each contain 2 seeds

Root

Deep, spreading root system

Photo of hoary cress infestation next to a lake

Other

Grows best in disturbed, alkaline soils; often found in pastures, fields, roadsides, rangelands, waste areas and along waterways; known to occur throughout Nevada
Perennial; reproduces through roots and seeds
Also known as whitetop; 3 species occur in Nevada: hoary cress (C. draba) is most common but lens-podded whitetop (C. chalapensis) and hairy whitetop (C. pubescens) also occur

Control

Dig or pull individual plants for small infestations; remaining roots can produce new plants; frequent tillage or mowing for several years can reduce plant density
Apply 2,4-D to actively growing plants prior to bud stage; chlorsulfuron or metsulfuron from bud to early bloom; imazapic from full bloom until necrosis

Learn more about the author(s)

Heidi Kratsch

Also of Interest:

Nevada Noxious Weed Field Guide – Hoary cress