Hoary Cress (Whitetop)
Brassicaceae (Mustard family)
Whitetop is common on alkaline, disturbed soils. It prospers in drought and is highly competitive with other species once it becomes established.
Growth Habit: Deep rooted perennial up to 2 feet tall, reproducing from root segments and seeds.
Leaves: Blue-green in color, lance-shaped. Lower leaves are stalked; upper leaves have two lobes clasping the stem.
Flowers: Plants have many white flowers with four petals, giving the plant a white, flat-topped appearance. Heart-shaped seed capsules contain two reddish-brown seeds separated by a narrow partition. Plants emerge in very early spring and have bloomed and set seed by mid-summer; prolific seed producer.
Roots: Whitetop reproduces perennially by its long taproot, by creeping rhizomes, and by broken root segments left in contact with the soil.
Other: Two other Cardaria species, lens-podded whitetop and hairy whitetop are common in the western U.S. with differences in seed capsules and fruit used to identify each species.