Brassicaceae - (Mustard family)

The initial rosette has long oval shaped leaves, blue green in color and mildly serrated.  Each rosette has several stems growing about 6-8 inches tall.  The upper leaves are smaller and have two lobes clasping the stem.

Each stem is topped by a profusion of small white flowers.  The flowers produce straw colored heart shaped seed capsules containing 2 seeds each. The plants appear very early in the spring, growing quickly to the seed stage.

Most plants are connected by way of underground spreading roots, and each plant develops a very deep tap root.

White Top reproduces perennially by the long tap root, by the creeping rhizomes, by broken root segments left in contact with the soil and also by prolific seed production. 

White top is prevalent in areas of generally alkaline or disturbed soil, it prospers in drought and easily overtakes native species. 

The following is courtesy of Weeds of the West:

A deep rooted perennial up to 2 feet tall, reproducing from root segments and seeds. Leaves are blue-green in color, lance-shaped. Lower leaves are stalked; upper leaves have two lobes clasping the stem. 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.

This perennial is common on alkaline, disturbed soils and is highly competitive with other species once it becomes established. It can be controlled effectively with herbicides. Two other Cardaria species, lens-podded whitetop (C. chalepensis L.) and hairy whitetop (C. pubescens (C.A. Meg) Jarmolenko) are common in the western U.S. with differences in seed capsules and fruit used to identify each species.

Non-standard name: whitetop.
(Courtesy of Weeds of the West)

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