Posted on 08.30.21 by Harney SWCD

White Top (Lepidium Draba) is an herbaceous perennial native to central Europe, a member of the Brassicaceae family. This weed spreads quickly through its rhizomatous root structures; it also produces hundreds of seeds per plant, making it a double whammy. White Top grows to about knee height and is very thick.  The plants have leaves 1-3 inches in length and white flowers with dense canopy. The seed pods look heart shaped and the seeds are spicy tasting and can stay dormant in the soil for up to three years.

White Top can be found east of the Cascades in Oregon and throughout most of Idaho, typically in disturbed areas with deep sub moisture.  They have spread to rangeland and (surprisingly) to riparian zones.   Having White Top in rangeland is not good as the plant is toxic to cattle.

Once well established, the plant is difficult to control, though not super competitive. The root system can grow to 30 feet deep.  It can be hard to treat due to its rhizomes, but can be controlled through years of careful herbicide management.