Plant Information: Lepidium latifolium

Perennial pepperweed (also known as perennial peppercress, tall whitetop) is a non-native invasive plant that is originally from southeastern Europe and Asia. This noxious weed has spread at an alarming rate throughout portions of the western United States over the last 15 years. It establishes large monocultural stands that exclude and compete with all other plant species. In terms of grazing it is low in protein and difficult for grazing cattle to digest. Perennial pepperweed stems originate from large below-ground roots that allow rapid growth of shoots. Shoots remain in a rosette form for several weeks before the internodes elongate and stems are produced. Rosette leaves may persist through winter months in mild areas with infrequent frost. Dense clusters of white flowers are produce from late spring through the summer. Although perennial pepperweed produces viable seed, there has been little evidence of seedling germination in the field. Its main method of spread appears to be the lateral production of new shoots via the root system. This plant is major problem in parts of central and northern California, and other western states, but it is presently only scattered within San Diego County. We want to get rid of this noxious plant before it really takes a hold. If you see this plant, PLEASE report it!

• General Biology and Control Methods: TNC Element Stewardship Abstract (outside link)
• Lepidium latifolium photo gallery


POSTER
Download a perennial pepperweed poster with pictures and description of the plant (available in two sizes):
    8.5"x11" size, 2.2 MB JPEG file
    11"x17" size, 3.2 MB JPEG file
OR for a limited number of copies, contact wma@smslrwma.org. NOTE: If your browser automatically opens this file it will be a HUGE size on your screen. Right click on the link and select "Save Target As". You will then be able to open the JPEG file with Photoshop or some other program to view and print it.

If you see this plant, please report the location to wma@smslrwma.org or Bill Winans, County Agriculture (858) 694-2777. If you are uncertain of your identification of this plant contact us or the County Agriculture Office. Also check out our images of perennial pepperweed (see above).