Lythrum hyssopifolium

Lythrum hyssopifolium_hyssop loosestrife_ JM Di Tomaso
Photo courtesy from Joseph DiTomaso

Synonyms: L. adsurgens, L. hyssopifolia

Common names: hyssop loosestrife; grass poly; hyssop lythrum

Lythrum hyssopifolium (hyssop loosestrife) is a perennial forb/herb (family Lythraceae) that invades wetlands. It occurs in seasonal wetlands, ditches, and cultivated fields, especially rice fields. L. hyssopifolium often grows on exposed mud, tolerates some salinity, but is sensitive to heavy frost.

Rating: Moderate

Cal-IPC Resources

  • Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.
  • CalWeedMapper - Statewide maps, climate models, and reports.
  • Cal-IPC News - Our quarterly newsletter. Each issue is available as a pdf.
  • Cal-IPC Symposium Proceedings - Presentations and papers from our annual Symposium.
  • Don't Plant a Pest! - Select your region to find non-invasive alternatives to ornamental species. Also see our statewide brochure on trees.

    Other Resources

    • USDA PLANTS database -
      Federal database with information on identification and distribution, and links to websites in individual states.
    • Jepson Online Interchange for California Flora - Information on taxonomy, biology, and distribution from the UC Berkeley Jepson Herbarium.
    • CalFlora - Distribution information by county based on submitted observations and herbarium specimens.
    • Encycloweedia - Plants rated as noxious weeds by the California Department of Food and Agriculture.
    • CalPhotos - Images of plants taken mostly in California.

    Symposium Presentations

    • Bauder, E. T. (1996). Exotics in the southern California bernal pool ecosystem. California Exotic Pest Plant Council Symposium '96. San Diego, CA.
    • Quinn, L., B. Davis, et al. (2006). Does horse manure harbor invasive plants? Cal-IPC Symposium. Rohnert Park, CA.

    Cal-IPC News Articles

    • None for this species.