Catagory 1

St. Johnswort

Hypericum perforatum

CLUSIACEAE (St. Johnswort family)

— herbaceous perennial that reproduces by vegetative buds and by seeds, can cause blistering and sensitivity to sun when ingested by white-skinned animals

IDENTIFYING CHARACTERISTICS

  • Yellow flowers may have black glands
    along the margins
  • Leaves have tiny transparent dots
    on the surface
  • Stems are reddish in color

This is a general table provided as a quick reference only. Treatments behave differently in different ecosystems.
What works in some areas of montana may not work in others. These treatments may also affect native and desirable plants.

St. Johnswort

cut mow
hand pull (wear gloves)
herbicide
biological control
reseeding
domestic animal
cultivate

effective

moderately effective-
effective in combination with other treatments
ineffective

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