Hypericum perforatum is native to Europe, western Asia, and northern Africa. It was introduced to Hawai’i for ornamental and medicinal purposes. The common name is St. Johns Wort. This plant is listed as noxious weeds in several states. When buried in the soil, a seed from this plant can last ten years. A single adult plant can produce up to 100,000 seeds per year.
Description and Dispersal:
- Hypericum perforatum is a herbaceous perennial with yellow flowers with 5 petals. This plant has many branches and tiny olive shaped leaves.