Hypericum perforatum - St. John's Wort
Family Hypericaceae
St. John's wort is a rhizomatous perennial that spreads via seed and
creeping
rhizomes. It is prevalent throughout the Willamette Valley.
It
can become weedy in Oregon nursery stock, although I rarely see it
well-maintained
fields.
The most unique identifying characteristic of the plant are its leaves.
Each
leaves contain a number of translucent glands, which when held up to
the
sun make it appear as if the leaf were perforated (hence the name).
Leaves are sessile and arranged oppositely along the stem.
Stems are reddish in color. They are also flattened, and the
direction
in which the stems are flattened rotates 90 degrees at each node.
Flowers are yellow and occur in clusters called cymes.
Each flower has 5 petals and numerous stamens.
Return to the Weed Species Page
Return to the Weed Management Homepage
Email comments to James
Altland
