Kansas Wildflowers and Grasses

ST. JOHN'S-WORT

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Hypericum perforatum L.

Ottawa County, Kansas

Perennial

Height: 1-3 feet

Family: Clusiaceae - St. John's-wort Family

Flowering Period: June, July, August

Stems:

Erect, several to many, often branched, ridged, glabrous, reddish.

Leaves:

Opposite, simple, sessile, oblong to linear, .5 to 1.5 inch long, less than 1/3 inch wide, glabrous, glandular-dotted; margins entire, rolling downward; tips pointed to rounded; upper leaves reduced.

Inflorescences:

Cymes, densely flowered, leafy-bracted, terminal.

Flowers:

Sepals 5, linear-lanceolate, unequal; corollas 3/4 to 1 inch wide, petals 5, to 1/2 inch long, bright yellow to orange-yellow, margins black-dotted; stamens numerous, in 3 clusters.

Fruits:

Capsules, egg-shaped, to 3/4 inch long; seeds small, pitted, black or dark brown.

Habitat:

Prairies, pastures, waste areas, and roadsides, most abundant in sandy soils.

Distribution:

Throughout except southwest corner of Kansas.

Toxicity:

Plants contain hypericin, which causes a photosensitive reaction following ingestion. This toxic reaction can be fatal to sheep and goats, which readily graze the plant.

Uses:

Native Americans used St. John's-wort to treat fevers, coughs, intestinal problems, nosebleeds, and snakebites.

Comments:

The dark spots on the petals are said to represent drops of St. John's blood. St. John's-wort has become a problem weed in the western portions of the U.S., where it is known as Klamathweed.

St. John's-wort flowers