WSU Clark County Extension

PNW Plants Searchable, categorized images

Creeping St. John's wort

Scientific name: Hypericum calycinum

Type:Groundcovers evergreen
Plant Requirements
Zone:5 to 9
Sun:Full to partial sun
Plant Characteristics
Height:1 ft
Width:2 ft
Bloom:Summer flowers
Bloom Time:July to August
Bloom Color:Yellow
Additional Characteristics



Wildlife value

Description Creeping St. John’s wort, often known as Aaron’s beard, is one of the most highly adaptable ground covers in the trade as it will spread vigorously to quickly cover a hillside or embankment, even in conditions of shade.

A stoloniferous evergreen groundcover that grows to a height of 12” and a width of 24". It bears simple opposite arranged leaves which are ovate-oblong in shape and up to 2”-4” long. The leaves are rich green in color in the summer but light yellow in the shade.

The most notable feature of St. John’s wort is the presence of 3” wide bright yellow flowers. Flowers consist of 5 petals surrounding a dense tuft of protruding yellow stamens that resemble an old fashioned shaving brush. Flowers are borne in groups of 2-3 and appear from July through August

Easily grown in average, medium, well-drained soil in full sun to part shade. When it is grown in complete shade the plants simply don’t flower. To maximize flowering give Aaron's beard as much sun as possible.

Rust can be a problem when the plants are grown in wet climates. If it does appear, the best defense against further rust is sanitation of infested plant parts.
For assistance, contact Dr. Charles Brun (, (360) 397-6060 5701
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