Creeping St. John's Wort Aaron's Beard

Creeping St. John's wort is the tough, spreading groundcover that produces bright yellow, cup-shaped flowers, each one two to three inches across with a prominent central boss of golden stamens, from early summer into fall. The flowers are oversized for the plant, which grows just twelve to eighteen inches tall, giving the display a disproportionate visual punch. The semi-evergreen foliage is dense enough to suppress weeds once the colony fills in. Native to southeastern Europe and Asia Minor, it spreads aggressively by underground stolons into a thick, uniform mat.

In Western Washington, creeping St. John's wort is one of the most reliable groundcovers for difficult sites, dry shade, steep banks, poor soil, and the areas between and beneath trees where lawn fails and bare soil persists. It handles full sun to full shade with equal indifference and tolerates drought once established. No significant disease or pest concerns are tracked. The management consideration is containment: the stoloniferous spread is vigorous and will invade adjacent beds, paths, and lawn edges if not edged regularly. The stoloniferous spread will invade adjacent perennial borders without regular edging. For a large-scale groundcover application where aggressive spread is the goal rather than the problem, slopes, parking strip hell-strips, erosion control, it fills the space faster and with more visual payoff than most alternatives.