Hypericum densiflorum

Hypericum densiflorum earns the name densiflorum, densely flowered, in high summer, when the twiggy shrub disappears under rounded clusters of small golden flowers, each one a starburst of fine stamens above five clean yellow petals. Bees work the blooms from July into September, and as the show fades the narrow dark green leaves turn a warm yellow, giving way in winter to reddish, lightly peeling bark on the older stems.

The common name reaches back to the old world and the Midsummer feast of Saint John the Baptist on the twenty-fourth of June, when the European kin of this shrub, Hypericum perforatum, comes into bloom. Country folk hung the flowering sprigs above doorways and holy images to turn away storms and ill spirits, and the genus name records the custom: Hypericum joins the Greek hyper, above, with eikon, an image. The native American species carry the name and something of the reputation, and several were minor remedies of Cherokee and settler households in the past, valued as astringents and wound herbs, though the celebrated medicinal St. John's Wort remains the European plant.

In the wild Hypericum densiflorum ranges across the eastern United States and west into Texas, keeping to acidic ground: the seepy edges of streams and ponds, wet meadows, and boggy flats, though the shrub will also colonize surprisingly dry, open sites. Spreading quietly by underground stolons, a single plant thickens over time into a dense twiggy colony, which is exactly the habit that makes the species useful where a gardener wants cover rather than a lone specimen.

Set in a sunny to lightly shaded bed, bushy St. John's Wort reads as a rounded, leafy mound taller than wide, an easy anchor for a moist border, a rain garden, or the transition between lawn and pond. The summer flowers arrive when many shrubs have finished, so a group carries color through the quiet middle of the season and feeds pollinators while doing so. Pair the shrub with buttonbush, swamp azalea, winterberry, and native grasses in damp ground, or let a colony hold a difficult wet bank unaided.