Hypericum kalmianum

Hypericum kalmianum is the tidy, cold-hardy member of the clan, a compact rounded shrub barely knee-high, densely branched, with narrow bluish-green leaves set in pairs along curiously four-angled stems. From July into September the plant disappears under bright golden flowers, each a shallow cup filled with a full boss of stamens, the bloom arriving in the heat of summer when the color is most welcome.

The name honors Pehr Kalm, the Finnish-Swedish naturalist who traveled British North America in the mid-eighteenth century and sent plants home to his teacher, Carl Linnaeus. Linnaeus returned the favor by attaching Kalm's name to this shrub and to the mountain laurels, the genus Kalmia, so a single traveler is remembered twice over in the flora. Above that personal history sits the ancient genus name, Hypericum, from the Greek hyper and eikon, above and image, recalling the old habit of hanging flowering St. John's Wort over doorways and icons at Midsummer to keep trouble out.

In the wild Hypericum kalmianum belongs to the Great Lakes, threading the shorelines of Ontario, Quebec, and the states that ring the lakes, from Michigan and Wisconsin to New York and Ohio. The shrub favors damp, open, often calcareous ground: interdunal swales, the sandy borders of ponds, moist meadows, and the flat limestone pavements known as alvars, among the rarest habitats in North America. That upbringing makes for a plant of remarkable toughness, at home in cold, wind, and lean, gritty soil.

Woodlanders offers Kalm's St. John's Wort thanks to Mr. Richard Lynch of Staten Island, New York, and the shrub earns the introduction. Compact and neat without shearing, the plant works as a low informal hedge, a foundation filler, a front-of-border mound, or a rain garden shrub, and the summer gold reads cleanly against the blue-green foliage. Cold-hardy far to the north, Kalm's St. John's Wort pairs easily with little bluestem, coneflowers, and other sun-loving natives on well-drained ground.