Kalmia microphylla aka Bog Laurel

Kalmia microphylla is a small evergreen shrub in the heath family, Ericaceae. Its native range runs from Alaska through Canada and the western United States. It grows in subalpine or subarctic climates. Kew lists its growth form as a subshrub. This is a low, woody plant rather than a tree. It is not native to Britain or Ireland. The leaves stay on the plant through the year. Its small size and low form contrast with its bright summer flowers.

The shrub has many branches and often forms a low mat. Stems may fall outward rather than stand upright. Virginia Tech gives an upper height of 1.5 feet [0.46 metres]. Most plants remain much shorter than that. This makes the stated height an upper limit, not a usual size. The bark is gray-brown and mostly smooth, with a few shallow cracks. Young twigs bear fine hairs. As they age, they become smooth and turn reddish brown to gray. Two edges or lines run along the slender twigs. The rounded buds are reddish brown.

Leaves grow in opposite pairs along the stems. Each blade is narrow, ranging from lanceolate to narrowly oblong. The leaves measure half an inch to one inch long. Their edges roll over, giving each blade a distinct outline. The leaf texture is firm and leathery. Upper surfaces are glossy and dark green. The undersides look almost white and carry fine hairs. This marked contrast helps distinguish the two leaf surfaces. The evergreen foliage and closely branched stems define much of the plant's low form.

Flowers appear in summer, in clusters at the branch tips. Each bell-shaped bloom measures about three-eighths of an inch across. The flower colour ranges from pink to purple. Small woody capsules follow the flowers and ripen in early autumn. Each capsule is rounded, slightly urn-shaped, and divided into five parts. The fruits remain on the branches through winter and into spring. Thus, the fruit lasts well beyond the summer flowering season. The low branches carry evergreen leaves as well as these lasting capsules. Together, these features give the shrub a clear identity across the seasons.