How to identify — This plant forms low growing mats (2 inches or less). These mats often blowout from the center or side, exposing the interior of the cushion formation and substrate beneath. The leaves are evergreen and slightly waxy. They are deep purple or red throughout the winter, becoming green during the growing season, and turning purple-red again early in the fall. The tiny leaves form tight rosettes, which usually surround a flower or leaf bud. The flowers are large in comparison to the leaves. The 5 white fused petals extend on a short stalk above the mat. The fruit eventually dries and forms a capsule that splits open to allow seed dispersal. This species is often associated with other cushion and subshrub plants such as alpine azalea (Loiseleuria procumbens), Lapland rosebay (Rhododendron lapponicum), alpine bilberry (Vaccinium uliginosum), and bearberry willow (Salix uva-ursi). When not in flower, this species could be confused with an associated cushion plant alpine azalea, which also has tiny leaves that form low cushion mats. Alpine azalea can be distinguished by its looser leaves, which do not form the characteristic tight rosettes of diapensia. When in flower, they are easily distinguished by the pink petals of alpine azalea.  

Habitat/Distribution — Within the alpine zone, diapensia is generally found at higher elevations and in exposed areas. Regionally, it is restricted to alpine areas of New York, Vermont, New Hampshire, Maine, and Canada. It is also found throughout boreal and arctic regions of the world including Greenland, and northern Europe. A different variety (var. obovata rather than our local var. lapponica) is found in northern Asia, northwest Canada, and Alaska.

Ecology — This plant is especially well adapted to exposed areas and extreme climate conditions. Its low growth form of tight cushions helps to reduce heat and water loss from wind, and physical damage from blowing snow and ice. The waxy leaves also help to retain water. Early in the season, the leaves have a purple-red color. This pigment (anthocyanin) absorbs potentially harmful ultraviolet radiation and converts it into heat. Although Diapensia is very resilient, it grows extremely slowly and is therefore slow to recover from impacts. Keep an eye out for a rare form of diapensia with numerous petals instead of the normal 5 petals. This form has a slightly later flowering time.

Environmental Change Issues — While most plant and animal species have the ability to shift their distributions north or south in response to climate change, alpine habitat in the Northeast is distributed as isolated islands surrounded by inhospitable spruce-fir and northern hardwood forests. They are limited to shifts in altitude in response to climate change rather than latitude. Because diapensia is a high elevation species within the alpine zone, suitable habitat may be reduced or eliminated if alpine areas shrink in response to climate change.