Linnaea borealis americana

eRare, for a semi-shady rock garden.

From taiga and tundra ecosystems in the far north. Twin flower or Corpse rash grass! It is medicinal in many northern cultures especially for skin complaints. An evergreen subshrub with slender above ground appressed stems. The plants are stoloniferous after c. 5 years, spreading up to 50 cm per annum, ultimately a colony may be several metres across; from horizontal stems arise many vertical stems, vegetative and reproductive, to a maximum height of 15 cm. Leaves opposite, scallop-toothed. Twin flowers arise, fragrant.  Such a rare plant.  It prefers dappled shade and low levels of disturbance, often colonising mossy rocks, tree stumps, etc. There are three distinct subspecies, but little has been done to fix the names into distnct species.  One reason so many botanists are reluctant to accept an expanded Linnaea  may be that L. borealis, for so long the sole species, has become inextricably linked with Linnaeus himself. This beautiful plant of the high-latitudes became Linnaeus’s emblem even within his own lifetime; he was clearly rather fond of it as Bean recounted: ‘In his Critica Botanica (1737), pp. 80–81, Linnaeus himself commented: “Linnaea is a plant of Lapland, lowly, insignificant, disregarded, flowering but for a brief space – from Linnaeus, who resembles it” (Sir Arthur Hort’s translation, p. 64, 1938)’ (Bean 1981).

Like many plants from similar environments Linnaea can be extremely difficult to establish in gardens, and very easy to kill. It requires nutrient-poor, moist but well drained acid soils under dappled shade, in a cool climate. There was at one time ‘a well known colony’ in the Sunningdale Nurseries in Berkshire, UK, but it later died: ‘A load of manure was dumped on it’ (Bean 1981)! Although the climate in southern England is probably no longer appropriate, cool woodsy conditions such as existed in those Berkshire pinewoods still give the best chance of success if the aim is to establish a meaningful swathe; in the absence of such conditions, a cool, shaded position in a rock garden is worth trying, so long as it won’t dry out. Curiously, Bean noted that plants of North American provenance tended to grow better in Britain (Bean 1981), perhaps its more southern reach in North America has endowed some populations with greater heat tolerance than their Eurasian counterparts. The provenance of cultivated material may not be apparent, however.