Hardy Conifer Has Gentle Grace

This article was first published on 09 Jul 2012.

There is a common misconception that conifers are staid and unchanging. Many do change colour and mood with the seasons, with soft green spring growth maturing into yellows, oranges, plums, and browns. The juniper-like Russian arborvitae, Microbiota decussata, is one such example.

Tiger territory

Russian arborvitae shares the slopes of the Sikhote Alin mountain range on the east coast of Siberia with the Siberian tiger. There it grows from 35m above sea level to beyond the tree line. Although it was first recorded in 1921 it did not become readily available in cultivation until the 1980s.

Winter tan

Branches radiate from the centre, their tips nod gracefully forming mats of up to four metres across. Cones are tiny at only 2-3mm long. The ferny foliage is bright green during summer, undergoing a colour transformation to soft brown as the temperature drops. Like us, it needs sun for a deeper tan and a bit of shade during extreme heat. Coming from Siberia ensures that it is very hardy, but it can be fickle and die back for no apparent reason, especially when young plants are establishing. Branchlets can die if leaves are left piled on them for too long.

There is a large Microbiota, planted at least 25 years ago, on the top path of Dunedin Botanic Garden’s rock garden. Cuttings have been grown on and the offspring planted in the conifer cultivar collection at the north end of the rock garden where they have room to cascade over a rock wall.

Robyn Abernethy is the Rock, Water & Alpine Collection Curator at Dunedin Botanic Garden.