(Editor's Note: This article was originally published on November 29, 2008 Comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)
Siberian or Russian cypress, Microbiota decussata, is a relatively new introduction to our garden landscapes, but may well become the groundcover of choice for northern gardeners. Before we get into the specific attributes of the plant, a little botany and history on this plant might be appreciated. This conifer belongs to the family Cupressaceae and is somewhat closely related to junipers (Juniperus) and true cypress (Cupressus). In the wild, the plants hail from mountainous areas of eastern Siberia. Due to the remote location, this plant was not discovered until 1923. With all the secrecy between the former USSR and the western world, this plant only became known to the western world in the 1970s! Since its introduction to us, the plant has become increasingly popular.
The plant is quite low, generally between 20 and 50 cm but can spread up to 5 m. The foliage is evergreen and arranged in flattened sprays with scale-like leaves not unlike those found on Chamaecyparis. From a distance, this species looks much like a low-growing juniper. The cones are very small and rather insignificant. In fact, the female cones are the smallest of any conifer. Summer foliage is bright green but from late fall to mid-spring, plants turn purplish-brown. The winter colour provides a wonderful contrast in the winter garden, especially combined with heathers that have interesting winter foliage, golden-coloured conifers and ornamental grasses.
Close-up of the male and female cones.
This conifer is exceptionally hardy (zone 3 or sheltered areas of zone 2) and in the landscape, can easily rival the best spreading or creeping junipers. However, in my opinion, Siberian cypress surpass junipers since they do not suffer from the host of pests and diseases that plaque junipers. Full sun is best but they will tolerate more shade than junipers. They are not fussy as to the soil as long as it is well-drained and not too alkaline.
Siberian cypress produces overlapping sprays, lending a graceful appearance.
In the landscape they are premier choices for embankments, roadside medians and cascading over retaining walls. They are quite wind and salt tolerant so lend themselves wonderfully to coastal gardens. Their tolerance to drought makes them ideal choices for the mid-west where traditionally, junipers were the groundcover of choice.
Large mature Siberian cypress growing over a retaining wall and spilling over a pathway.
Unlike junipers which show tremendous variation in size, form and colour, Siberian cypress are remarkably consistent in habit and looks. So far only one cultivar has been selected. This one is called ‘Fuzz Ball' and has softer, fuzzier foliage than is typical of the species and a more compact, somewhat rounded habit, growing 30 cm by 100 cm. This selection would make an admirable conifer for the smaller garden.
So if you have a problem spot in a relatively open site and junipers are just not up to spec, then try growing Siberian cypress, the groundcover of the future!