Microbiota decussata

The Russian arborvitae is a low-growing, prostrate, mat-forming, dwarf evergreen conifer that is frequently known as the Russian arborvitae or Siberian cypress. It is a shrub-like ground cover that grows from 6 to 18 inches tall and spreads up to 12 feet wide. The bright green scale-like or awl-shaped foliage is feathery, soft, and arranged in flat sprays. In the fall and winter, the foliage transitions to bronze-purple, copper bronze, to red. The fruits are tiny, round, berry-like cones that have woody scales. It has the habit of creeping juniper, and the foliage is similar to the genus Thuja or arborvitae. Unlike creeping juniper, the branch tips of the Russian arborvitae nod downward, and it is also more shade tolerant.

The Russian arborvitae is native to the Primorye Territory of Russia and the Siberian mountains. It was first seen in Vladivostok, Russia in 1921.

The genus name, Microbiota, is derived from the Greek word, micro, meaning "small,' and Biota, which is the former name of a related genus Platycladus. The specific epithet, decussata, references the arrangement of the foliage which means the adjacent pairs of leaves are rotated about 90 degrees. The common names reference its native range and its similar characteristics to other members of the cypress family.

This needled evergreen prefers full sun to partial shade with moist, well-drained soils. It is more shade tolerant than groundcover junipers. It will perform best in cool summer climates and is cold hardy from USDA hardiness zones 3 to 7.  This conifer is intolerant to hot and humid summers, poor drainage, or excessive wetness. No pruning is required, and it requires very little maintenance.

Consider this plant in cooler summer climates as a groundcover, especially for slopes, banks, or hillsides. It may also be used as a specimen and for borders, foundation plantings, or rock gardens.

Seasons of Interest:

Foliage:  Year-round                Fruit:  Fall

Quick ID Hints:

• low-growing, prostrate, mat-forming evergreen conifer
• feathery, soft, bright green scale-like or awl-shaped foliage with branch tips that nod downward and are arranged in flat sprays
• fall foliage bronze purple, copper bronze, or red
• tiny, spherical, yellow to brown, berry-like cones

Insects, Diseases, and Other Plant Problems: The Russian arborvitae is generally disease and pest free; however, it is Intolerant to poorly drained soils, and hot, and humid climates. Root rot may develop in excessively wet areas.

VIDEO created by Ryan Contreras for “Landscape Plant Materials I:  Deciduous Hardwoods and Conifers or Landscape Plant Materials II:  Spring Flowering Trees and Shrubs” a plant identification course offered by the Department of Horticulture at Oregon State University