Russian arborvitae

Russian arborvitae: how do you recognise it?

Habit

Low and creeping, about 30–50 cm tall and up to 2 m wide; the tips of the branches curve slightly upwards.

Foliage

Small, scale-like leaves on flat, feathery sprays. Fresh green in summer.

Winter colour

Bronze-brown to coppery after the first frosts; it turns green again in March–April.

Cones

Small, round cones with a single seed. They are inconspicuous and have no ornamental value.

Roots

Fine and fibrous; it roots easily where branches touch the ground and likes well-drained soil.

Plants: April–May and September–October · Pruning: April

Why grow it?

• Grows in part shade and full shade, where most other creeping conifers turn thin and bare.
• Evergreen: a dense ground cover that brings bronze tones to the garden in winter.
• Very hardy, down to about −40 °C.
• Holds slopes and banks together and suppresses weeds once the mat has closed.
• Little work: no regular pruning needed and hardly any diseases.
• Pretty in a rock garden, on top of a low wall or as an edging along a path.

Russian arborvitae: where does it grow best?

• Sun, part shade or shade: shade is no problem. In full sun it needs extra water in dry summers.
• Well-drained soil: sand, loam or clay, acid to chalky, as long as water does not stand.
• Normal to dry; it tolerates wet feet badly.
• Allow 1–1.5 m per plant; for faster cover you can plant at 60–80 cm.

Light

Sun, partial shade and shade

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry or normal

Size

0.4 m tall, 2 m wide

Hardiness

Hardy (to -40 °C)

Goes well with

• Winter heath: Flowers in winter and early spring against the green and bronze mat.
• Barrenwort: Likes the same part shade and has delicate flowers in spring.
• Bergenia: Large, glossy leaves that contrast nicely with the fine foliage.
• Hosta: Broad, leafy plants beside the low mat in a shady corner.

Russian arborvitae: when and how to plant it?

Plant in April–May and September–October.

1. Plant in April–May or in September–October, when the soil is neither frozen nor waterlogged.
2. Dig a hole twice as wide as the root ball and just as deep. In heavy clay, work some sand or coarse grit into the soil for better drainage.
3. Set the plant at the same depth as in its pot and firm the soil well.
4. Leave 1–1.5 m between plants, or 60–80 cm if you want a dense mat quickly.
5. Water thoroughly straight away and keep the soil lightly moist during the first year.
6. Spread a layer of wood chips or bark around the plants against weeds, keeping it clear of the base of the branches.

Care

Water

In the first year water weekly in dry weather, afterwards hardly at all. In long dry spells in full sun, an occasional good soaking.

Feeding

Hardly needed. If you like, a handful of organic fertiliser or some compost in April.

Weeding

Weed regularly in the first year, until the mat has closed. After that it keeps weeds down itself.

Mulching

A thin layer of wood chips or bark keeps the soil moist while the plant has not yet closed up.

Debris

In autumn, clear fallen leaves and twigs from the mat: they hold moisture and can cause brown patches.

Tip: Bronze-brown branches in winter? That is normal and it will green up again by itself. Do clear fallen leaves from the mat so that it stays healthy.

Russian arborvitae: when to prune it?

Pruning months: April.

When: It rarely needs pruning. A light trim to shape is possible in April, when the new shoots start to grow.

How:

• Cut dead or brown shoots back into green wood.
• Shorten branches that are too long back to a side shoot with green scales, so the mat stays within its edge.
• Use sharp secateurs or shears; if a branch blocks a path, cut a little more rather than too little.

Caution: Do not cut into bare, old wood: like most conifers, it will not sprout again from there.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Cuttings

From August to October: semi-ripe cuttings of about 10 cm with a small heel of old wood, in a mix of sand and potting compost. Keep them moist in a cold frame or under plastic; roots form within a few months.

Layering

Branches that touch the ground often root by themselves. In spring or autumn, separate a rooted branch with a piece of root and plant it elsewhere.

Russian arborvitae: how does it get through the winter?

Hardy to −40 °C.

• Fully hardy, down to about −40 °C: no protection is needed in Belgian winters.
• The bronze-brown winter colour is normal. It turns green again in March–April and needs no pruning.
• In a pot it can stay outside; stand the pot on feet so that excess water can drain away.

Diseases and pests

• Root rot: Branches turn brown and die back in soil that is too wet and compact. Improve drainage, work sand into the soil and cut out dead branches.
• Drought damage: Brown, dry branches after a hot, dry summer, especially in full sun. Water generously and mulch.
• Brown patches in the mat: Usually caused by fallen leaves left lying. Clear them regularly and trim brown shoots.
• Winter colour: Bronze-brown in winter is not a disease: in spring it turns green again by itself.

Through the year

• March: Clear fallen leaves and winter debris from the mat.
• April: Plant. Light trim to shape. The winter colour turns back to green.
• May: Plant. Water after planting. Weed.
• July: Water in prolonged drought, especially young plants.
• August: Take semi-ripe cuttings. Water in dry weather.
• September: Plant. Take cuttings.
• October: Plant. Clear fallen leaves from the mat.
• November: Bronze-brown winter colour: normal.

Did you know?

• Russian arborvitae is the only species in its genus.
• The species name decussata means ‘crosswise’ and refers to the scale leaves arranged in crossed pairs.
• It was only scientifically described in the 1920s, after being found in the mountains of the Russian Far East.