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Plant care

Siberian Carpet Cypress (Russian Arborvitae) care

Microbiota decussata

Also called Siberian Carpet Cypress, Russian Arborvitae, Siberian Cypress.

RHS H7USDA 3-7Mildly toxic to petsIndoor 0.5 m tall

Watering rhythm

Medium indirect light (a couple of metres from a window)

Moderate — once established, largely drought-tolerant

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Light

Medium indirect light (a couple of metres from a window)

Soil

Well-drained, moderately fertile loam, sand, or clay

Humidity

Low to moderate (30–60%)

Temp

-40°C to 30°C

Pet safety

Mildly toxic to pets

Mature size

0.5 m tall

Care at a glance

Light

Siberian Carpet Cypress wants the spot a few feet back from a sunny window — bright enough to read a paperback at noon, but the sun never falls directly on the leaves. One of the few conifers genuinely shade-tolerant; performs well in partial shade to full shade, making it ideal beneath deciduous trees. Full sun is tolerated in cool, moist climates but causes foliage to bronze more heavily. A faint hand shadow at midday is the right amount; a sharp dark shadow means it's getting direct sun and probably too much.

Watering

Water siberian carpet cypress moderate — once established, largely drought-tolerant. The actual day count varies with pot size, light, and season — the finger test (or lifting the pot to feel its weight) is more reliable than a fixed calendar. Empty any drainage saucer afterwards so the pot isn't sitting in water. Water weekly during the establishment period (first 2 years); once rooted, this species shows excellent drought tolerance and rarely needs supplemental irrigation in UK climates.

Soil and pot

Siberian Carpet Cypress grows best in well-drained, moderately fertile loam, sand, or clay. Remarkably adaptable to most soil types including poor, stony, or clay soils provided drainage is adequate; pH tolerance from 4.5 to 7.5 makes it highly versatile in both UK and US gardens. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Siberian Carpet Cypress sits happiest at around Low to moderate (30–60%) humidity and -40°C to 30°C (-40°F to 86°F). Native to high-altitude continental conditions with cold, dry winters; handles both the humid summers of the US Northeast and the milder, wetter UK climate with equal ease. If you keep the room above year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed siberian carpet cypress sparingly. Feeding is rarely necessary in reasonable garden soil; if growth is very slow, apply a balanced granular fertiliser at half the recommended rate in early spring only. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on siberian carpet cypress in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Root rot in waterlogged soil — Although tough in most conditions, sustained waterlogging causes root rot and sudden whole-plant collapse; this is most common when planted in clay-bottomed depressions. Raise the planting area or incorporate coarse grit to improve drainage before planting.
  • Spider mites in hot, dry conditions — Prolonged drought and high temperatures can trigger two-spotted spider mite (Tetranychus urticae) infestations, causing bronze stippling of foliage. Increase irrigation and apply a miticide or insecticidal soap spray; the problem typically resolves with cooler weather.

Propagation

Semi-ripe cuttings 8–10 cm long taken in late summer, treated with rooting hormone and placed in a cold frame or unheated greenhouse, root reliably over winter. Layer low-growing stems by pinning them to the soil surface — roots typically form within one growing season. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Siberian Carpet Cypress is mildly toxic to pets. Microbiota decussata is not individually listed on the ASPCA Toxic and Non-Toxic Plant database. As a conifer producing resinous compounds, ingestion of foliage may cause mild gastrointestinal irritation in cats or dogs. Classified as mildly-toxic out of caution pending a confirmed ASPCA listing. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Siberian Carpet Cypress care — frequently asked questions

What is the common name for Microbiota decussata?

Microbiota decussata is most commonly called Siberian Carpet Cypress, but it is also known as Siberian Carpet Cypress, Russian Arborvitae, Siberian Cypress. The names refer to the same species, so care instructions for Siberian Carpet Cypress apply identically to anything sold as Russian Arborvitae.

How much light does siberian carpet cypress need?

Siberian Carpet Cypress grows best in medium indirect light (a couple of metres from a window). One of the few conifers genuinely shade-tolerant; performs well in partial shade to full shade, making it ideal beneath deciduous trees. Full sun is tolerated in cool, moist climates but causes foliage to bronze more heavily.

How often should I water siberian carpet cypress?

Water siberian carpet cypress moderate — once established, largely drought-tolerant. Water weekly during the establishment period (first 2 years); once rooted, this species shows excellent drought tolerance and rarely needs supplemental irrigation in UK climates. The finger-test (or lifting the pot to feel its weight) beats a fixed weekly calendar because pot size, light, and season all change how fast the soil dries.

Is siberian carpet cypress toxic to cats and dogs?

Siberian Carpet Cypress is mildly toxic to pets. Microbiota decussata is not individually listed on the ASPCA Toxic and Non-Toxic Plant database. As a conifer producing resinous compounds, ingestion of foliage may cause mild gastrointestinal irritation in cats or dogs. Classified as mildly-toxic out of caution pending a confirmed ASPCA listing.

What USDA hardiness zone does siberian carpet cypress grow in?

Siberian Carpet Cypress is rated for USDA zone 3-7 and RHS hardiness H7. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Siberian Carpet Cypress deep-dive guides

Every aspect of siberian carpet cypress care, each with its own calibrated guide:

Featured in these plant shortlists

Siberian Carpet Cypress qualifies for 5 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

Related guides

Siberian Carpet Cypress is also known as Siberian Carpet Cypress, Russian Arborvitae, and Siberian Cypress.