Emerald Green Arborvitae (Emerald Arborvitae) care

Light

Aim for at least 4-6 hours of direct sun on the leaves. Thrives in full sun; requires at least 6 hours of direct sun daily for the densest, greenest growth. Tolerates partial shade but becomes open and lax. Full sun also helps the cultivar maintain its characteristic emerald colour through winter. If your only bright window faces south, that's perfect for emerald green arborvitae — same window any aroid would fry on.

Watering

Watering emerald green arborvitae: when the top 5 cm of soil is dry, roughly every 10-14 days for young plants. The number that matters isn't the day of the week — it's how dry the top 2-3 cm of the pot feels. A finger in the soil tells you more than a watering app. After every watering, tip the saucer. Once established, moderately drought-tolerant but performs best with consistent moisture. Young plants need regular deep watering in their first 2 years. Mulch to retain moisture. Avoid prolonged waterlogging.

Soil and pot

Emerald Green Arborvitae grows best in moist, well-drained, loamy soil. Adaptable to most well-drained soils including loam, clay-loam, and sandy loam. Tolerates a wide pH range (5.5–7.5). Avoid permanently wet or extremely dry, shallow soils. Incorporate compost at planting to improve water retention. 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

Emerald Green Arborvitae sits happiest at around 40-70% humidity and -30 to 30°C (-22 to 86°F). Tolerates a wide range of ambient humidity in temperate climates. Performs well in both continental and maritime climates. In very dry, hot summers, mulching and supplemental watering help prevent foliage browning. 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 emerald green arborvitae sparingly. Apply a balanced slow-release granular fertiliser in early spring. For hedging use, feeding twice a year (spring and early summer) maintains vigour after regular trimming. Avoid high-nitrogen feeds which cause excessively fast, weak growth. 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 emerald green arborvitae in the Growli community. Each is annotated with the most common cause so you know where to start.

• Bagworms — Spindle-shaped bags on foliage in summer; hand-pick in autumn/winter or treat with Bt in spring.
• Spider mites in drought — Yellow stippling on foliage in hot, dry conditions; water well and treat with insecticidal soap.
• Root rot — Overwatering or poorly drained soil; improve drainage and reduce watering frequency.
• Tip dieback — Cold winters or ice damage can cause tip browning; prune dead tips in spring and the plant usually recovers fully.

Companion plants

Emerald Green Arborvitae pairs well with Taxus baccata, Buxus sempervirens, Carpinus betulus, and Ilex crenata. These are species with similar light and water needs, so you can group them in the same room or on the same shelf and water as a batch.

Propagation

Take hardwood or semi-hardwood cuttings in autumn or late summer. Treat with rooting hormone and root in a gritty, moist propagation mix under protection. Roots readily; one of the easiest conifers to propagate from cuttings. 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

Emerald Green Arborvitae is mildly toxic to pets. Not individually listed by the ASPCA, but the Thuja genus contains thujone, which is toxic to cats, dogs, and livestock if foliage is ingested in quantity, causing gastrointestinal and neurological symptoms. Keep away from pets. 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.

Emerald Green Arborvitae deep-dive guides

Every aspect of emerald green arborvitae care, each with its own calibrated guide:

• Common emerald green arborvitae problems & fixes
• Emerald Green Arborvitae watering schedule
• Emerald Green Arborvitae light requirements
• Best soil mix for emerald green arborvitae
• Emerald Green Arborvitae fertilizing guide
• When to repot emerald green arborvitae
• How to propagate emerald green arborvitae
• How to prune emerald green arborvitae
• What's eating my emerald green arborvitae?
• Emerald Green Arborvitae growth rate & size
• Emerald Green Arborvitae cold hardiness
• Emerald Green Arborvitae temperature & humidity
• Is emerald green arborvitae toxic to cats & dogs?
• Is emerald green arborvitae toxic to cats?
• Is emerald green arborvitae toxic to dogs?
• All 17 Thuja varieties
• Getting emerald green arborvitae to bloom

Featured in these plant shortlists

Emerald Green Arborvitae qualifies for 4 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

• Best drought-tolerant houseplants — Houseplants that prefer to dry out — forgiving of forgotten watering and ideal for travel or busy weeks.
• Best flowering houseplants — Indoor plants grown for their blooms — selected from the flowering species in Growli’s plant-care library.
• Best houseplants for full sun — Houseplants that want direct sun — the species for a hot south or west-facing windowsill where shade-lovers scorch.
• Best houseplants for a cool room — Houseplants that tolerate cool conditions down to about 10°C — for an unheated spare room, hallway, porch or a home kept cool.
• Browse all 30 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Emerald Green Arborvitae is also known as Emerald Arborvitae, Smaragd Arborvitae, and Emerald Green Thuja.

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• All 11687 plant care guides in the Growli library