Plant care
Degroot's Spire Arborvitaetemperature & humidity
Thuja occidentalis 'Degroot's Spire'
More about degroot's spire arborvitae
Ideal temperature for degroot's spire arborvitae
Temperature kills fewer degroot's spire arborvitae plants than you'd think. What kills them is the micro-climate within a normal-temperature room — a leaf pressed against single-glazed winter glass, the hot dry updraft directly above a radiator, the cold blast from an AC vent. The thermostat reading at -37 to 30°C (-35 to 86°F) is fine; the spot you put the plant in matters more. Below roughly -37°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Degroot's Spire Arborvitae is comparatively hardy (USDA 3-8 (very narrow columnar), RHS H7). Within that range it tolerates a cold dormant spell outdoors; outside it, grow it in a container you can move under cover or overwinter in a cool but frost-free spot. Hardiness assumes an established plant in well-drained soil — a wet, cold root zone kills far more plants than cold air alone.
Humidity for degroot's spire arborvitae
Degroot's Spire Arborvitae sits happiest at around Ambient outdoor humidity relative humidity. An outdoor columnar conifer indifferent to humidity; good airflow between plants reduces fungal needle blight in humid regions. The usual low-humidity tell is crisp brown leaf tips and edges while the soil moisture is fine — a sign the air, not the watering, is the problem. If you need to raise it, the reliable methods are grouping plants together, standing the pot on a tray of damp pebbles (the pot above the waterline, never in it), or running a small humidifier in winter when indoor heating dries the air most. Misting is the least effective — it raises humidity for minutes, not hours.
Degroot's Spire Arborvitae temperature & humidity — frequently asked questions
What temperature is best for degroot's spire arborvitae?
Degroot's Spire Arborvitae grows best between -37 to 30°C (-35 to 86°F). Keep it out of cold draughts, off freezing windowsills in winter, and away from the hot dry air directly above radiators — the extremes matter far more than the average room temperature.
How cold can degroot's spire arborvitae tolerate?
Degroot's Spire Arborvitae starts to suffer below roughly -37°C. It tolerates a cold dormant period within USDA 3-8 (very narrow columnar), but a wet cold root zone is more dangerous than cold air.
What humidity does degroot's spire arborvitae need?
Degroot's Spire Arborvitae prefers about Ambient outdoor humidity relative humidity. An outdoor columnar conifer indifferent to humidity; good airflow between plants reduces fungal needle blight in humid regions.
How do I raise humidity for degroot's spire arborvitae?
Group it with other plants, stand the pot on a tray of damp pebbles (kept above the waterline), or run a small humidifier in winter. Misting only helps for a few minutes, so it is the weakest option for a plant that genuinely needs more humidity.
Can degroot's spire arborvitae live outside?
Degroot's Spire Arborvitae is rated for USDA zone 3-8 (very narrow columnar) and RHS hardiness H7. Within that range it can stay outdoors; outside it, grow it in a moveable container and protect the roots from a wet, cold winter.
More degroot's spire arborvitae care
In the UK? Keeping degroot's spire arborvitae warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full degroot's spire arborvitae care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.