Plant care
Pecan 'Sumner'temperature & humidity
Carya illinoinensis 'Sumner'
More about pecan 'sumner'
Ideal temperature for pecan 'sumner'
Temperature kills fewer pecan 'sumner' 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 -15 to 38°C (5 to 100°F) is fine; the spot you put the plant in matters more. Below roughly -15°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Pecan 'Sumner' is comparatively hardy (USDA 6-9 (late ripening needs a long season), RHS H5). 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 pecan 'sumner'
Pecan 'Sumner' sits happiest at around Ambient (outdoor) relative humidity. An outdoor orchard tree; ambient humidity is not a care variable. 'Sumner' carries good scab tolerance, letting it crop reliably in the humid Southeast where many cultivars fail. 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.
Pecan 'Sumner' temperature & humidity — frequently asked questions
What temperature is best for pecan 'sumner'?
Pecan 'Sumner' grows best between -15 to 38°C (5 to 100°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 pecan 'sumner' tolerate?
Pecan 'Sumner' starts to suffer below roughly -15°C. It tolerates a cold dormant period within USDA 6-9 (late ripening needs a long season), but a wet cold root zone is more dangerous than cold air.
What humidity does pecan 'sumner' need?
Pecan 'Sumner' prefers about Ambient (outdoor) relative humidity. An outdoor orchard tree; ambient humidity is not a care variable. 'Sumner' carries good scab tolerance, letting it crop reliably in the humid Southeast where many cultivars fail.
How do I raise humidity for pecan 'sumner'?
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 pecan 'sumner' live outside?
Pecan 'Sumner' is rated for USDA zone 6-9 (late ripening needs a long season) and RHS hardiness H5. 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 pecan 'sumner' care
In the UK? Keeping pecan 'sumner' warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full pecan 'sumner' care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.