Plant care
Magnolia 'Susan'temperature & humidity
Magnolia 'Susan'
More about magnolia 'susan'
Ideal temperature for magnolia 'susan'
Temperature kills fewer magnolia 'susan' 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 -29 to 27°C (-20 to 81°F) is fine; the spot you put the plant in matters more. Below roughly -29°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Magnolia 'Susan' is comparatively hardy (USDA 4-8, RHS H6). 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 magnolia 'susan'
Magnolia 'Susan' sits happiest at around 40-60% relative humidity. Outdoor plant indifferent to ambient humidity in temperate gardens. Shelter from strong winds preserves the flowers; its late bloom means frost is rarely the threat it is for earlier magnolias. 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.
Magnolia 'Susan' temperature & humidity — frequently asked questions
What temperature is best for magnolia 'susan'?
Magnolia 'Susan' grows best between -29 to 27°C (-20 to 81°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 magnolia 'susan' tolerate?
Magnolia 'Susan' starts to suffer below roughly -29°C. It tolerates a cold dormant period within USDA 4-8, but a wet cold root zone is more dangerous than cold air.
What humidity does magnolia 'susan' need?
Magnolia 'Susan' prefers about 40-60% relative humidity. Outdoor plant indifferent to ambient humidity in temperate gardens. Shelter from strong winds preserves the flowers; its late bloom means frost is rarely the threat it is for earlier magnolias.
How do I raise humidity for magnolia 'susan'?
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 magnolia 'susan' live outside?
Magnolia 'Susan' is rated for USDA zone 4-8 and RHS hardiness H6. 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 magnolia 'susan' care
In the UK? Keeping magnolia 'susan' warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full magnolia 'susan' care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.