Plant care
Iris 'Clarence'temperature & humidity
Iris 'Clarence'
More about iris 'clarence'
Ideal temperature for iris 'clarence'
Iris 'Clarence' is comfortable in any room a person is comfortable in, roughly -29 to 30°C (-20 to 86°F). The mistakes are micro-climates: a north-facing window on a frosty night, a south-facing windowsill in a summer heatwave, the standing draught between an opened kitchen door and the radiator behind it. Read the room around the plant, not the thermostat. Below roughly -29°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Iris 'Clarence' is comparatively hardy (USDA 3-9, 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 iris 'clarence'
Iris 'Clarence' sits happiest at around Ambient outdoor relative humidity. A garden perennial with no humidity needs. Good air circulation around the exposed rhizomes prevents bacterial soft rot and fungal leaf disease. 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.
Iris 'Clarence' temperature & humidity — frequently asked questions
What temperature is best for iris 'clarence'?
Iris 'Clarence' grows best between -29 to 30°C (-20 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 iris 'clarence' tolerate?
Iris 'Clarence' starts to suffer below roughly -29°C. It tolerates a cold dormant period within USDA 3-9, but a wet cold root zone is more dangerous than cold air.
What humidity does iris 'clarence' need?
Iris 'Clarence' prefers about Ambient outdoor relative humidity. A garden perennial with no humidity needs. Good air circulation around the exposed rhizomes prevents bacterial soft rot and fungal leaf disease.
How do I raise humidity for iris 'clarence'?
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 iris 'clarence' live outside?
Iris 'Clarence' is rated for USDA zone 3-9 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 iris 'clarence' care
In the UK? Keeping iris 'clarence' warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full iris 'clarence' care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.