Plant care
Bishop's flowertemperature & humidity
Ammi majus
More about bishop's flower
Ideal temperature for bishop's flower
Temperature kills fewer bishop's flower 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 5–27°C (41–81°F) is fine; the spot you put the plant in matters more. Below roughly 5°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Bishop's flower is comparatively hardy (USDA 2–11 (cool-season annual), RHS H3). 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 bishop's flower
Bishop's flower sits happiest at around 40–70% relative humidity. Adapts well to a range of ambient humidity levels typical in UK and US gardens. In hot, dry conditions the flowering period is shortened; adequate soil moisture compensates for low humidity. 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.
Bishop's flower temperature & humidity — frequently asked questions
What temperature is best for bishop's flower?
Bishop's flower grows best between 5–27°C (41–81°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 bishop's flower tolerate?
Bishop's flower starts to suffer below roughly 5°C. It tolerates a cold dormant period within USDA 2–11 (cool-season annual), but a wet cold root zone is more dangerous than cold air.
What humidity does bishop's flower need?
Bishop's flower prefers about 40–70% relative humidity. Adapts well to a range of ambient humidity levels typical in UK and US gardens. In hot, dry conditions the flowering period is shortened; adequate soil moisture compensates for low humidity.
How do I raise humidity for bishop's flower?
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 bishop's flower live outside?
Bishop's flower is rated for USDA zone 2–11 (cool-season annual) and RHS hardiness H3. 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 bishop's flower care
In the UK? Keeping bishop's flower warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full bishop's flower care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.