Plant care
Monkey flowertemperature & humidity
Mimulus × hybridus
More about monkey flower
Ideal temperature for monkey flower
Temperature kills fewer monkey 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 5–21°C (41–70°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
Monkey flower is comparatively hardy (USDA 6–9 (as a cool-season annual or short-lived perennial), 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 monkey flower
Monkey flower sits happiest at around 50–80% relative humidity. Prefers moderate to high ambient humidity. In hot, dry air, plants desiccate and fail quickly. Group pots together, mist lightly in the morning, or place on damp gravel trays to raise local 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.
Monkey flower temperature & humidity — frequently asked questions
What temperature is best for monkey flower?
Monkey flower grows best between 5–21°C (41–70°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 monkey flower tolerate?
Monkey flower starts to suffer below roughly 5°C. It tolerates a cold dormant period within USDA 6–9 (as a cool-season annual or short-lived perennial), but a wet cold root zone is more dangerous than cold air.
What humidity does monkey flower need?
Monkey flower prefers about 50–80% relative humidity. Prefers moderate to high ambient humidity. In hot, dry air, plants desiccate and fail quickly. Group pots together, mist lightly in the morning, or place on damp gravel trays to raise local humidity.
How do I raise humidity for monkey 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 monkey flower live outside?
Monkey flower is rated for USDA zone 6–9 (as a cool-season annual or short-lived perennial) 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 monkey flower care
In the UK? Keeping monkey 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 monkey flower care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.