Plant care
Muir's Rhinephyllumtemperature & humidity
Rhinephyllum muirii
More about muir's rhinephyllum
Ideal temperature for muir's rhinephyllum
Temperature kills fewer muir's rhinephyllum 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 5–30°C; tolerates brief frost to -5°C when dry (41–86°F; tolerates brief frost to 23°F when dry) is fine; the spot you put the plant in matters more. Below roughly 5°C the damage starts — soft blackened patches, translucent leaves, sometimes overnight.
Cold tolerance & winter care
Muir's Rhinephyllum is frost-tender (USDA 8-11, RHS H2). It cannot survive a frost, so in most of the US and UK it lives indoors year-round or summers outside and comes back in well before the first autumn frost — once nights drop toward 10-12°C is the cue, not the first frost warning. Acclimate it over a week when moving between indoors and out so the leaves do not shock.
Humidity for muir's rhinephyllum
Muir's Rhinephyllum sits happiest at around Low (25–40% RH) relative humidity. Requires a very dry atmosphere for healthy growth. Avoid placement near humidifiers, dishwashers, or other moisture sources. Good air circulation helps prevent botrytis in cooler months. 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.
Muir's Rhinephyllum temperature & humidity — frequently asked questions
What temperature is best for muir's rhinephyllum?
Muir's Rhinephyllum grows best between 5–30°C; tolerates brief frost to -5°C when dry (41–86°F; tolerates brief frost to 23°F when dry). 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 muir's rhinephyllum tolerate?
Muir's Rhinephyllum starts to suffer below roughly 5°C. It is frost-tender and will be damaged or killed by a frost, so bring it indoors once nights fall toward 10-12°C.
What humidity does muir's rhinephyllum need?
Muir's Rhinephyllum prefers about Low (25–40% RH) relative humidity. Requires a very dry atmosphere for healthy growth. Avoid placement near humidifiers, dishwashers, or other moisture sources. Good air circulation helps prevent botrytis in cooler months.
How do I raise humidity for muir's rhinephyllum?
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 muir's rhinephyllum live outside?
Muir's Rhinephyllum is rated for USDA zone 8-11 and RHS hardiness H2. Outside that range it must come indoors before the first frost — treat any outdoor stint as a summer holiday, not a permanent home.
More muir's rhinephyllum care
In the UK? Keeping muir's rhinephyllum warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full muir's rhinephyllum care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.