Plant care
White Periwinkletemperature & humidity
Vinca minor 'Alba'
More about white periwinkle
Ideal temperature for white periwinkle
Aim for -20°C to 32°C (-4°F to 90°F) on the thermostat and you've handled the easy part. The hard part is the half-metre around the plant: window glass that drops to near-freezing on a January night, a radiator pumping out hot dry air, a draught from an opened front door. Move the plant 30 cm and you've usually fixed the problem. Below roughly -20°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
White Periwinkle is comparatively hardy (USDA 4–9, 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 white periwinkle
White Periwinkle sits happiest at around 40–75% relative humidity. Tolerates temperate outdoor humidity across its hardiness range. White-flowered forms can show more noticeable browning of petals in very humid or rainy conditions — this is cosmetic. No special humidity management required outdoors. 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.
White Periwinkle temperature & humidity — frequently asked questions
What temperature is best for white periwinkle?
White Periwinkle grows best between -20°C to 32°C (-4°F to 90°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 white periwinkle tolerate?
White Periwinkle starts to suffer below roughly -20°C. It tolerates a cold dormant period within USDA 4–9, but a wet cold root zone is more dangerous than cold air.
What humidity does white periwinkle need?
White Periwinkle prefers about 40–75% relative humidity. Tolerates temperate outdoor humidity across its hardiness range. White-flowered forms can show more noticeable browning of petals in very humid or rainy conditions — this is cosmetic. No special humidity management required outdoors.
How do I raise humidity for white periwinkle?
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 white periwinkle live outside?
White Periwinkle is rated for USDA zone 4–9 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 white periwinkle care
In the UK? Keeping white periwinkle warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full white periwinkle care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.