Plant care
Water Hedgetemperature & humidity
Didiplis diandra
More about water hedge
Ideal temperature for water hedge
Aim for 20-28°C (68-82°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
Water Hedge is comparatively hardy (USDA 5-9 (native to eastern North America; grown submerged/aquatic in temperate regions), RHS H4). 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 water hedge
Water Hedge sits happiest at around N/A (aquatic) or 70-85% emersed relative humidity. Fully submerged in aquarium culture. Emersed forms develop broader leaves and greenish colouration; high ambient humidity prevents wilting. 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.
Water Hedge temperature & humidity — frequently asked questions
What temperature is best for water hedge?
Water Hedge grows best between 20-28°C (68-82°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 water hedge tolerate?
Water Hedge starts to suffer below roughly 20°C. It tolerates a cold dormant period within USDA 5-9 (native to eastern North America; grown submerged/aquatic in temperate regions), but a wet cold root zone is more dangerous than cold air.
What humidity does water hedge need?
Water Hedge prefers about N/A (aquatic) or 70-85% emersed relative humidity. Fully submerged in aquarium culture. Emersed forms develop broader leaves and greenish colouration; high ambient humidity prevents wilting.
How do I raise humidity for water hedge?
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 water hedge live outside?
Water Hedge is rated for USDA zone 5-9 (native to eastern North America; grown submerged/aquatic in temperate regions) and RHS hardiness H4. 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 water hedge care
In the UK? Keeping water hedge warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full water hedge care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.