Plant care
Hydrangea 'Endless Summer'temperature & humidity
Hydrangea macrophylla 'Endless Summer'
More about hydrangea 'endless summer'
Ideal temperature for hydrangea 'endless summer'
Temperature kills fewer hydrangea 'endless summer' 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 10-24°C (50-75°F) is fine; the spot you put the plant in matters more. Below roughly 10°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Hydrangea 'Endless Summer' is comparatively hardy (USDA 4-9, RHS H5). 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 hydrangea 'endless summer'
Hydrangea 'Endless Summer' sits happiest at around 50-70% relative humidity. Average outdoor humidity is fine. It dislikes hot, dry wind, which scorches leaf margins and wilts flowers; a sheltered spot with steady moisture matters more than ambient humidity. Indoor pot plants prefer cool, humid air. 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.
Hydrangea 'Endless Summer' temperature & humidity — frequently asked questions
What temperature is best for hydrangea 'endless summer'?
Hydrangea 'Endless Summer' grows best between 10-24°C (50-75°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 hydrangea 'endless summer' tolerate?
Hydrangea 'Endless Summer' starts to suffer below roughly 10°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 hydrangea 'endless summer' need?
Hydrangea 'Endless Summer' prefers about 50-70% relative humidity. Average outdoor humidity is fine. It dislikes hot, dry wind, which scorches leaf margins and wilts flowers; a sheltered spot with steady moisture matters more than ambient humidity. Indoor pot plants prefer cool, humid air.
How do I raise humidity for hydrangea 'endless summer'?
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 hydrangea 'endless summer' live outside?
Hydrangea 'Endless Summer' is rated for USDA zone 4-9 and RHS hardiness H5. 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 hydrangea 'endless summer' care
In the UK? Keeping hydrangea 'endless summer' warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full hydrangea 'endless summer' care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.