02/18/2026
Different tree and shrub species have different ways of enduring winter weather.
Rhododendrons have a curious strategy in which the leaves curl into a tube and droop down when the weather gets cold. It can look alarming, but the leaves themselves remain quite green, pliable, and very much alive. The rolling up of rhododendron leaves is a survival mechanism called thermonasty, which is when a plant or plant part moves as a response to temperature change.
There’s been a lot of speculation around this behavior and why it is so effective for rhododendrons. It may reduce the load of snow or ice or keep leaves from drying out. It could also be related to photosynthesis. Rhododendrons are an understory plant and now that the deciduous overstory is bare, and the winter sun is lower in the sky, the plant is receiving more sunlight than it needs. The leaves may curl up to, in a way, avoid or at least limit photosynthesis.
From a plant health perspective, there are effective ways to supplement this strategy and help your rhododendron navigate winter.
Watering in the fall as well as applying a thin layer of mulch are both great practices to help rhododendrons, and all broadleaf evergreens, get through the cold weather.
If you’re interested in learning more about tree services and care of rhododendrons, visit our website at https://www.bartlett.com/tree-species....
Here you’ll find a range of expert tree and shrub advice as well as scientific research and information from The Bartlett Tree Research Laboratories.
https://youtu.be/N9E9SxUWz74?si=Gk5Szl9DZb-wB2Iq
Different tree and shrub species have different ways of enduring winter weather. Rhododendrons have a curious strategy in which the leaves curl into a tube a...