Wondering why rhododendron leaves roll up in cold weather?
Rhododendron leaves may roll up in winter. Or, they may appear to flatten out. And, sometimes they look wilted. But, often when this happens, your shrubs are just fine.
When temperatures dip below plants can’t hide inside.
When temperatures plunge below freezing, garden plants have to protect themselves. And, evergreens like rhododendrons are no exception. In fact, evergreens may be more vulnerable than deciduous plants. And there are several reasons this is the case. Especially when we talk about broad leaf evergreens like rhododendrons.
When winter hits, outdoor plants face several challenges.
In winter, plants have to deal several combined assaults including:
- Heavy blankets of ice and snow.
- And desiccating cold winds.
- Plus, frozen solid soil.
So, to deal with these challenges, rhododendron leaves roll up.
- That’s because it’s difficult to take up water from roots in frozen soil.
- And that’s coupled with drying winds.
- So, these plants are being drained of moisture.
- Plus, they can’t replenish it.
- And, when plants dry out, they die.
Plus, maybe by rolling up and drooping it helps heavy snow and ice loads slide off of the leaves.
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What does water have to do with the leaves rolling up?
- Plants take up moisture in root systems and transport the water to their top growth.
- And they release some water from the underside of their leaves.
- Plus, as they release that water, more water is pulled upward from the roots.
- But, when the ground is frozen, plants can’t pull that water upward.
- So, they need to stop releasing water from the underside of their leaves.
And, that’s why rhododendron leaves roll up.
- By curling their leaves, rhododendrons stop releasing moisture from the bottom of the leaves.
- And, this stops the strain on the roots to pull moisture from the frozen Earth.
- Now, the process is more complicated, but you get the basic idea, right?
- The plant is simply protecting itself by conserving resources in a time of stress.
Other plants do similar things in heat.
- Have you ever noticed that a hydrangea wilts in the heat of summer.
- And no matter how much water you give it, it stays wilted.
- That is, until evening temperatures cool down.
- Then, those wilted leaves bounce right back.
- That’s because this is how hydrangeas stop releasing moisture from their leaves.
- So, rhododendron leaves curl up in cold to protect themselves.
- And, hydrangeas wilt their leaves to protect themselves similarly in hot times.
Once the stressful time has passed…
- Plants will uncurl or unwilt their leaves. And, usually, they’re just fine afterwards.
- But, that’s if the plant is adapted to the area. And that’s if the stressful weather isn’t something unusual.
- As well, this assumes that the curling issue was triggered for these reasons. (Curling leaves may happen for reasons that have nothing to do with temperatures.) So, do know that plant leaves can curl up, brown and die for other reasons too.