What is wrong with my Rhododendron?

[Chasingsquirrels]

Had it 2 or 3 years, the leaves started doing this last year.

In ericaceous compost, topped up on spring and ericaceous slow release feed in summer.
Not overwatered nor underwatered.
No obvious pests.

In same position as a camelia and skimmia japonica so I don't think it's the location.

Hello Chasingsquirrels,

I don’t know what part of Great Britain 🇬🇧 you are in but here we have been experiencing cold winds recently around the country.

Rhododendrons will roll their leaves inwards to reduce water loss which they loose through the stomata which are on the underside of their leaves. Some evergreen plants do suffer in the winter and spring as they do hold on to their leaves which they will continually loose water through unlike plants that lose their leaves 🍂 in autumn. Evergreen plants are also more at risk if the soil is frozen then they are unable to extract water from it.

I hope the above helps

Happy gardening
Thesustainablegardener 🧑‍🌾

Thanks thesustainablegardener.
I'm in East Anglia, just outside Cambridge.
It is in a very sheltered position which rarely gets any wind, and has been like that since last summer so I don't think it is really a winter/spring thing.
The other two ericaceous evergreens around instead are very healthy.

Sorry OP, but this looks like what inexplicably happened to mine after many years quite happy in its spot. It eventually died despite all attempts to save it I never worked out what was wrong.
PP is right they do that with their leaves to preserve water... can't help but notice that pot is quite shallow/small... in your shoes I'd repot to something bigger I think. Perhaps it's struggling to get enough water in from that amount of soil, especially if it's pot bound.
Good luck and hopefully it's not afflicted with whatever killed mine!

Hello Chasingsquirrels,

I second bulliedbyslugs comment about repotting your rhododendron in a larger pot with some fresh ericaceous compost. Your rhododendron is definitely suffering from water stress due to it rolling its leaves which could also indicate there being more roots than soil/compost. If you do repot your rhododendron don’t forget to tease out some of the roots as I suspect it may be slightly pot bound.

Happy gardening
Thesustainablegardener

Interesting, I haven't thought that the pot might be too small for the size of the plant.
It definitely isn't underwatered, and has recently been top dressed with fresh compost.
I'll see whether it looks root bound and try a larger pot

Could there be vine weevils in the pot? They might be eating the roots and so the plant can't take up water.

Maybe, I'll take it out and have a look at the soil & roots.

That plant is very very thirsty. Bigger pot and more water may help. I would put it in the ground and hope it recovers

It definable needs a bigger pot. That's the problem.

Repot it and give it an intensive liquid feed to help with the stress of being reported.

I have a lot of rhododendron and azaleas but all planted in the ground. You can get really dwarf varieties (max height 1.5ft) which can be kept in pots as you know their maximum size - some of my rhododendron are 6ft tall after 20 years having started at about 1ft when I bought them!

Okay, I've taken it out of the pot.

• definitely NOT pot bound. In fact when I teased the external compost layers off to find the roots it has barely grown out from the original rootball/pot size (smaller) from when I got it.
• the soil is not at all dry, and hasn't been. In fact having taken it out I'm now wondering is it has been overwatered.
• definitely no evidence of vine weevils grubs.

It it weird that most reposnse are saying the same thing, but it really really isn't water deprived or root bound.

I've potted in up, in a similar sized but deeper pot, with some fresh ericaceous compost, and I'll see what happens.

Oh, and I've got other Rhododendrons.

• a dwarf that is basically ground cover which is in a shallow pot and does need potting up this year.
• a much bigger one which is in a bigger pot.

Both older that this one and both fine.

https://www.gardenanswers.com/shrubs/rhododendron-leaf-curl/

generally it’s cold winds, cold temp, lack of light. You can prune it back.

My two rhododendrons in pots looked exactly the same until this morning. Couldn’t work out why and I went though the same check list as you, OP. This morning I decided to cut them back to basically stumps. One just broke off in my hand as the roots had withered to nothing. The other appears to have roots so it may revive, but I’m not holding my breath. It’s a mystery!

There’s a thing where the roots don’t seek out the edges of the pot but just circle around in the centre. Various techniques to try to prevent this, one is to do a deep cut into rootball. I’ve never dane anything that drastic.

Don’t feed it till it’s recovered from moving. Stressed plants are better without food

Hello again Chasingsquirrels,

You may think about emailing a rhododendron grower or society which you could find online for their advice on what the problem may be due to.

Happy Gardening
TheSustainableGardener