Rhododendron

Chelseajane · June 2021

The rhododendron which is new has had beautiful flowers but now all the leaves are sticky. What causes this and can I do anything about?

Fairygirl · June 2021

You may have had an infestation of aphids which produce honeydew. It can also happen if your rhodie is under a tree which drops any sap.
Have you got a photo though?

Lena_vs_Deer · June 2021

Photo would help for sure, but I doubt it’s an infestation. If it’s right after the bloom, then it’s more likely a glandular dew that new growth sends as a protective mechanism.
It’s easy to differentiate- touch it . If it’s insect stickiness it will be easily washed off your hands, if it’s glandular excretion - it will be really hard to scrape off and it will be decently water resistant, kind of like trying to scrape of taffy of your finger. Definitely doesn’t rinse, you have to get soap involved))

Rhododendron oils are very resin like in nature and protect them from being eaten by adult black vine weevil.

I really hate that stuff

every year it overlaps with dandelion fluff and for a week all rhododendron look “moldy” ))

Lena_vs_Deer · June 2021

For some more data went down to garden to take some photos. Here’s the part where glands sweat resin (marked inside blue ).
you can see it’s still sticky enough to hold a bunch of debris on it , but it starts to disappear.

But if it’s not that area (which stretches to bottom leaves), then as @Fairygirl said you may want to check on aphids. They usually cause leaf distortion and you can probably find some shells in a back of leaves .

Chelseajane · June 2021

Thank you both so much for replying. I'm afraid I don't know how to put a photo on here but I'm sure it is the resin. I had no idea that rhododendrons did this and I'm pleased that it's a good thing to protect it.

Ilikeplants · June 2021

I have sticky Rhodes too. If I try to deadhead flowers my fingers are so sticky but no aphids.

Fairygirl · June 2021

The new foliage is often slightly sticky underneath, so perhaps that's what the OP meant.

I've certainly never had stems being sticky from resin, but that might be due to climate and conditions here, and we do get vine weevils eating foliage, but it never affects them in any major way. They grow like weeds in this part of the world

Chelseajane · June 2021

I am in leafy Surrey

Lena_vs_Deer · June 2021

@Fairygirl I think it shows more on Rhodes that grow in shade and varieties with shiny new leaves vs “powdery” ones. Maybe shade makes them dry out slower?

Mine get really leggy new growth (a good fistful to grab with more to spare heh) and it’s all sticky haha … this thread reminded me yesterday that I had 2 big shrubs waiting to be deadheaded and sap was everywhere on my clothes that evening

I looked like instead of trimming a shrub I was wrestling with dogs on the ground

Fairygirl · June 2021

I can honestly say that I've never been covered in sap from deadheading any rhodo!

We can grow them in slightly sunnier sites than many other areas, because we have a generally cooler climate, but I can't say I've ever noticed a difference in the stickiness of foliage if in sun or shade. I just find the new foliage has a slight stickiness to it, but I don't really go around feeling it on a regular basis either!

Re the aphids -I don't actually get a lot here either. Birds [blue tits mostly] eat any that do appear, and possibly because our season is later in starting, plants aren't into growth as early, so the birds catch them at the right time. I know many people on the forum have reported very large infestations of them this spring though, on all sorts of plants, which is why I suggested that initially.
It's sometimes hard to determine a problem without any photos too

Rhododendron

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