Rhododendron problem

billy5 · May 2023

Because I don't have the right acid soil I have a rhododendron growing in acid soil in a large dustbin. The plant is healthy enough and it has grown well over the years. It's now about 8ft high X 8ft wide. I water and feed at the appropriate time to produce flower buds. The plant looks very healthy and has produced an abundance of flower buds. Up to now non of these buds has flowered. Which, going on past history. is very late. Each bud is sticky to the touch. I have no idea whether this is normal or not?

Does anyone have any idea why this plant hasn't flowered yet? Is the sticky buds a sign of anything? Or is it just the cold start to the season. Many other rhododendrons in my area, 5miles north of Chester, are well into bloom.

bédé · May 2023

Sticky buds suggests to me that they are leaf-and-stem buds. Are they thinner and more pointed than you have noticed with flower buds. You should get flowers on these next year.

Blame last year's dryness at a critical time. Sometimes rhodies will over-flower, and then take a year off.

Take a trip to Ness Gardens and see what is happeneing there.

billy5 · May 2023

Thanks, but the stickiness is on all the FLOWER buds not leaf buds. I know the difference. Not last years dryness as I water in a very well drained pot. I suspect, information off internet, that it's some form of insect honeydew fungus? Does anyone know whether there is any cure for this problem? Or, should I take drastic action, and destroy the plant?

bédé · May 2023

No, not drastic action. Not yet.

Aphids secrete honeydew, which is basically sugars and so sticky. Sometimes a black fungus can grow on this. Any insecticide would work, but when it happens on my camellias, I just rub them off. It has never happened to my rhodies.

Patience!

Crazybeelady · May 2023

Mine get sticky and I think it is from aphids, I see them on there! They're just opening up now which is about a month later than last year but slightly earlier than 2021.

Fairygirl · May 2023

Rhodos all flower at different times, although most are around this time of year, but many places had drought conditions last year, so any shortage of water at the critical time can set shrubs back, especially anything evergreen in a container, because rainwater needs to be heavy and prolonged to get through the foliage canopy. If you're hand watering, it's important to make sure the soil in the container hasn't got dried out at any point, as that becomes extremely difficult to re hydrate properly again.

Sometimes aphids honeydew can gum up flower buds -like they do with roses and peonies. If you carefully wipe it off, that should help

Do you have a photo @billy5 ? That will also help.
If it's otherwise healthy, then it shouldn't be too big a problem to sort.

billy5 · May 2023

Fairygirl, thank you so much for your advice but I'm afraid the problem could be a lot more serious than what you suggest? The plant is normally well into flower at this time of year. I will try and wipe stickiness off each bud with a wet rag. But, I fear that the plant has been infected by some sort of insect which causes some sort of fungus. I'm no expert but have got this info off the internet. The unopened buds have a black 'stain'. If flower buds do not open I thought about cutting them all off if they are infected. Is this advisable?

Sorry! I can't send a picture as I'm totally clueless with regards computers and I wouldn't know how.

billy5 · May 2023

Thank you all for the advice. I tried wiping stickiness off with a wet cloth. A thankless task, too many buds, and if anything buds were more sticky after they had been wiped. I dissected one bud and it appears to have a healthy flower growing inside. Obviously the stickiness is preventing the flower from opening. I sprayed each bud with a strong blast of water but to no avail still very sticky.

I will leave plant now and see what happens but I'm not very optimistic. Once again, thank you,

Fairygirl · May 2023

Lots of plants are later than usual, so that isn't necessarily a problem.
However, it's also impossible to advise properly without seeing it. There's even a chance it could be rotting, as it's in a large container and if soil clogs drainage holes you can easily have the opposite scenario to it drying out, which is also very common- as I mentioned earlier.

It could well be something more serious, but that's also likely to be as a result of stress being caused for another reason.

Re photos - the icon above the text box [for your post] that looks like hills is the one for uploading photos if you want to try that.

Mrs-B3-Southampton,-Hants · May 2023

My rhodo has had buds covered in a black 'stain', but not sticky, for several years. I picked each one off and gradually the problem lessened and nothing this year. Not all the plant was affected and other buds flowered normally.

bédé · May 2023

billy5 said:

Obviously the stickiness is preventing the flower from opening.

No. It's not obvious.

Horse chestnut buds, for eg, are very sticky; they are called "sticky-buds". They always open with no problems. It's possibly some form of insect deterent.

A bit more optimism and a bit more patience!!!

Rhododendron problem

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