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in Problem solving
Is my Rhododendron dead ...or not?
It has lost all but perhaps 10 leaves which are producing flowers.
I have had it for about 7 years in a pot on my patio. Last year it had a lot of cabbage catepillars on it.
Help! It's my favourite, a beautiful lilac colour.
What can I do?
Could it have suffered from lack of water? Might it have outgrown its pot and need new compost? Or did the leaves go yellowish last year, a sign of chlorosis? Give it a tonic such as sequestrene plus.
OK ta, I'll give that a go
I water it religiously so I don't think it's that.
sounds like a food problem.. buy an ericaecious feed, (bought from pound shops!) mix up in a watering can then water in. Having said that, you are watering with rainwater yes? Because these symptoms could be from using tap water over a prolonged period of time. Remember your chemistry, this plant loves acid conditions, most tap water is treated to slightly alkali, it is very slight, but enough to give trouble over time. Also remember that these plants can suffer from ph change from recent buildings due to the lime leeching from the mortar on walls etc recently built. good luck anyways, hope my advice helps.
just read in pots, so most defo from the tap water, if you have no water butts, store the water for a few weeks from the tap in an open container, ph should adjust naturally.
If it is due to hard water then a quick soak with sequestrene + is your surest fast response. It will also deal with other nutrient problems. You can then leave it for a few months to recover before thinking about a bigger pot and new compost.
Thank you so much for the advice!
I will get sequestrene + today to start bringing my Rhododendron back.
Virago, before the leaves dropped did they look like rolled up cigars? Rolled up tight and then rapid leaf drop? Are the dead leaves in a tightly rolled-up state?
If so this is likely to be phytophthora and overwatering is a contributory factor. It's been cold, we've had a winter and early spring of heavy rain and the roots can't cope esp if plant is in shade. Sequestrene won't make a difference to this.
Could be vine weevil damage, rhodos suffer just as much as other plants from this pest. I would get some Provado into the pot ASAP.
If you have Provado Vine Weevil Killer you could add some just to be sure. If not, it's expensive stuff, so you might be able to lift the plant out of the pot and have a look to see if you can see any vine weevil grubs and see if you can see any healthy root ends, which should be whitish.If so then it's probably not vine weevil. When I have had one of my potted camellias attacked by vine weevil, by the time it looked sickly on top the damage under the surface was terminal, so if your rhodie is showing signs of growth it's probably nutrients / chlorosis.
Thank you all so much - will check it out this weekend.
Keep us posted. Like to know what you find. I'm always curious as to the cause of poorly plants
I suspected vine weevil damage in a similar case recently....as goldilocks suggested I checked it's roots...but it was unaffected. Not sure you can get Provado vine weevil killer now in the GC etc.....it's now banned.....but you still might get it online. If not use nematodes....if you see those grubs.
Provado Vine Weevil Killer and Provado Ultimate Bug Killer are not affected by the recent restrictions, which will apply for two years. .
It's a bit complicated,but three neonicotinoid insecticides have been banned, including one (imidacloprid) that used to be used in these two products, but the formula was changed a couple of years ago, to an ingredient called thiacloprid. The main impact will be on the agricultural industry, where imidacloprid is widely used.
The only 'domestic' product affected is Provado Lawn Grub Killer.
Had a look at the roots today and it looked like moss I couldn't make out the roots at all. I didn't want to scrape away the 'moss' too much incase I damaged my plant more. Have repotted it and now we wait to see.
The foliage that was there has been growing very well ... just the rest of the plant is bare
Will keep posting updates
The roots of rhododendrons are fibrous. At least you didn't see any vine weevil grubs. Keep it in light shade and take care not to overwater it.
It may well grow leggy. They don't tend to break from old wood unless pruned. If you could be sure that it is healthy I would be tempted to prune it back now to stimulate new growth from lower down. Now is the best time to prune rhododendrons. The alternative is to let it grow and flower next spring. and then cut it back - it just means another year before you can get it into a good structural shape.
Please take a look at the photos, how far back should I prune it? As you can see there are only a few leaves on it ...sadly.
Oh dear, it does look as if it is barely clinging on to life. There is a lot woody tissue that will need to be kept alive, and only a few leaves to produce the energy to do it. I think if you leave it then it doesn't stand much chance. I think i can see a few leaves close to the base. I would cut back everything else, and leave these. Put it somewhere sheltered and hope for the best. Provided that whatever brought it to this state (disease, overwatering, vine weevil) is now gone then there is a good chance it will recover. If you have just given it a rhododendron feed then don't give it anything else, other than rain water when it needs it.