Poorly rhododendron

[ErrolTheDragon]

I've got two rhododendrons in my back border. They must be about 25 years old now, so reasonably large but not enormous. One is fine, in flower now - the other was affected by the drought last year, I was hoping it would recover but it's still looking very poorly. I'm not sure what's best to do with it. The options I've thought of are:

1. try feeding and leaving it
2. cut back a bit (not sure where to)
3. cut back drastically- invasive rhododendrons hacked back in woodlands often seem to regrow, don't they?
4. get rid of it entirely... not sure if it would be possible to get the roots out to allow for planting something else.

Any ideas?

Does the poorly one have any flower buds on it ? Any new growth this year ?

If not, you might try cutting it back hard now, and giving it plenty food and water. It’s always worth a try and a lot easier than trying to dig it out.

Can you say more about what you mean by poorly? A photo would be good.

I'll try to take a photo tomorrow if it's not raining too much.
It lost quite a lot of leaf last year (many curled up, went brown and died), didn't make much new growth and now what leaf there is looks sickly. I don't think it's got flower buds (or much sign of the leaf growth you sometimes get instead of a bud, if you know what I mean).

www.glendoick.com/Rhododendron-Problems

Have a look at this.

Thanks - I'll take a close look at it tomorrow

I would not cut it hard back. You will lose the flowers for some years. I have a lot of Rhododendrons and to keep them in check I remove a little the very old wood ( usually it has silver stems) every couple of years.
I’d feed top dress with ericaceous compost and give them an ericaceous feed.
Hopefully photo of some of my Rhododendrons attached.

Photos ... the last of the healthy bush for comparison.

There's a lot of bare stem, quite a lot of which is silvery.

Mine suffered in the weather last year too. Very spindly and very few flowers. A couple of large ones completely died.

In photo 2 there is a stem that has no bud at the end. I’d take that out and any similar, but not more than a third of the entire shrub.
Then new growth should start.
Rhododendrons do not always flower at the same time, so those buds will flowers when the weather improves. A mulch and feed will help.

The plant puts energy into sustaining those old stems which are beyond flowering, rather than developing new growth.

It usually flowers pretty much at the same time as the other one, and quite a lot of the buds which do exist look dried up so I'm not holding out much hope for flowers this year - I'd rather get some healthier leaf growth going if possible.

At this point, taking out the 'blind' stems as you say is probably the best first step, along with a feed. Re mulching, my understanding is that Rhododendrons are shallow rooters which don't like being planted too deep so I've never mulched around them. I've probably got some rotted leaf mould lurking in a bag somewhere in a corner, would that do or something else?

The plant puts energy into sustaining those old stems which are beyond flowering, rather than developing new growth.

Yes... I think I may need to take out considerably more than a third to get rid of the sad leggy stems. I fear I may need to be rather more drastic now to get it in better shape for the longer term.

And I should probably check if the other one could do with any pruning after it's flowered - I've really not done that in the past.

Many thanks all for the advice!

Just a heads up OP based on my experience. I had two rhododendron which died inexplicably. They just gave up the ghost and died within weeks although mine did flower their hearts out before they died. I deduced eventually that they'd died of this: www.rhs.org.uk/advice/profile?pid=542 Phytophthora root rot.

This might not apply to you but thought I'd mention it in case it does.

Also, if you do dig it up check for honey fungus - black bootlace rhizomorphs will be present on the roots.

I did wonder about that (mentioned in link upthread) - I'll have a guddle round the roots this weekend to see if they look ok.

The purple ponticum rhododendrons (the sort you see wild in the countryside) are also a vector for a virus which is decimating rhododendron (and azalea?) stocks around the country.

If it was one of the purple ones, you're almost better to take it/them out fully and buying new. I need to do that to my front garden: I had 2 purple ponticums and one white one. Now that I know which one is the white one (I forget every year ) I need to hack away at and kill the other two. I'll then have the space and light to put in new and more interesting azaleas or rhodies

The other thing one rhodie specialist told me at Gardening Scotland one year was that sometimes rhodies, in drought years, will "sacrifice" one or two branches. Cut those ones away and the rest of the plant may well come away again

Phythopthora ramorum (Sudden Oak Death) is the disease carried by Ponticums that I was thinking of - mentioned in that Glendoik article.

It's a pink cultivar, similar if not identical to the healthy one. Similar in form to the common purple type though.

It's stopped raining, I might go out and have an initial hack.

That's interesting prettybird. I did read somewhere that the virus can take years to show up in plants which explains why mine seemed OK for a good few years then snuffed it really quickly.

That Glendoik article had good pictures of the effect of the disease. I was also given handouts with pictures at Gardening Scotland so that I could check out my rhodies (and the big collection my dad has). The problem with ponticum is that it can carry it but look ok, while the other rhodies, azaleas and pieris will be killed by it.

Feed it with an ericaceous plant food containing sequestered iron. Yellowing leaves are often caused by a lack of iron in the soil.

Feed it with an ericaceous plant food containing sequestered iron. Yellowing leaves are often caused by a lack of iron in the soil.

We do that - it's had the same as the healthy one.