By Piers66
Surrey,
United Kingdom 
Pruning advice for Rhododendrons?
I have half a dozen bushes that have got a bit overgrown / leggy. I don't know what varieties they are, but they're different types.
Late last year I pruned some of the stems on one bush, where I could clearly see buds some way down the woodier parts of the stems. Those buds have produced new growth (though I understand it may be another year before they flower, due to pruning in winter).
I'd like to prune some of the other bushes, but can't see any obvious buds on the stems to prune back to. These bushes have rougher stems, with bark that's peeling off more than the one that I did prune.
Are they there anyway?
If I cut back below the first set of leaves will they produce new growth?
The plants are probably at least 10 years old.
Any advice gratefully received.
20 Jul, 2013
Answers
Thanks for the advice.
I'm not really looking to cut them back that drastically, though.
They're in a bed with azaleas along the front row, so rather than reduce to 6 inches, I'm thinking of more like 3 to 4 foot high. Currently they're up to 6 foot high, though given that they don't grow straight up that's maybe 10 or 12 foot of growth. That is, they've spread out a long way from the roots.
The important question for me, is whether the varieties where I can't see buds further down the stems do in fact have them, dormant under the surface, or not at all. In other words if I pruned back to 3 foot would I just end up with a load of bare woody trunks?
23 Jul, 2013
I have cut back old Rhododendrons in my parents garden in winter.
I will quote from the website below:
"Rejuvenation pruning involves the careful cutting back of each primary branch of the plant's framework. Rhododendrons often have three or more main branches rising from the crown of the plant. These branches, called primary branches, form the basic scaffold of each shrub. Each branch is cut at a different height to produce a staggered arrangement that will make the shrub look natural when the new shoots mature.
To see if your shrub can handle such a hard pruning, cut only one of the main branches back to 6 inches. Cut the others back to a height you are sure is healthy, say 2 feet. If new growth emerges from the 6-inch cut, you can cut back the rest of the shrub following year and be confident in its return."
http://www.finegardening.com/how-to/articles/three-ways-prune-rhododendrons.aspx?id=86688
20 Jul, 2013