The best time to prune is just after flowering. Late growth that results from pruning at this time of year would be very vulnerable to winter damage, even in Z8.

If you're asking if you can prune all the way back to the growth at the 2 foot area, the answer is probably. It will take many years for it to regrow and start blooming again, however. Keep in mind, too, that rhododendrons can be unpredictable in their response to being drastically cut back. Without knowing the particular variety of rhododendron, we're really in the dark.

It's possible that the white spots are some form of fungus, but I've never seen this on leaves. A photo would be a big help.

Hi Lucy,

Your rhododendron is already beginning to solve the problem by already sending up shoots. If you prune back the top, all the strength in the roots will go to these new shoots. It should respond very well.

When you say you have been fighting weevils, I assume you are referring to leaf damage. The main damage from strawberry root weevils and black vine weevils is to the roots which goes unseen. Damage to the leaves is just cosmetic. So be sensitive to any weakness that may be caused by root problems. The main symptom is chlorosis (yellowing of leaves between green veins) and you didn't mention that, so I assume the weevil damage is not terrible. The best way to get rid of weevils is to make sure that no branches touch the ground and then put Tanglefoot on the stems above where they come out of the ground. Weevils live in the ground and crawl out every night and climb up the stems to feed on the leaves. So by putting the Tanglefoot between the leaves and the ground will rid you of them.

Aka's advice to wait until right after it blooms in Spring to prune is excellent advice.

There are a number of possibilities for the white spots:

If a leaf has brown areas with white spots, it probably has a local fungal infection of Pestalotia rhododendri. This is seldom controlled with fungicides and is best mitigated by good sanitation and avoiding excessive moisture. So pruning would help with that.

Cottony white masses on underside of leaves are probably egg masses of the Cottony Azalea Scale, Pulvinaria floccifera. They are up to 1/2 inch long. Control is the same as with other scale insects. Since timing is critical, a systemic works best.

Small white spots on the underside of leaves and small white flies on under-surface of leaves is also an indication in infestation of Azalea Whitefly (Pealius azaleae.) and Rhododendron Whitefly (Dialeurodes chittendeni.). They are more prevalent on certain varieties and on plants grown in protected areas. These small white flying insects look like an aphid with wings and suck on the underside of foliage, leaving white spots where it has been. Heavy infestations cause the margins of terminal leaves to cup. These infested leaves will eventually turn yellowish and appear wilted. The lower leaves become covered with honeydew, followed by sooty mold (a black coating). To check for the presence of whiteflies, shake the terminals of white azaleas to flush out adult whiteflies which look like tiny white moths. Examine the lower surfaces of leaves for the presence of nymphs, which are flat, yellowish green, and resemble scale insects. All stages occur on the under sides of leaves. This whitefly is usually limited to varieties of the snow azalea, Rhododendron mucronatum. If the infestation is light, little or no plant symptoms are evident, and if beneficial insects are present, spray the undersides of leaves with insecticidal soap or a horticultural oil at the 2%summer rate. If the infestation is heavy use a registered residual insecticide such as Malathion, Diazinon or Orthene. Dick Murcott, of Long Island, had a simple remedy to control the numbers of white flies. He would hang pieces of stiff plastic or 12" square metal sheets painted with a bright yellow/orange paint and then covered with petroleum jelly or any clear, sticky material. The white flies will fly to the colored material and get stuck in the sticky stuff!

Here is a link that might be useful: Tanglefoot

Thank you so much for your help! (I have photos on my phone but don't know how to get them onto this site.) Since one of you says I can trim it and the other says it might stress it, I'm afraid to cut it back to the newer growth close to the ground. It bloomed 2 months ago. Is it too late to trim about 1/3 of it? A lady at a garden store said the white spots might be powdery mildew and recommended Neem oil. What do you think? I am spraying the ground with beneficial nematodes tonight to kill any root weevil larvae that I didn't get last year. There is no yellowing of the leaves but 2 rhodies next to this one have died, so I want to be sure to get rid of all of the larvae and adults. I used Bayer for the adults this year and it seemed to work very well. I will try the tanglefoot.
Thanks again for your help!

Thank you so much for your help! (I have photos on my phone but don't know how to get them onto this site.) Since one of you says I can trim it and the other says it might stress it, I'm afraid to cut it back to the newer growth close to the ground. It bloomed 2 months ago. Is it too late to trim about 1/3 of it? A lady at a garden store said the white spots might be powdery mildew and recommended Neem oil. What do you think? I am spraying the ground with beneficial nematodes tonight to kill any root weevil larvae that I didn't get last year. There is no yellowing of the leaves but 2 rhodies next to this one have died, so I want to be sure to get rid of all of the larvae and adults. I used Bayer for the adults this year and it seemed to work very well. I will try the tanglefoot.
Thanks again for your help!

It is perfectly safe to cut out dead material anytime. It would be best to cut live material in the early spring. If you aren't concerned about loosing bloom, March or April is the best time to prune. If you want to save the bloom, prune immediately after it blooms.

Thanks again for all of your help. I wish you lived nearby. I would pay you (if you were willing) to help me save this rhody.

It is perfectly safe to cut out dead material anytime. It would be best to cut live material in the early spring. If you aren't concerned about loosing bloom, March or April is the best time to prune. If you want to save the bloom, prune immediately after it blooms.