I think in your zone I'd grit my teeth. Winter or early spring (sacrificing flowers) in mild climates, Spring after hard frost is no longer threatening in areas where winters are severe. And as long as you've waited, you may as well enjoy the flowers, prune immediately after flowering if possible :)

Cold damage is more severe around pruning wounds than on unpruned parts of plants, and Spring pruning gives new growth from dormant buds the longest possible period to mature before cold weather again sets in.

You can usually cut a healthy established azalea down to within a few inches of the ground and have it break from dormant buds just under the remaining bark - while understanding this is not without any risk at all.

You can usually cut a healthy established azalea down to within a few inches

===>>> hmmmm ... foremost.. i have never done this ... but when i saw this comment.. and the z8 ... my first thought was.. wow ... i am not sure that would work in my z5 ...

the hardy azalea i have.. just arent that vigorous ...

if i were to SPECULATE .... i would tend toward a 3 year plan to rejuvenate the plants.. taking out the most offending problematic branches ... and see how they react next year.. see if they actually do sprout dormant buds..

if so.. by next fall ... i would remove more ...

i would just hesitate.. in our zone.. to chop it all down near the ground .. UNLESS you are so frustrated.. you dont care if it lives .. in which case .. if you do.. it will thrive with vigor.. since it has that big root system ... and nothing to do with all that energy.. but resprout ... go figure on that.. and it might be a function of snow cover insulating it ...

i hope we get some other voices from the 2 zones ... if i am wrong .. so be it ... i have just NEVER seen a 5 to 6 foot azalea in z5 MI ... though maybe i just wasnt noticing [of course... next spring i will see a million of them.. lol ]...

ken

Yes, the height of these in zone 5 continues to amaze me, Ken. Actually, they are over 5'-6"--and that's with yearly pruning.

I don't want to lose these under any circumstances so I think I'll try a combo method. Will prune now the branches nearest the steps and walk. In the spring, I'll prune some to a few inches and others as much as I dare.

I haven't seen azaleas pruned to within a few inches of the ground but I have done it with yews and inkberries and have seen ironclad rhododendrons, esp Roseum Elegans, treated this way. Results mixed except for the rhody, which was better than ever.

Here's one of the better informational sites - Steve has gardened in both Pacific Northwest and closer to your climate, Pennsylvania

See How to Grow, Pruning, Severe. It seems regionally you may find heavy pruning less successful if your plants are sited in a high degree of shade.

Here is a link that might be useful: Hennings Rhododendron pages

Do as Morz8 said, cut to 1-2' in a Spring, and don't worry about anything :-)

Thanks for that very useful link and for the advice. Here's hoping.

If these plants are important to you, wait until spring. Too great a chance of killing large portions of them if you prune now.

Last March I hired a landscaper to remove an overgrown juniper hedge. At the height of their chopping frenzy, the workers cut down a mature Martha Hitchcock azalea as well as a PJM Rhododendron. Cut them down to a 3 inch stump. I just assumed them lost.

They both grew back to almost a foot tall. This, despite the hottest driest summer in history, removal of their protecting shade and no extra water or anything from me. They're tougher than you think. I plan to transplant them this weekend.

Just a follow-up report. I did cut back one third of these 'Mme. Butterfly' azaleas and prune the rest pretty severley. Fertilized heavily this spring. They are coming back amazingly. Vigorous new growth everywhere.

Even all along the trunks, new growth is sprouting. I will continue to cut these back a third each year. So far, so good. Thanks again for the advice.

Here's the annual report on the Great Azalea Project, in case anyone needs to do likewise.

Success! We are now in Year 2 of the three-year plan. Lots of new growth and very heavy flowering this year. As flowering is recently over, I will cut back the second third, if you follow me, of the azaleas.

I fertilized heavily last year. Have to admit it had been years. I was thinking mature shrubs didn't need it and I was wrong. They are really looking good and responding well to the heavy pruning/feeding. Yippee--and thanks!

i am one to usually suggest that shrubs rarely .... if ever need fert ...

but you are undergoing extreme rejuvenation pruning.. reducing canopy .. with absolutely NO INSULT to the root mass..

and then equate all success to increased fert ...

i am sure it didnt hurt..

but i would suggest that the plants VIGOR is as much.. if not more affected.. by the rejuvenation.. as your feeding it ...

there is no answer to who is right.. i just didnt want you ruling out one for the other ...

you are basically turning grandpa into a teenage stud.. and it may not have anything to do with what he eats ... its vigor ... the ability to have so much energy.. that he WANTS to go run that mile.. not whether his bones will crack if he hoiks himself off the lazyboy.. lol ...

what did you use for fert??? and how heavy ...

ekn

So here is the annual report on the azalea rejuvenation project, for those who may need to do the same. It is a wild success, I am happy to say as these shrubs mean a lot to me. We keep pruning out old growth very low or almost to the ground. And there is so much new growth that it is hard to keep up with them.

We have had ample rain this year and last. And I have fertilized with 5-10-10 granular fertilizer which I use on all flowering shrubs, when I use anything. Another big change is that we took down some large trees so the area is sunnier than it has been in years which azaleas in my area need.

This is a very vigorous cultivar--Mme. Butterfly--so I don't know if all azaleas would react the same but this project has been a success.

super..

getting over PRUNING FEAR.... sure makes a pretty plant... dont you think ...

the real key here.. is that with NO ROOT INSULT... you are increasing the vigor of the new growth ... as it still has its mature intact root system.. and all that energy.. to put into fresh.. young.. vigorous growth ...

congrats...

ken