I have read several posts this year of Pee Gees with a little dieback at the ends of stems so vagaries of weather may be causing the problems. Paniculatas are not the most drought tolerant hydrangeas (oakleaf hydrangeas somehow got that rating). If their soil gets dry now, the leaves will brown out from the leaf edges inwards and the stem or parts could dry out. If the soil in winter is both dry and unseasonably cold, there could be dieback near the ends of the stems. While they are winter hardy to Zone 3, they are not immune to weather issues in some years.

Your local weather in prior years may have provided enough moisture but 2018 monthly totals in Toronto at least are so far lower than 2017. Thus, I would not worry unless the dieback is 1/4 or more. That is when my eyebrows would start wow-ing and moving all over!!!

thanks.. I am going to take a pic.. it's almost like they are wilting.. really weak stems...

Personally, I'd like to see a photo before drawing any conclusions :-) It may be that the cause is entirely separate from any climate issues. And IME, paniculatas do tend to be more drought tolerant than most species, the exception being the oakleafs.

we have had a lot of wind... the last 36 hours... heavy nw winds as a cold front swept through... going to take the pics soon

luid_pr, all other plants are fine... the dry spell continues.. south of us they got heavy thunderstorms with that front, but we are sunny and upper 70s today and 90s on the weekend

It is really difficult to figure out plant health issues without photos. Can you please add some.

here you go...

First pic is the Limelight...

You will always have a few stems that for whatever reason lack vigor. However, the vast majority look just fine and will produce great flowers.

its also possible that the wood in those areas that have defective flowering stems has gotten diseased. it happens commonly. If you want you can cut the wood to check if it’s diseased. If it is diseased. keep cutting back till you hit healthy wood.

I agree that it’s best to cut out the damaged stems since the rest of the plant looks fine. Sterilize the clippers between cuts with a bleach solution or wiping with alcohol. It looks like either disease or damage from something like severe winds or a chewing critter may have caused damage, so I would likely spend some time looking at the lower stems to see if there is evidence of borers or fungus or gnaw marks. I might also push down gently on the surrounding soil to see if there is evidence of burrowing critters that might have damaged roots.

I have never seen this type of problem in panicled hydrangeas. How long have yours been in your garden?

the limelight 3 the other 2.5

So it’s definitely not something that originated from nursery culture.

Ok just by chance could it a animal ( cat/dog ) running through breaking the stems... I have had that happen to me

sure hope it's not! anyhow i will deeply water and remove damage and see what happens.. thanks to all... btw, i saw a vole in my grass... i know they can do damage...