I’m not sure how hot it is where you are but as long as not too hot probably can move them. Just be aware that they will be quite vulnerable to heat stress / transplant shock so will require close monitoring.

guyground made me realize that I should've told you that we watered that shrub faithfully the rest of the summer after we moved it..also I have a wooded lot with dappled light and the temperatures are much cooler than a full sun location..

Generally I never move plants in the summer as from past experiences its always ended poorly. However, in Canada might be able to get away with it if temps not too hot. Generally speaking fall is best for transplanting as soil is warm, plenty of sun, and cooler temps.

I move hydrangeas all the time - just make sure they are kept nice and moist. You did not say how big it is - but if possible it would be a good idea to shade it for the first few day. You can use a chair, card table or umbrella. If the plant is real dry when you dig it up, soak it in a bucket of water for a few hours and then plant. Annabelle is really tough and should be just fine - it might even set broccoli this summer.

How warm does it get during your summers? Your climate may help with this move as it should not be too warm in the summer months but, be ready to check it during the warmest days. Do not plan to go on vacation unless someone can water it while you are gone.

In my terribly hot summers, I would not move a hydrangea once temperatures start to reach and exceed 85F/29C somewhat regularly in mid May. I also find arborescens to be more sensitive to lack of soil moisture problems as it is the only one that I have managed to kill during dry winters, Ooops!

Thanks to all. Our temps have not been very hot at all yet. We have had a cool and wet spring so it sounds like I can go ahead and move it. I will keep an eye on it as per everyone’s advice.

Temps aside, summers right around the corner. Why stress it...when you can do a fall transplant, unless it has to be moved immediate...