Transplanting should be done when the plant is as close to dormant as they will get in your zone. Of course, rules are meant to be broken. If your plants are in severe stress because of the sun exposure that they now get then, by all means, scoop as big of a root ball as you can and move them now. Otherwise, wait.

Be aware that they will require monitoring for about a year. By monitoring, I mean watering multiple times a week during the summer (cut back when the temps go down in the Fall).
And, this isjust my suggestion, for the first month or so, do not fertilize. I would use Liquid Seaweed or Liquid Fish Fertilizer instead. Root stimulators would be OK as well.

See the link below for more information and good luck!
Luis

Here is a link that might be useful: Transplanting Hydrangeas

Hi mboston,

You said the plants are large....how large? If you are able to move the whole plant, do it but not now. They have lived there for this long, the rest of the summer won't do any more harm. (will it?) This is a hard time of year for established hydrangeas down here let alone transplants. While I have planted smaller hydrangeas in summer, the large established plant will have an extra hard time re-establishing in this awful heat.

You could move it in fall if you like but I have found February to be the most dormant time for the plant in this area. As you know, another flush of blooms may come in October/Nov or so and new buds will be set by Jan (?) It will be at it's most dormant (and least needy) state in Feb. Wait until after the frost date (usually around the 12th but with the whacky weather changes we've had lately, you might have to play it by ear)

Then follow Luis' instructions. Whatever you can do to amend the soil in the new planting hole would be better than dropping it in to the sand we have here. Black cow aged manure is great stuff. Dont' forget to give it plenty of water all through next season, it will make all the difference and there is no reason that you should not see blooms next season.

Good luck....yg

How about putting up a temporary sunshield like a tent just to protect the plants for the time being. I had a burned (new transplant) Nikko Blue last summer and all that I could do was to provide a sun screen. It worked and by the time the summer was over, the plant became very established in it's area.

Well, I have a dual purpose to moving them. I am running out of room for my butterfly garden and since the plants need more shade than where they are and the butterfly plants need full sun, it makes sense to switch but I hate to do anything to damamge the plants. Some of them have been around 10 years or so and have spread. Others are smaller and wouldn't be hard to move at all. I just hate seeing all the dried, fried blooms. I don't rremember getting an additional flush in the fall- maybe cause I usually quite feeding them around that time. Thanks for the info - I thought I should probably wait.

I have had a hydrangea in a pot for the last 3 years. It's done well in the pot, but is in a mostly shady area. I am hoping to put it in the ground, but the only area I have available with shade gets morning sun. I was always under the assumption that these needed shade and wouldn't grow well this far south. Will I be able to plant it here? If I am able to plant it in the ground, should I do so when it becomes dormant (as stated in the above post)?

Thanks,
Christie

I live in zone 5 , when is the best time for me to move?? If i wait till they go dormant it is already cold, will they root then??

I moved two of my endless summers this spring. I think it was early April, before the leaves started to bud. With everything that I read I think the best time to move them is before they start to open their leaves. If you can wait till spring I think you won't have any problems and much easier to handle the plant. Good Luck!

My sister is having an addition to her home and has to move her very old hydrangea (Annabelle, I think). And it has to be done now (mid-May).Besides a very big root ball and putting in shade, any other tips?