No idea what zone you are in, but the best time to transplant anything is when it is as dormant as it gets, as long as you can still dig the soil.

Here, roses almost never go dormant, which makes transplanting them trickier, but we have done it successfully. No expert, but here is what we do:

1) Prepare the new hold where it is going to go first - I would dig a hole about 18 inches deep at least, and wide enough to accomodate the size of the rose you are digging up. I just mix in some planting soil - no extra fertilizer at this time. Make sure to mix the plating soil with the dirt, and make sure that the sides of the hole are roughed up, so that it does not form a bathtub. Have extra planting soil ready to use to add after the rose is planted in its new home.

2) Cut the rose back to maybe 2 feet from the ground - this is very important!

3) Dig a circle carefully all around it with a sharp shovel, 12 - 18 inches away from the base of the rose. Keep making the digging cut deeper until you have a reasonable chance of getting most of the root ball - 1 to 2 feet deep.

3) Then, my DH uses a heavy pry bar to lift one side of the root ball, so he can get the shovel underneath the rose. Keep prying and lifting, until you can get the root ball & the rose out of the dirt.

4) Immediately plant it in the new hole you have prepared. Water it in well.

5) Leave it alone, except make sure it gets enough water for the soil to remain moist - its roots have been damaged, and it will need extra water care. Then leave it alone, and do not be surprised if it just "sits there" for a while - it is growing new roots, which is an activity that is not visible from outside - do not panic if it takes a while to start putting out new growth. AFTER it starts putting out new growth is a good time to feed it.

The above works in my zone 9 climate, but if you are in a really cold zone you should get local advice from folks with experience transplanting roses in your area. Good luck!

Jackie

Thank you Jackie,
I'm in zone 9 FL. My soil is basically dirty sand despite the amendments I've used. I'll be attempting this in the late fall as most of the roses don't go to sleep until then.