For various reasons, I have moved roses at different times of the year. The main difference is that if you move them in warmer weather, they might take a lot longer to settle in and you may have to water them a lot to keep them going for a while. Moving them in cool, even cold weather, is a lot easier.

The main thing is to water the rose well and then dig down deep and keep as much of the root ball as possible. Have the other hole all prepped and ready for planting before you dig up the rose. If you are lucky enough to dig up a big rootball, rush over to the hole and plant as quickly as possible and then water, water, water--really soak it in. I mean like, flood it. (Not so much water after that, however.)

You might want to prune back the rose by about 1/3--easier for you to handle, plus the newly planted rose needs to concentrate on settling in and growing new roots.

Do not feed or spray the newly transplanted rose. Wait until it has lots of good healthy growth--maybe a month, or even longer.

Once that rose is growing again, invest in a good fungicide and a sprayer. I recommend Bayer Advanced Garden Disease Control for Roses and Flowers (but not the other Bayer products) available at Lowes or online. The fungicide will help you with the blackspot. Even in full sun, some roses will still get BS.

Hope that helps.

Kate

If you're going to spray, be sure to read the chemical safety sheets on the material you use. (You can find those on line.)
And be sure to invest in a respirator mask, chemical gloves, and at the very least wear long sleeves and long pants.
This is Tebuconazole, which per Wikipedia is:
a triazole fungicide, listed as a possible carcinogen in the U.S. EPA Office of Pesticide Programs (OPP). Other entries mention reproductive effects.

And Kate is right. I'd almost bet money You'll probably have to spray these two roses, to keep them blackspot-free, even if you move them.

Jeri

Jeri's right about checking on the chemicals---search on MSDS and the chemical name. (MSDS is "Material Safety Data Sheet"--companies are required by law to provide them.)

Even doing as stated above, your bush will probably go into a funk and wilt before it revives, unless you can avoid losing soil from the roots. As soil falls away the tiny feeder roots fall away with it. Without feeder roots the bush has no way to take up moisture. This is what causes transplant stress. The roots you see when the soil falls away are anchor roots. The root ball can only easily support a like size amount of top growth and until the feeder roots grow back the top will be stressed.
Personally I'd cut the top back by 2/3. It'll grow back quickly while not stressing the bush so much. You'll lose some blooms this year but your bush should be back to normal by next season.
I suspect transplanting it to avoid blackspot will not succeed. There are a number of factors that make it ripe for blackspot to begin. Unless you correct all of them including spraying a fungicide, it'll return although maybe not so bad in a dryer location.