The "white mold" and curling leaves you see look like powdery mildew, which is a fungal type infection roses can suffer from. Its usually linked to temperature or bad airflow; spring and late autumn are when the temperature is just right for PM to flourish, but some varieties of roses are just more susceptible than others.

I dont grow any drift roses myself, but according to the comments on Help Me Find Roses, some of the drift varieties do seem to suffer a bit from mildew..

While PM usually isnt enough to actually kill a rose, it can be made pretty unhappy; the yellow leaves may be a sign the plant is dropping any older leaves so it can conserve energy to deal with the attack ( looks like you have a few buds that may be about to drop off/abort too).

Not sure where in the world you live, but just going on what I am familiar with-

It looks like you have a few other plants in the near vicinity- how much air circulation is there? how many hours direct sunlight do the roses get? Just asking because it looks like one rose is right next to a very healthy looking hydrangea- in my yard, hydrangeas tend to fry and dry out with the amount of sun roses would need...

Also looks like you have some larger type trees behind- could their root systems be interfering with the rose?

Great comments by Curdle. I am also guessing that they are undergoing transplant shock. I've found it's hard to overwater newly planted bushes if there's good drainage. PM likes hot and dry conditions; spraying the leaves with water may help. Diluted skim milk can also work. My red drift came with PM as a Lowe's sale plant, but recuperated and is super healthy this year. I would think the evergreens are consuming a lot of water. Perhaps some mulch could help conserve moisture around their base.

Thenk you both! My gardener was here today and believes I planted one of them too low into the soil and fixed it for me. He thinks the drifts problem is not enough water, so... I watered well and fingers crossed