Also, if it doesn't grow back out, don't panic, but wait and see what happens in spring. As a zone 5 alba, it was due to drop its leaves in a few weeks anyway. It is better off not squandering nutrients to produce new leaves that will go to waste. (That's why this is the worst time of year to transplant.)

Hi Michael,
Thanks a lot for the quick replies. From what you say, I feel the problem might possibly be that I overwatered it after transplanting, or maybe didn't get big enough root ball. I got a big guy here to dig it up and he certainly got a broad root ball but not as deep as I'd hoped. I'll take your advice and sit tight. Re the weather, yes I'll certainly learn from experience next time. But we have come just a couple of degrees short of frost in our nights here in British Columbia, and there was cold drizzle when we moved it, but of course you have to take into account that in September the weather might warm up, which it did and I suppose that's why I watered it quite a lot. What a privilege to get to ask questions to people who know what they're doing!

Hi Michael,
Thanks a lot for the quick replies. From what you say, I feel the problem might possibly be that I overwatered it after transplanting, or maybe didn't get big enough root ball. I got a big guy here to dig it up and he certainly got a broad root ball but not as deep as I'd hoped. I'll take your advice and sit tight. Re the weather, yes I'll certainly learn from experience next time. But we have come just a couple of degrees short of frost in our nights here in British Columbia, and there was cold drizzle when we moved it, but of course you have to take into account that in September the weather might warm up, which it did and I suppose that's why I watered it quite a lot. What a privilege to get to ask questions to people who know what they're doing!

I wouldn't take off any of the leaves it still has. Let them feed the plant while they still can. They will fall off on their own eventually. They also provide some shade for the canes if the sun is still hot. Just keep it watered as needed and let it be until next spring.

After learning where you live, I understand that heat was not a factor, but roses just don't transplant easily unless from small or medium pots. When you dig them, the fine roots are lost or disconnected from the soil, and the coarse roots are not able to supply enough water. So they will wilt and maybe defoliate, even in mild BC weather, because lots of water is being lost through the leaves. The particular problem with transplanting this time of year is that any new leaves that grow out will not have time to replace the energy spent in growing them out. If you waited till late October, your alba (or other deciduous rose) would have withdrawn and stored nutrients from the leaves and there would be no loss of water from the foliage. Dormant roses can be transplanted without much pruning.

As to excess watering, soil being saturated for two weeks will kill the feeder roots and cause yellowing and defoliation. Soak the transplant in with a very heavy watering, let drain, and then water normally.

So overwatering may have caused defoliation, but it can happen without that.