Can they be saved?

I picked up a couple of plants on clearance in a local big box DIY/garden center thinking I could maybe salvage them and see if they would come back for next year. One was a Veronica and the other a Dahlia maxi of some kind. The Dahlia looked bit worse for wear but am I right in thinking I can dig up the bare root and plant it next year?

Also, the Veronica while it had plenty of foliage had no flower stems so I thought it was just at the end of it's growth season. In the last week it did put up one bloom but it also has developed a whole lot of curly leaves and white powdery stuff which I assume is powdery mildew. If I cut it back now will it regrow next year?

Veronica

Dahlia

Jim_Hodge

I'd consider leaving the dahlia in the pot, let it dry out when withered and store in a frost free place until planting out in spring. The Veronica can be planted out now, kept well watered and cut back when it withers.

Thanks Jim