I just bought 5 of your goldmound spirea (3 gallon size) plants. Since it is almost the end of the season, the plants are a little beat up with portions of the foliage/branches either dried or bare. I have just planted them in the ground. Should I prune back the branches that appear dried now, or should I wait for early spring? The plants are about a foot tall, how much should I prune them? just the dried portions, or should I drastically cut them back to the ground?