Answer: The usual time to prune this shrub is in the late winter or early spring so all in all the deer have not done such a terrible thing by eating them in mid October. You could tidy away some of the longest growth now to try to bring the plant into visual balance for the winter view.
This shrub (Physocarpus opulifolius) tends to be a bit unkempt and scraggly looking in its natural growth habit anyway. You may want to prune it for shape early each spring by removing some of the oldest branches by cutting them off at the base. (This will probably not be bnecessary for a newly purchased plant.) This annual pruning regime will tidy the plant a bit and also keep encouraging new growth from the base.
An alternative maintenance pruning method is to simply cut the entire plant off short near the base in late winter or early spring. This more extreme treatment would be done as needed, probably just once every few years. I In any case, prune in very early spring as needed.
Routine fall care for newly planted shrubs would consist of applying a layer of natural mulch several inches thick over the root zone but not touching the stems or trunk and also making sure that the soil is kept evenly moist but not sopping wet until it freezes. To see if you need to water, dig down a bit and check with your fingers.
If the plants are in a very windy location you might also erect a wind break for them, but if the plants are hardy in your area they should not need extra measures.
Q&A Library Searching Tips