White Swan Compact White Mophead Hydrangea. I found this cultivar some years ago at Louisiana Nursery and we really like it. The inflorescence is slightly larger than 'Mme. E. Mouillere' with the individual florets being larger as well. The foliage is a much darker and glossier green and I think it will be more compact in habit. If pruning is needed, do it immediately after flowering as the plant will have time to put on new growth that will set flower buds for the following spring. So that flowering is not affected, try to prune at or before early August.