Hi, I'm not sure which artemesia silver mound is, but my guess is you can cut it back in half without hurting it for next year. Tracy disabo Aust talks about the various artemisais in her 1st book. She seems to prune for shape until mid July and warns againt cutting into wood and pruning in August. You're almost there but it might be worth a try on some as an experiment. I really recommend her book as a guide to maintenance pruning for lankier perennials.

You can cut Silver Mound (Artemesia schmidtiana) all the way back to the soil level now. If there is short new growth under all the lanky foliage...just cut back to the spanking-new dense growth.

Agree with Karen...that book is a wonderful reference. (The Well Tended Perennial Garden)
Jan

I agree- you can cut it back whenever it looks unsightly- if yours is are established plants that is- The only time I have had problems with mine was when I split it too late in the season-
Thanks also for the reccomendaton of the book-
Julie