I really want yellow butterfly bush, pussy willows and tall phlox (not purple)prefer orange or a mix of colors. I have 3 small rose of sharons to trade (small bush now) will have red raspberries in a few weeks and coneflower seeds in some of the fun colors white, green, etc). Or I would send postage to you. Have a wonderful spring....look out for toads...

I have a rooted white savolens brug to trade for a butterfly bush Kiddo

If you can wait a couple months, I have Attraction, Bi-Color, Black Night, Pink Delight, Royal Red, White Profussion, Nanho Purple, and Honeycomb. My butterfly bushes are still at ground level for the year. I cut them down every year. I wouldn't suggest Honeycomb for your zone though and you may have to check on the rest. I do not know which ones are hardy to zone 4, I just know Honeycomb is boarderline in my zone. I do not need any more butterfly bushes though and I have no idea how to make butterfly cush cuttings.

You composted already so don't fertilize anymore until you know what's going on. Sounds like it could be stressed. How dry (or wet) has it been where you are?