I have never had these pests before, nor have I ever seen them. I've searched several websites for clues & the best guess I can make are wooly aphids? I'm only familiar with regular green aphids commonly found on roses & such. It's not mealybugs (worked interior plantscaping for years, familiar with those buggers) These bugs move fast, unlike mealybugs & are shaped different.

When I first found them, tiny green bugs would hop from the cottony substance when touched. Wondering if those might be a different insect? Haven't seen much of those anymore & was thinking it's two different insects.

I don't know, but these fluffy white insects are suddenly wreaking havoc with perennials & have now moved to several different perennial beds & are now on young hydrangeas. They completely ate the new growth off many tall garden phlox in no time. Don't want to hurt beneficials & have been knocking them off with strong water spray until I know what to do with them. I'm in middle TN near Nashville. Any help is greatly appreciated!

(the pic is on a young 'Incrediball' hydrangea)