When we built our retirement home a few years ago, we surrounded the patio with pollinator plants, one of which was a mass of the native Eupatorium purpureum ‘Little Red’. For the last few weeks, we can sit in our screen porch and watch a steady parade of butterflies. This amazing perennial, which forms an 18″ wide basal clump, really thrives in a moist, rich soil. In 30 years of growing this exceptional clone, I don’t recall ever seeing a garden seedling.
My patch – originating at PDN about 20 yrs ago – does the same here.