Aralia racemosa American Spikenard (among many other common names) is (potentially/over time) an imposing plant! With the stature of a medium sized shrub as it grows and depending on the site, this is actually an herbaceous plant dying to the ground every autumn.

I grew mine from wild Ontario seed, and they flower rather late for this Alberta climate- for the first few years they didn't ripen fruit, but they've managed it more recently. The flowers must have some powerful scent that attracts pollinators- I've seen bees, various flies including flower flies and above all- wasps of all sorts, both the common sorts such as Yellowjackets and Bald-faced Hornets (actually wasps) and the less numerous more exotic sorts like Ichneumonids (those wild looking critters with looong ovipositors that look like deadly stingers, but aren't!) Remember wasps aren't just patio pests, they are very active and important in the ecosystem- scavengers cleaning up decaying plant and animal material, predators keeping other insect populations in check and pollinators- Yellowjackets esp are regular visitors of many sorts of flowers.