Good to see some Hudson Valley people coming out of hibernation. The gold and house finches are back at my feeders, the golds beginning to get a bit more gold.
I do landscape gardening as a profession. We cut back practically everything in the fall (so we dont have to do it in spring and of course, the woody shrubs just get a trim) Yes, cut back the Eupatorium to 6" or so. They will sometimes self-seed but the young plants dont seem to be as "chocolate"

Great, thanks for the info. I'll be on the lookout for any little seedlings - I was wondering if the seeds came true or if this was a plant more often propogated by cuttings.

Mine dies back to the ground like any perennial so I just cut it all the way back. And yes, it does self-sow but I noticed that the seedling I got did not have as dark foliage and expect more seedlings would exhibit a range all the way from milk chocolate to green.

Mine also dies back to the ground. I had my first seedlings last summer and they were the same color as the main plant. I didn't move them so I'll see what happens when they come back up.