That's good to know. I was under the impression they can take drier soils - maybe I was thinking of another plant. The place I bought it from has it in display gardens and it is a monster -- something like 8 or 9 foot tall -- wonder if the conditions are optimal/moist there. But, if there's a chance it might get ratty I probably don't want it too close to the house in front of the utility pole.

My ratty one is in full day sun, cruddy clay, and we can go weeks without rain sometimes in the summer. SO... you conditions might be different.

What nevermore said - every seed will take root, which is fine if you have room. Once the flowers are pollinated, like most tall plants, the stems start to fall to the ground, so another crop of cup plants will grow that 7 to 8 feet away. I tell you this so that you don't plant it by a path or road. If you can give cup plant room, you will have the happiest bees around.

I had one for many years but I always cut it down before it set seed. Good way to manage it.

Agree with lisanti — don’t worry too much about siting it, since the seeds will decide where they want to be. I think I started with one about five years back — in a dry spot in mostly sun — and now there are four big clusters (not counting what I’ve pulled,) all in similar conditions.

I had mine up against the south side of our old house and it did well it was pretty cool, the leaves do hold water, the finches and smaller birds would drink from the cups. Where did you find yours, I’d love to get this again!

Got mine at a local nursery - doesn't ship.

Prairiemoon does carry it, they have bare roots in right now: https://www.prairiemoon.com/silphium-perfoliatum-cup-plant-prairie-moon-nursery.html

Thank you!

Many native plant nurseries carry it, especially those specializing in plants for pollinators.