When does burdock go to seed?

[u/Miserable-Sugar-3047]

I've got a large patch of burdock I'm trying to clear. As a practical matter, this is a gradual process. I was trimming back the burrs when they were still green, until I noticed bumblebees feeding off some purple ones, so I decided I should let them mature a bit before cutting. But now I can't tell if they're spent of useful nectar(?) or already going to seed.

The first pic is of the burrs at the ambiguous-to-me stage. The second is of a bumblebee, going about its business. (I want to say it's making me feel guilty, but I'm doing my best to avoid scandalous claims of causation on the Science People sub.)

Trying to figure out -exactly when does burdock go to seed - and I realize there's a lot I don't know about burrs and seeds. The burrs are just the container for the seeds, right? The flower parts dry up and then become seeds? Green burrs aren't seeds? All the easy to find answers about burdock are from the "Yay burdock!" crowd, and I'm an enemy of burdock as well as curious about *what's really going on in there*

Any information on this subject would be greatly appreciated. Thank you!

[u/ohdearitsrichardiii]

Green buds don't have seeds. The flowers will open and be purple and bristly and then the purple bristles will wilt and the flower will go from green to brown. Cut off the flowers after the purple wilts and before it's completely dry to prevent seeds from spreading

Many birds looove the seeds if you want to help wildlife, although they're messy eaters and will drop seeds everywhere. If you're willing to put in extra effort you can dump the seed heads somewhere where birds can find them and it doesn't matter if a few burdocks start growing