The tallest plants against the wall and to the left. They kinda look like tumbleweeds when they're young and short.
They grow most of their seeds up on the top and on the ends of "branches" but the seeds are soft until the very end of the season, and even then they're never stickers.
Here's a closeup of the top of one. I chose this one because the stem is striped purply like young tumbleweeds. I don't think they're related (or not closely, at least).
They can grow to be six feet tall or more if they get enough water, but some are grown and done at two feet tall. That's kinda how desert plants go. These break off at the end of the season too, and if they were round they could roll, but they have the shape of Christmas trees.
When they're young, like this one, horses will eat them. They're not harvested and fed to horses, but kids will feed them to horses and if horses are where those weeds are, they'll eat the tops. We had an apple orchard when I was a kid, and I think it would've been full of those if not for Kate our horse.