I have had better luck saving seed from the perennial alyssum, but the principle is the same. The seeds are teeny flat disks that line the stem where the flowers were. The disks ripen and fall out leaving the little round frames where they once sat. It's one seed per frame I think.

Does that make sense? The trick is trying to shake them off when they are ripe before they fall off. The good news is that the annuals seem to self sow nicely and I got repeat performers cropping up here and there near the spot they were originally planted.

This is a good question - perhaps I will stroll out there tomorrow night and see what's shakin. The other good news is that germination is quite high and they really winter sow well, so several dozen should get you a nice crop.

Good luck.

"The trick is trying to shake them off when they are ripe before they fall off."

I figured that was what was going on! It seems like the seeds (or what I had assumed was the seeds) are going from green to gone. I think I will figure out something to put beneath them to catch the seeds and see if that will help. I really appreciate the info!

Great idea on the catch-basket! I will try that too, thanks.

If you look beneath a perennial alyssum, there are scads and scads of dropped seeds. When you touch them, they just drop like confetti.

I checked my alyssum this afternoon and it seems it's going to be a little more elusive to gather seeds from the annual. Looks like it's going to be a labor of love for you guys. Go for it.

I pull them up and turn them upside down and catch the seeds - they're like dust.