If there are still seeds on the plants it is definitely not too late. You will have to trudge back there to look close to be able to see if the seeds have dropped out or not. Like many annuals, they self sow easily so if you didn't deadhead them you may have lots of plants volunteering in that spot in spring with no need to sow them at all. You could also sprinkle the seed on the ground and work them into the top layer of soil with a trowel after the snow melts when you clean out the garden.

I would think that the birds have eaten any mature seeds by now. The Goldfinches love the Tithonia and Zinnia seeds, and whatever seeds I don't collect they seem to eat them in the fall. Might be worth checking them out though.

I collected seed from my grandmother's garden back in late November when it was really cold and there was snow on the ground. I wasn't sure about it either , so I germination tested them when I got home and they grew just fine. Hope that helps. : )

I'd go out and snip off any flower heads left and bring them in to look for any seed left. If no seed, just toss in the garbage. If there are seeds, place them on a plate or paper towel to dry for a few weeks. At least in my area, I need to get Tithonia started early, if I want blooms before frost. So, I wintersow them in the warmest, most protected part of my yard and transplant as soon as risk of frost is done.

Martha

Thanks for the input. I trudged out today and got 3 or 4 seed heads. They all look like they have seed in tact. The rest are buried under snow. I've never had tithonia self sow. I'd be thrilled if I did.