OMG hi Verena, welcome back!! I had a mass planting of tall cosmos this year, it got about 6' high so if you need something big it was really nice. Didn't bloom until later in the season though.

Other self-seeders for me have been poppies and nigella. Careful what you wish for though, some of these seedy annuals get into everything.

Have you thought of seeding perennials as well as annuals? Of course the first year they likely won't do much altho some will flower their first year. I've found lamb's ears, feverfew, and shasta daisies are very good at self-seeding and may flower the first year. They are also good plants for bees and butterflies.

In an attempt to have an easier garden to manage I seeded several flowering perennials this fall. I collected seeds from my peony poppies, Oriental poppies, Blue Fortune Hyssop, columbine, and flax and just broadcast them over a rough area at the edge of my garden. Not sure how much will grow as the soil isn't great but in the spring I might spread a bit of compost lightly. I plan to do this in several areas and will buy some annual and perennial seed in the spring and sow more.

I will have to try cosmos, I had a few in one of my large pots on the patio this year and was impressed and they are listed as a plant deer aren't partial to which is a real plus.

Thanks for the ideas. I had cosmos at our old place and really liked them. Don't know why I didn't think of flax either for that matter...it's DH's favorite and always does such a nice continuous show.
I sowed a row of poppies (purple singles/red singles, and pink peony style) in the garden two years ago, and they came up very nicely this summer, in my peas. We left them because they just looked so nice. I collected about 3 LB of seed off them this fall and saved it to plant next year. I'm going to get the pigs to till me a 4' wide strip along the front of our yard site (about 500 yards) and plant it with the poppies. (Hoping that the authorities aren't going to think I'm going into the opium trade... :oP)
I'm looking at doing a mass planting of echinacea purpurea, and that might go well with the hyssop since both grow wild here. Still undecided if I want to go mixed or do color blocking. Hmmmm...

I forgot about flax, I planted scarlet flax this year and it was nice but I thought the bloom was a bit sparse compared to the blue kind. Guess I'm stuck with it now anyway. ;0)

Verena,

What about buying or getting some daylily seed? You wouldn't be sure though of what the color or size they would end up being but, it would be cheaper than buying the daylily plants. It will take at least 2 years for them to bloom but would be great foliage in the bed in the meantime.

Brenda