If you want as long a flowering period from your cosmos as possible then I would dead head them Lukey.
I've been doing both. Dead heading to help promote more blooms (not to mention seed gathering) but also leaving alot to self sow.
how come you never do it carolyn? i think I will leave some to seed but not just yet. I want to enjoy the flowers
A serious lack of time. they just tend to reseed themselves, I never plant new ones, just wait on the seeds to restart and grow. I am far busier in the veg. garden than the flowerbeds, but this year maybe I'll have more time in them since kevin put drip irrigation in the garden and we are growing more veg. in less area with the high tunnels. This is the first year in the last 4 that I actually have flower beds. I have used them for veg. beds to support the growing needs of the farmers markets I attend. I planted most of them with flowers this year so I actually have flowerbeds now. Yesterday I planted the serrano peppers and a few ground cherries in the one bed along with my marigolds. which turned out to be a very good idea after the rain in the afternoon washed out most of the soil where i had room left to plant anything more.
