Maybe selecting varieties that are not suited to your zone would reduce the number of volunteers? Maybe just try random different cultivars of any plants that currently reseed too much, hoping to stumble onto something that doesn't like your climate as much as its cousins do.

Fancy hybrids might drop fewer fertile seeds, or at least less-vigorous seeds.

It seems like a balancing act: well-adapted enough to thrive and flower, but not set a lot of seeds.

Or maybe there is some variation in methods that would discourage seed germination: coarse mulch while seeds are dropping? Surface cultivation after seeds tend to germinate? Time your additions of things like compost or mulch to go down right when new seedlings are most vulnerable to being smothered?

If they're not suited to my zone, the mother plant will croak

Karen

I should have said "marginally suited", so that the number of reseeding sprouts was reduced.

For example, a plant with seedlings that need more rain than you usually get in that season, but where the adult tolerates that becuase it is established.

Or one that is on the tender side for your zone, so that an adult is OK, but seedlings find it a bit cold and sprout too late or can't compete.

Karen: How about some of the hybrid echinaceas? I've had several that haven't reseeded at all. Some suggestions: Coconut Lime, double pink, Milkshake or Meringue (sp?) These have all done really well in my garden for a few years without throwing seeds/seedlings. I've also had bottle gentian for a few years without reseeding, as well as aconitum (monkshood). Turtlehead (chelone) don't seem to spread agressively, either.

I love turtlehead.. I have some living in a container for years now.. really should toss some of those seeds out in the garden

I've not tried turtlehead.

I think I have too many coneflowers! Lots of regular purple, and last year wintersowed White Swan. I also have Pink Double Delight, Hot Papaya, and this year bought Hot Summer and Milkshake.
Coneflowers everywhere!






Karen

hope your PDD is better than mine.. it's a flopper here

My PDD does well. It's a smaller coneflower, I don't think it gets much taller than about 2'. Flowers are pretty and dainty and the plant never flops.

This was last year


Karen