They are hussies! Hollyhocks are another plant that can't keep its knees together either ;-O

It's going to require an, ehem, prophylactic covering. EGAD! I found a Ken Druse NY Times Garden Notebook article that describes but doesn't detail the method.

Here is a link that might be useful: Wildflowers: The Mating Game

Thanks Trudi! I wonder if you can get those"isolation bags" from a gas station bathroom :^O
I already fell a little bit dirty!!LOL!!
-B

LOL.
Here's an article about making hybrid clematis which shows how he just used a plastic ziploc baggie and cotton wool.

But since you are trying to prevent cross-pollination, maybe the simplest way would be to grow some of them all by itself in a fairly isolated spots so that those would self-pollinate?

Seeds from these hybrid Echinaceas won't come true either, right?

I've heard of each plant being wrapped in row covers to keep them separate. I think you have to take a q-tip to them in order to help them pollinate.

I love the way this thread is going, lol. I never thought of it that way before. I hear that columbines are quite wanton too. I've never had more than one kind so I'll find out after this WS.

Here's some more info on the coneflower hussies
-B

Here is a link that might be useful: seed saving forum