It spreads through rhizomes. I have not grown it but what I do to keep spreading plants in checks is to either grow something next to it that is also a spreader or pull up/dig out around the edges.

I've been meaning to get back here to give you some info, but haven't been feeling too good--and I know you know what I'm talking about! (Am finally feeling better, BTW!)

Plumbago, Ceratostigma plumbaginoides, is BEYOND a thug in my opinion! As GJCore said, it spreads by underground rhizomes, and it goes far and wide once it's had time to settle in! This is one of the things, when I was at Paulino's, that would be sitting in the growing field in gallon pots, and it would be growing out of the holes in the bottoms of the pots and into the soil beneath the pots! I don't buy anything that can/will send rhizomes out of the holes in the bottom of pots--even small pots! That's a STOP sign for me! I made the mistake once when I put in some Zauschneria I got a a swap--because I think the stuff is really pretty when it's blooming, and it took me a couple years to "correct" my mistake, and I'm not planning to make that mistake again--no matter how pretty I think something is! And Plumbago can be really pretty, especially in fall when the leaves turn red and you can still have the blue flowers at the same time! But it's just not worth the time it takes to "delete" things like that after the fact, so I'm not gong there anymore!

If you have a "large" property and can plant it in the "outback" somewhere, I'd say go for it, but if you leave it where it is, in a couple more years it's going to completely take over everything in that picture--and more. You just need to decide what you want in that area in a couple years, and if it's more than just the Plumbago, I'd say start getting rid of it now.

I know that's not the answer you want! Sorry 'bout that!

Skybird

P.S. If you decide to move it someplace else, keep in mind that it WILL go under fences into neighbor's yards.

Thanks to both of you. I'll have to decide whether I want to get rid of it entirely or just keep pulling it out where it goes beyond where I'm willing to tolerate it. I'm not sure at this point. I was at my favorite garden center today (and am about $130 poorer - but to be fair, $60 of it was for a birdhouse) and the expert there whom I've known forever advised me just to pull it out where I don't want it. It's hard to believe that it took it something like 8 years to get "happy!" If I do pull it out I'll have to decide what to replace it with.

BTW, Skybird, I have two large patches of Zauschneria on my back dry slope, and it is indeed spreading. But since I do need ground over there, it has plenty of room to spread and I thoroughly enjoy the fall color. It tends to get tangled up with my winecups (Callihroe involucrata), and they compliment each other. Especially when the Oenethera gets in the mix! Glad you're feeling better - it's about time!

Kat