Hi Yardgirl:
I got a few cuttings of gooseneck from a friend a few years ago and I planted them in my front border. Strangely enough, they multiplied very slowly and only this year are a sizeable clump and in full bloom. I believe many people confuse the name loosestrife, with the wild purple one. BTW, there is also a cultivated purple one which is not at all invasive. So go ahead, they make great cut flowers and you can always rip out what you don't want. I don't think these ones will 'walk'.
Northerner.

My experience with gooseneck loosestrife is fairly limited; however, I planted it about 4 years ago for the purpose of having a taller groundcover. It's in an area that is very shady but stays moist thru out the summer. It has spread throughout that area and sneaks out a few plants out of bounds in the spring of each year which are relatively easy to pull out. I haven't found it to be troublesome yet. I think if it was going to be I would know by now!

Thanks, Northerner and Magpie.

I was pretty confident that I had thought things out, but I've learned to check GardenWeb! Magpie's experience is especially cheering: yes, after four years, the mistakes usually come out!

Yard Girl