It appears to have been renamed. I did a brief search and it seems to be available at the 'Digging Dog' nursery in California.

Here is a link that might be useful: rename

This post was edited by lucille on Mon, Mar 4, 13 at 12:48

And here is another link which answers your question:

Here is a link that might be useful: Noxious plants

Ah! Thank you for that info. As a new ponder and a fairly new gardener, names, cultivars, genuses, species. . . . can all be very daunting, confusing and frustrating. I don't want to plant species known to be invasive or harmful to the environment although plants I have such as Sweet Breath of Spring, Nandina, Parrots Feather, etc. are listed as pests and invasive on the state listings. sigh. But I will plant and enjoy these seeds and pull them up when they get out of hand. And, if they threaten to take over, I will take drastic measures.

I feel as if a state has put a particular plant on a list saying it is a pest, that is one thing. Once they actually prohibit it, that is another.
I would not knowingly grow a prohibited plant. Not only is it irresponsible, and harmful to other people and many times to their work and property to do so, the fines are enormous.

I agree. I try not to plant things that are known to be invasive and, even if, in our Upstate gardens, will perish as an annual over winter, might survive and get into the waterway and live as a perennial in the lower part of the state. Luckily, this plant is not on the noxious weed listing by either name in South Carolina. I find a lot of marginal plants that are recommended in magazines and books, such as this one and Rodgersia, for example, are very hard or impossible to find in my area. I appreciate the links you provided. Thank you very much.

It's a European plant that has found its way into a few botanical collections in the US and that's about it.

Perhaps those botanical gardens have plant sales...

I can see why pond folk might not be inclined to try it, it's a long lanky plant, non descript foliage, hardly likely to fit in a pot for long, its flowers a bit mundane compared to others, likely to sprawl and smother wherever it romps

The polygnums do have a history of being rampant and weedy...

So far, I don't think my seeds have sprouted although others I ordered have. So, just now, it's undetermined whether I will have plants to add to my pond side collection! I apprecaite the information although it does concern me that it may 'smother' other things.