My neighbor had some growing and she was cutting it down for the year. I
got 2 branches of the plant, planted them and they grew to monsters! They
put our beautiful sunflower like flowers. To use it, just chop some down,
and dig out some of the root, as much as you need - it will regrow. About
finding them in grocery stores, that is rare. But look where they keep the
parsnips, rutabagas, garlic, etc. and you can plant that root.
Right now I have to go out and dig up some thai ginger!

--
gloria - only the iguanas know for sure