I was reading some about growing valerian and I think I get the idea but I want to ask anyway: How can I grow the plant to get the largest and easiest to harvest root mass? Like should I leave a large rock in the middle of the pot near the top so the roots grow over it like how some people do with bonsais? The info I've read on it so far seem to imply
>grow it like a regular plant in ground or potted
>before the next spring, dig up the plant
>cut back the roots, dry
I imagine doing it this way would take a very long time to get a harvest worthwhile, am I wrong? Thank you