As it's a grass, it grows from the bottom of the plant, instad of the yop like other flowering plants, so the more you cut it (up to a limit, of course) the more you'll encourage it to grow. I cant remember the percentage of alkaloids, but if you get a kilo of the stuff, even 0.5 percent alkaloids will net you 5g of the DMT/5-methoxyDMT mixture.
As it's not a woody bark (so easier for a solvent to penetrate), I'd imagine a simple solvent like alcohol should extract the majority of the alkaloids present (but a lot of chlorophyll as well), but this can always be processed further once you reach that stage