Thank Lin for the link, with the blooms images..
In pots they can stay small (but usually never blooms), just make pups and dye.
On ground it can get around two meters tall here, then blooms, but also produce much pups.
It tends to not blooms if the leaves being cut often, but if not cut, they got too-big too-quick, that is why they were rarely seen blooming. Even when in bloom, it usually hidden by those large leaves, and the greenish color are bit inconspicuous. So they are usually grown for their leaves.