In article , "Vox Humana"
wrote:

I got several of these plants last year from Bluestone Perennials. They are
not listed in the catalog this year, so I thought that I would divide the
ones that I have. Despite our unusually cold winter, they came back with
vigor

Though semi-tropical in origin, that deep root means it is hard to kill
even in cold zones. Here in Zone 8, it's semi-evergreen.

so I dug and divided them. I noticed that they had a substantial tap
root. Did I doom the plants by cutting them in half?

They self-seed so easily they can become weedy, so there oughtn't be a
need to attempt division, there'll be plenty of seedlings eventually. I
have for the last three years deadheaded mine to keep it short & fluffy,
but might this year let it go to seed, though that means letting it get a
bit rangy & tall.

Sometimes they have two joined but distinct roots & of course those divide
with no problem. I wouldn't personally risk intentionally breaking a
single main root, even though in fact many broadleafed deep-rooting plants
of this sort can regenerate even from a root fragment. Rumex species CAN
have their root divided longitudinally & recover both halves, but I don't
know to what percent of successes, & it wouldn't be my choice to try it.

-paghat the ratgirl

--
"Of what are you afraid, my child?" inquired the kindly teacher.
"Oh, sir! The flowers, they are wild," replied the timid creature.
-from Peter Newell's "Wild Flowers"
See the Garden of Paghat the Ratgirl: http://www.paghat.com/