Hi, Judy >It has thick, substantial roots >covered with rough "bark." I don't know what to call them - some kind of >tuber? and not too much water. Scandant in >growth, the lax stems are equally happy when they can scramble up an >adjacent shrub or simply sprawl on the ground. I also grow Mirabilis longiflora, in western Oregon, wet winters but Z7. It is a sprawler. Moved to a dry spot where it didn't get summer water, it didn't survive. I should try again, it surely should thrive in dry summers. Both Mirabilis jalapa and M. multiflora thrive in the same area it now occupies. I seldom get to that area after dark, so haven't noticed fragrance, which is something I'm interested in. I've tried a couple times to hybridize these three species, but failed, primarily because it is hard to keep track of which flowers were pollenated. The seeds also drop easily if you don't watch closely. "Tuberous roots" comes about as close as I am able to name the storage organs of these plants. None of these species has thrived for many years in containers here, eventually dying out-though they may replace themselves from seed. Mirabilis longiflora ought to be nice in a very large planter, where it could sprawl to its heart's content. Mirabilis jalapa can be dug and stored like a dahlia, though I never bother, since it survives the winter in the wet ground. Digging Mirabilis longiflora might be a challenge. Ken