Friday, July 20, 2012

The evil Orange Daylily

Species name: Hemerocallis fulva

Common name: Orange daylily, tawny daylily, Tiger Lily (although this common name is misapplied)

Location: Ontario

Up until now, I've been profiling daylilies that are cultivars of the same species, Hemerocallis fulva. There are some cultivars that have been back-crossed with another species, but this is relatively rare. This one species of plant already contains all of the genetic variation (plant size, shape, flower size, colour, etc.) needed to produce all of the daylilies we've already seen. Also up until now, none of the previous cultivars profiled have the ability to successfully reproduce from seed (at least, quite rarely) and don't produce extensive rhizome systems underground so have a relatively small chance of becoming invasive.

This species of daylily, the one from which most modern cultivars are derived, is one of the most invasive plants in disturbed areas in the northern half of North America. Unfortunately, a lot of people seem to be under the impression that they're native to this area, and actively propagate this plant in roadside ditches and meadow areas. It's unfortunate when an invasive species is so visually appealing to so many people! The other unfortunate part about this plant is its success at reproduction; unlike many modern cultivars of daylily, this species is incredibly successful at reproducing sexually from seed. It can also successfully reproduce asexually from rhizomes (for example, spreading along the fence in clumps as illustrated in my back yard) and from re-colonization from broken colonies. If you dig a clump of tawny daylily out of the ground, make sure you ensure there's no contact between the roots and the soil below the clump or else it will re-root itself before you can even blink. Fascinating, but not if you like that part of your garden (or lawn!) daylily-free. The tawny daylily is also an excellent competitor for resources with other herbaceous plants in the vicinity, so it will also completely wipe out plant diversity in the area in which you're growing it. Even other "weedy" species have no chance against this plant.

The tawny daylily can also be eaten, but there seems to be a significant difference in taste between this species and the one most commonly used as "golden needles," Hemerocallis lilioasphodelus.