The basic orangish common-as-dirt form of the daylily is Hemerocallis fulva. The various cultivars mostly have some level of hybridization in their ancestry, but generally have some amount of Hemerocallis fulva in them. In general, cultivars tend to be less vigorous than the real thing, but that doesn't mean some of these cultivars can't become invasive.

Patrick Alexander

Yes, they are the same thing. There are many colored & patterned varieties of day lilies but the wild ones you see on the roadsides around here are the Hemerocallis fulva that have escaped from gardens. I guess they could be considered invasive if they pop up somewhere you don't want them to. There are also Canada, Carolina, and Michigan lilies that have that distinctive orange coloring but they are more rare.

Thank you Patrick Alexander and mrsmusic!

The "invasive" types are the wild/orange ones not commonly sold in garden centers. The hybrids as per invasiveness etc. are fairly different. You can plant them in your garden with NO worry. Also though the orange daylilies while somewhat invasive never prove terribly so. And I have seen them growing in various places like woods.... a few here a few there. They don't look likely to cause some major problem. :)

Thanks flowersandthings. I'll probably avoid getting any more daylilies than I have, just to play it safe.

Lori

H. fulva is a sterile triploid. Since the plants rarely if ever produce seed it spreads solely by spreading rhizomes. The plants triploid nature makes it a dead end genetically and it is not a parent in modern daylily hybrids.

The invasive nature of this plant is much over rated when compared to other invasive plants that are capable of sexual reproduction. Most 'invasive' populations a remnant and negleted planting.

Thanks happyhoe. -- Lori

I would not worry about daylillies being invassive, they are not aggressive and in the time I spent typing this follow up I could have destroyed a fairly large patch if I chose to eliminate them.
Just because a plant is not native does not mean that I have no place for it.
After all, how many of us humans are native to the areas we call home?

Rudy, the reason I was curious was that Hemerocallis fulva is listed in "Plant Invaders of Mid-Atlantic Natural Areas", so somewhere not too far from me, and possibly right by me daylilies are an issue. I'm not nuts about where I have some daylilies in my yerd, and if they were seriously invasive, that might give me the push to pull them out. Due to DH's preferences (and sometimes my just falling in love with a plant), I will probably continue to plant exotics, but I do want to have the information the plant's invasiveness status if I can.

I think the consensus here is that the hybrids aren't a serious problem. It's good to know since they're used so extensively in my neighborhood.

Thanks. -- Lori

Here is a link that might be useful: Plant Invaders of Mid-Atlantic Natural Areas