I grow natives and non-natives as well. As long as the exotics are well-behaved and you enjoy them, there is no reason you shouldn't grow them. I think the author of that post was just looking for a native alternative. I guess it all depends on what you want for your landscape.

No one's going to make me give up my sedums and shasta daisies!

Many of us simply prefer to grow only native plants.

Which is funny, because it IS native where I live, and yes, I do grow it! You should see all the damn North American weeds over here! PF

And yes, depending on where you live liriope IS invasive.

It's on the watch list for SC. Watch: Exotic plant species that are considered to be a potential threat to natural plant communities.

Here is a link that might be useful: SC Exotic Pest Plant Council Non-Native Invasive Plant Species List ­

Liriope isn't something I grow anymore, but at a previous home it was already there. I found it to be a very slow spreader and the seed it produced didn't germinate well. That doesn't mean it isn't a problem everywhere, but in my experience it wasn't.

If you choose to grow only natives, that is your choice. My choice is to grow a landscape that is attractive to wildlife and requires a minimum of care by me or a future homeowner. Invasive spreaders aren't allowed. The balance in my landscape is about 90/10 natives, because of those requirements. They simply perform better under the typically droughty conditions here. Plus, I think Oklahoma has beautiful flora and I love bragging that most of what I grow came from right here.

I just spent two hours digging liriope invasions out of my front yard, and I'm far from finished. I hate the stuff! The previous owners of my house seem to have preferred all things invasive and exotic, excuse me, "easy to grow." Vinca, English ivy, acuba, liriope, wisteria... Plus I've got mimosa, wild onion, forsythia, Bermuuda grass, Japanese holly...

Oh, golly, sounds like you need gallons of whichever spray it is that kills everything.

I can sympathize with you, I ended up with hundreds of invasive plants. I did not know this at the time. Some came from my mother and some from a woman that grew wild flowers and I bought an assortment she had donated to a Public Television Auction. It took me 20-30 years to get rid of all of them and there are still a few hanging around. I wouldn't mind if they would stay where they belong.

Phaltyme:
A memorable line from the book "The American Weekend Garden,"

...some of the worst weeds will be plants you planted yourself, in the beginning!

It echoes in my head whenever I work in the garden.

So it took you decades to get the stuff out. Some things you can't completely eradicate, without resorting to gallons of poison, which is definitely not the way to go. Ivy will always come in from the next yard over. Vinca is a famous escaper of gardens, it is growing all over California state parks now.

I hope to reach an accommodation with the invaders I can't completely eradicate.

PlantFreak:
I had a great laugh reading your post. Naturally, if Japanese plants are weeds all over the place here, the reverse would be true! But I never thought of it. I suppose there's some sort of justice in the situation.
--O

If you think getting liriope out of your landscape is difficult, try bamboo. I could KILL the previous owners.

GYL - everytime I see some TV gardening guru planting bamboo, I cringe. Just say no!

And even if you don't have bamboo on your own property, your neighbor could!

Goutweed should be labelled an invasive as well. Every place I have lived it has been the bane of my gardening existence. It is planted because it fills in hard to garden spots but takes over everything. And will grow under an barrier down to as far as 2 - 21/2 ft. I hate it. Any little bit left in the garden will sprout into a new plant.