Never had the creeping variety, only the clumping (L. muscari) -- and it fills in at a pretty good clip if happy.

My neighbor gave me liriope 25 years ago--it doesn't creep, it gallops--one of those plants that I would like to ban from the earth. It spreads by both seeds and runners.

nothing creeps fast enough.. and then a few years later.. world domination has come ... lol ...

whats your hurry.. and are you sure it accomplishes your goals.. without fast becoming a problem???

you dont mention how many you are starting with..nor how big the plants are .. usually if you have ground to cover.. you plant many to accomplish said goal faster .. rather than one single planting.. and hoping it covers the earth ...

i suspect whatever you goal is.. its going to take a few years for the plants to get established ... and start moving around ... if you are hoping for anything much faster ... you are probably setting yourself up for disappointment ....

set low expectations.. and you usually remain happy .. lol ...

ken

i have a shady area with an erosion problem. loriope has a tenacious root system that i'm hoping will help. what i planted last year seems to be getting established. I accidently dropped some ajuga in the area that rooted & has really taken off bit it's roots are too shallow though for erosion control. i'm trying some lily of the valley too.