I can't speak for your zone, but here in my zone (7b) its very hardy, just as much as the non-variegated kind. My variegated liriope stays nicely in clumps but the non-variegated tends to spread outside the clumps more readily, although not in any way invasively.

Planted in full sun, either kind will need to be cut back to about 1" every late winter/early spring. Planted in shade it can sometimes go 2-3 years before needing the annual cut back.