Posted: 09/02/2016 at 10:31
Don't worry, it'll grow!
As Dave says, take a few bits with roots on and pot them up and put them indoors and they'll take off a bit earlier.
I've got spearmint and Bowles Applemint in large bottomless buckets sunk into the ground with the rims sticking up about 4 inches above ground to try to keep the runners in check. They've been there about 3 or 4 years now, top-dressed with home-made compost and Fish Blood and Bone each spring.
This spring I'll dig them up, tease the very congested roots apart and replant the younger ones in fresh soil as before, to rejuvenate the plants.