Mine grows pretty quickly. I have 220 W PC over a 90 gal w/ CO2 and fert dosing. I find it tries to grow in a straight line, no matter what. Mine goes under driftwood, through other plants. When I see a runner going off in a unwanted direction I either bend it around to go throught the "lawn" again or I cut a bit of it off and replant where it is thin.
I had good luck with it with CO2 and about 2.75 wpg.
It took quite a while to get started though.
I found that if it was shaded it would tend to stall and then get covered by algae.
After a while when it got really thick I would haul the whole mass out and replant a few pieces. It would always come right back.