My 55 Gallon
uses HC as a foreground and lilaeopsis as a midground. Robert is right, they are both slow growers, but lilaeopsis does grow a bit faster than the HC.
In my tank, the lilaeopsis eventually started to grow under and lift up the HC. it does not displace the HC though since the lilaeopsis provides a nice base for it to grow on. Occasionally a few stray blades will stick out of the HC, but I just trim those off occasionally to keep it all looking tidy.
Again the lilaeopsis does lift the HC over time. My HC foreground ended up an inch higher above the substrate than I wanted. I'm still satisfied with the results though.
Actually here's a quick photo to illustrate what I mean: