once i had a 180L tank, sizes as 90x45x45cm with about 110w of T8 lighting, combination of 840&865 tubes, average co2 injection, 2cm thick of peat moss laid underneath the gravel, the stargrass was naturally climbing in the bottom without any burying or trimming. every plant was so healthy and green
not sure it was just a coincidence or what, it did sort of carpet the tank.
only problem with the whole thing was really browny water :facepalm:
photo attached