if ur asking me, personally i like roots to be more towards the back corners. that way it gives plants room to bloom in front of it (foreground-mid ground plants) the way you have it it seems busy :P
id shift some of the rocks towards the middle back towards the corner as well. IMO i think it steals away from the focal point which is your center lane there.
just my two cents
should look great regardless once your plants take over ^^