rooted plants should be rooted, even in gravel, since the roots can and do get nutrients there, from uneaten fish food and fish poo which sinks in between gravel bits, thus why non-live-planted tanks need gravel vacuuming. with live plants you may still need to vacuum up the excess (more likely if you have more fish than plants) but it's often discouraged as it can be damaging to your plants, especially delicately-constructed ones like hornwort and rotala which can be torn to bits by a careless swipe of the siphon.
So remember, when you're feeling very small and insecure,
How amazingly unlikely is your birth,
And pray that there's intelligent life somewhere up in space,
'Cause there's bugger-all down here on Earth.
Loki/Grendel/Gail/Beowulf/Camilla/River/Bathory/Arwen/Lafayette/Deb/Jack Skellington (soon)