proper planting of anubias

All the Anubias species should be planted leaving the rhizome uncovered. Which means you can plant it virtually anywhere, on wood, stones, or anything you can attach it to...even the substrate. But keep in mind, you only plant the roots into the substrate, while leaving the rhizome uncovered.

Remember the rhizome has roots coming out of it, and roots are used to extract the nutrients from the water/substrate. It is not the rhizome that extracts the nutrients.

Many rhizomatous plants, in the aquarium and in the garden, are prone to rot and disease when the rhizome is covered. Even here in zone 5, when we plant iris in the garden the rhizome is on the surface, not buried, because of rot issues. The same goes for anubias in the aquarium.