Tree frogs prefer plants with tall sturdy leaves. They like to perch on the tops and sleep on the undersides of them. You can add some in. Be sure to rinse off dirt, bugs, and especially fertilizers before adding them to the tank.

Be careful using rocks. Be sure they are larger than your frogs mouth so they don't actually ingest them while eating their crickets. Or cover them with substrate. If the rocks are under water it's ok. It depends on what kinds of frogs you're going to have.

Try making a post on plants for vivariums. Pothos, rhododendrons, philodendrons, bromeliads work well depending on how you're going to set it up.

Hope this helps .