I prefer real plants. I'm a plant person. I do have some fake plants in with my fire belly toads though.
Pothos is the #1 plant I suggest. They are tough and can withstand the weight of a whites tree frog. They look like this:
For substrate, I mix together 50% coco-husk/eco earth, and then 50% ORGANIC potting soil. It MUST be organic. Miracle Grow makes an organic and its easy to find.
Rinse out all plants very well. I usually stick them in the sink and get out as many of the little white balls as possible, and do a few rinses of the leaves and dirt. Then you can either plant it in a pot or right in the substrate. If you can find a tall pot to put it in and put the pot in the tank, the frogs might find a nice hiding spot behind the pot too.