Mine never bothered the plants at all. They dig when they're breeding as alot of cichlids do as they move their eggs/wrigglers/fry from pit to pit to keep them safe. They have never exposed the bottom of the tank though, and i can't say i have ever seen then uproot any of my plants.
When mine were in my main tank they were fine with all my plants, which included anubias, vallis, crypts, moss, jave fern, amazon swords etc. They will need a sand or fine gravel substrate though so they can make the pits.