Are they actually eating them or uprooting them to get to food? If they are actually eating them try adding in a solid veggie contect food into your feeding schedule. Geos dig around anything that digs into the substrate because that is a place for a potential food source to collect. Try anubias, java fern, java moss, basically anything that ties to a rock or piece of wood.
I have never had any issues with any of the species I keep actually consuming plants, just playing the "who can find the roots fastest and make this green thing float" game...