Lightweight artificial plants can fall over whether they're outdoors or indoors. When they're outside, the wind can topple them. To keep them stable, secure them the same way you’d anchor regular plants by filling the pots with regular soil and/or decorative stones. Indoor artificial plants like small trees and topiaries won’t fall over on their own, but they can be knocked over by toddlers and pets. The best solution is to position your artificial plants out of the traffic flow in your home and out of the reach of children and pets.