If you have been thinking about installing a living-roof system, choose the plants for it wisely. Opt for those that grow quickly, as well as plants that can self-sustain in your grow-zone. When planning your living roof, consider using the following plants: Grass. Grass and ground-cover is a must for a living roof and it is used to fill in around your other plants. It is important to go with something low-growing and that will thrive in your native climate.