The green roof is an old concept that’s gaining a lot of new traction. Not to be confused with a rooftop garden, a green roof involves literally turning the top layer of a roof into living vegetation. There are two main kinds of green roofs: extensive and intensive. Extensive projects use just a few inches of growing medium and plants with shallow root systems, while intensive ones have at least a foot of growing medium and may support large gardens. In either case, you’ll want plants that can stand full sun, high winds, and lots of exposure – they’re growing way up in the air, after all! Here are our top 5 plants for living green roofs:

1. Hardy Ice Plants – These South African succulents are low growing and very tolerant of heat and drought. Hardy ice plants produce striking daisy-like flowers in the spring, and their bright green foliage changes color brilliantly in the fall.

2. Sedums – A very diverse genus of succulents that produce flowers in more colors and shapes than you can shake a stick at, sedum plants are low growing with a shallow root system and quite hardy.

3. Alliums – The name of the genus of plants that includes garlic, chives, onions and leeks, alliums can also be found in ornamental varieties. Virtually any allium that you plant, though, is going to eventually produce gorgeous pom pom shaped flowers on long stalks. The pom poms are almost always in shades of white to purple. A great tall flower with short roots that pairs great with lower ground cover plants.

4. Herbs – A lot of common kitchen herbs are native to the Mediterranean, which means they thrive in hot, sunny spots. Lavender, rosemary, and sage are good bushy herbs, while thyme and oregano serve better as easily spreading groundcover.

5. Sea Thrift – A grassy plant that grows on seaside cliffs, sea thrift is used to harsh conditions and lots of sun. In the summer, its green foliage is blanketed in small pink and purple flowers.