These mats, which are not yet on the market, are being developed by the forward-thinking people at Altman Plants, the largest succulent and cactus growers in the U.S. Possible uses include throwing them up on bare roadside hillsides where they will require no more than biweekly watering. Developers are also using them for green roof tops or replacement lawns without the wait. Instant low-water ground cover! The sedum mats are grown by just scattering sedum plants on the mat. Anyone could certainly do that on his or her own, but it can take a year or so for the plants to grow in.