What method of planting is most suitable for my green roof, and how soon will the green roof develop?
Extensive green roofs incorporating sedums can be planted by either plug-planting, hydroplanting, or by installing pre-cultivated sedum mats. Although hydroplanting is the most economical method, it will take two full growing cycles to achieve good coverage. Plug-planting will give immediate coverage, but the amount of coverage depends entirely upon the frequency of planting. A good cost-effective solution is to plug-plant at 15-20 plants/m2 and to infill between the plants with hydroplanting, which will eventually give complete coverage. Sedum mats will provide immediate total cover, but need to be ordered well in advance to ensure availability. The contract also needs to be very carefully co-ordinated because the sedum mats need to be installed and watered in within a short time of delivery, as they have a limited transit life. Intensive green roofs on the other hand, can be created in any way the client desires i.e. by seeding, or planting seedlings/saplings, semi-mature trees and s
