Green roofs can look vibrant and exciting without high maintenance, says Boningale GreenSky’s leading plant expert.
Maggie Fennell, manager of the innovative Shropshire-based company that pioneered the development of SkySuperstrates and SkyPlugs for green roofs, said because so many colourful and hardy plants can survive the harsh conditions of a green roof there is no longer an excuse for boring planting schemes.
She said when green roof designers use 150mm deep substrate, it opens up the types of suitable species that can be planted because there is room for extra root growth and more capacity for water storage.
“Extensive green roofs are traditionally dominated by sedums because they are extremely drought tolerant, or by wildflowers to support biodiversity. But, clients are increasingly reluctant to use wildflowers because they can get large and unsightly, resulting in a large maintenance burden.” explained Maggie.
Sometimes this leads people to opt for a sedum roof with poorer species diversity and shorter flowering period.
Instead, Maggie says planting a range of low-growing native wildflowers and evergreen plants with a wide variety of forms and flowering times would provide the best aesthetic and biodiverse performance with the lowest maintenance requirement. Hardy and drought-tolerant alpines and cultivars also thrive brilliantly on extensive green roofs, too.
To boost seasonal and all-year colour, herbs and bulbs should also be planted.
