As any landscape architect knows, finding hard-wearing and long-lasting plug plants for green roof projects is no easy task.
Plugs are traditionally grown in rich, fibrous peat that dries out irreversibly once they are deprived of water. This is fine for most applications, but on a rooftop it means that roots are unable to become established in the substrate and the plants are much more likely to die.
But now there is a high quality product that is revolutionising green roofs– Boningale GreenSky’s SkyPlugs.
Backed by academic research and development by green roof technology experts at the University of Sheffield’s Green Roof Centre, SkyPlugs are specifically engineered for green roofs.
Devised to thrive in the harsh conditions of a rooftop environment, SkyPlugs are nurtured in a mix of peat-free growing medium and substrate that mimic the gravelly and poor medium that they are planted out in. This ensures the rootball is strong and is able to grow out of the plug space as soon as possible, giving them maximum chance of establishing and surviving.
Maggie Fennell, Manager of Boningale GreenSky, the green roof department of Boningale Nurseries that was set up in partnership with the University of Sheffield Green Roof Centre, said researchers found this method to be effective because plants do not experience the “shock factor” when being transplanted into the substrate.
“This ‘shock factor’ immediately inhibits their natural growth,” she explained. “It’s for this reason that many traditional plug plants used for green roofs do not establish properly and have to be removed from the site.
“Creating a green roof requires very careful planning and attention to detail because of the complexities involved in creating such an ecosystem.
“Working with the University of Sheffield, we found that growing the plugs in the same kind of medium that they will be planted in ensured better survival. This means the roof looks and performs how it should do for longer.”
The 65cc volume of the SkyPlug has a 62mm depth, which is ideal for planting into lightweight extensive green roofs, and provides a good width to encourage faster establishment and coverage.
SkyPlugs also offer better flexibility for green roof designers than matting or seeds because they can be planted exactly where they need to grow; allowing architects more freedom in the design.
With an expanding range of more than 100 varieties of plant to choose from – from classic sedums and wildflowers to more exotic alpines and bulbs – architects also have plenty of choice when it comes to creating a colourful and diverse rooftop environment. Plus, their longevity means that they are the ideal choice for contractors who also have to maintain the roof gardens because fewer replacements are necessary.
The unique growing technique used in the development of the SkyPlug, also enables GreenSky, upon request, to contract grow specific plant species to individual contract specifications.
GreenSky experts can offer specialist help and advice to landscape architects in the planning of green roofs, while technical data relating to the SkyPlug can be found on the GreenSky website.
Boningale GreenSky will be exhibiting the SkyPlugs at EcoBuild, the world’s largest event for sustainable design, construction and the built environment, which is being held at ExCel in London, on March 5-7, 2013.
“Feedback so far on SkyPlugs has already been phenomenal and we are looking forward to showcasing the product at EcoBuild, which attracts tens of thousands of the most influential professionals from the industry,” said Maggie.
“We know this high quality product will capture the imagination of landscape architects, who want to develop stunning green roof features that will not only enhance biodiversity and the environment, but will also look fabulous for years to come,” she added.