The use of regionally sourced materials for a green roof is very important for a number of reasons. Without using regional materials the environment you create will not be natural to that location. In order to attract the local flora and fauna to the area it is important that the habitat you create accurately replicates the surrounding environment.
There are various factors that change as you move from region to region in the UK. The most noticeable of which is the plant species found. Due to climate changes, soil variations or coastal transitions, different species adapt to survive in different areas. The change in plant species will have a knock on effect on the animals that live in the area. Vegetation offers food, shelter and nesting material for the local fauna, which will change depending on which plant provisions there are.
Butterflies need specific plants in order for their larva to feed, and different species for the adults to collect nectar from. For example, the Scotch Argus butterfly needs either Purple or Blue Moor-grass for its larva to feed on. Without one of these plants these butterflies will not survive in that region. Due to the fact that only these two species will support these butterflies, the species is only found in North-Western Scotland and Northern England.
By matching the plants you use on green roofs to the local vegetation, you ensure the wildlife in the area can flourish and use the roof to nest and feed. If the plants are not matched to the surrounding area they will be wasted, as no wildlife will use that particular species. If you planted Blue Moor-grass in southern England there would be no species to benefit from this plant.
Similar to sourcing local plants is the use of local substrates. As plants are adapted to grow in their natural soils, using substrates from different regions could provide different pH or nutrient levels which would cause poor growth of the plant. In order to make sure the roof remains healthy it is important that substrate and vegetation are sourced locally.
Sky Garden has excellent experience in sourcing regional plants and substrate across the UK. We don’t believe in cutting corners when it comes to green roofs. They are worth doing correctly in order for you and the environment to reap all the benefits they offer.