When a million-strong swarm of ladybirds landed on Blackdown Horticultural farm recently, every time the staff ventured outside they were coated in insects. But the red cloud brought good publicity for their enterprise: green roof installation.
The swarm had arrived to feast on aphids living on pesticide-free sedum plants, a staple of green roofs since these succulents are drought-resistant and thrive in well-drained conditions.
Growing plants on roofs seem an obvious idea in our concrete and asphalt world. The benefits are endless – here are just a few:
- Improved building insulation
- Aesthetic qualities
- Improved air quality in cities
- Reduction of the urban heat island effect
- Provision of habitats for flora and fauna
The Environment Agency recommend a variety of substrates, and the inclusion of wildflowers among the standard sedum, as well as adding logs, sand and shingle to attract the widest variety of invertebrates and birds – see illustration above.
But green roofs are not only for urban areas. The Rolls-Royce factory in Sussex, with one of the largest green roofs in Europe, has succeeded in blending into the countryside. The sky larks, at least, have accepted it, using the roof to nest, safe from ground-patrolling predators.