As the concern for our environment continues to grow, more and more homeowners are looking for ways to make their properties greener. One innovative way you can contribute to this global effort is by installing a green roof. This eco-friendly practice can reduce the impact of your home on the environment, provide a new habitat for wildlife, and potentially lower your energy bills. But what exactly is a green roof, and what are the best plants to use for a UK home installation? This comprehensive guide will answer these questions and provide you with all the information you need to get started on your green roof journey.
Understanding Green Roofs
A green roof, also known as a living roof, is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. There are two types of green roofs: extensive and intensive.
An extensive green roof is a shallow, low-maintenance system. It is lightweight, and can be installed on a wide range of buildings without requiring additional structural support. This type of roof is typically planted with hardy, drought-resistant plants such as sedums.
An intensive green roof, on the other hand, is a deeper, high-maintenance system. It resembles a traditional garden, with a wider range of plant options, including shrubs and even small trees. This type of roof is heavier and may require additional structural support.
Best Plants for an Extensive Green Roof
When deciding which plants to use for your extensive green roof, it’s important to consider the UK climate. The plants will need to survive cold winters, as well as potentially hot, dry summers.
Sedums are a popular choice for extensive green roofs in the UK. These resilient plants are known for their ability to survive in harsh conditions. They’re drought-resistant, can tolerate poor soil, and need very little maintenance. Sedums come in a variety of shapes, sizes, and colours, meaning you can create a visually appealing roof that is also environmentally friendly.
Another good choice is wildflowers. These can attract bees and butterflies, supporting local biodiversity. Wildflowers can be mixed with sedums to create a more diverse and visually attractive roof.
Best Plants for an Intensive Green Roof
If you’re considering an intensive green roof, you have a wider range of plant options. However, these plants will require more maintenance, including regular watering and pruning.
Grasses and herbaceous perennials are a good option for intensive roofs. These plants can provide a rich, lush look, but they do require regular watering and maintenance.
Small trees and shrubs, such as junipers and boxwoods, can also be used on intensive green roofs. These plants can add height and interest to your roof, but they will need regular pruning to keep them in check.
Key Considerations for Green Roof Installation
When planning your green roof installation, there are several key considerations to bear in mind.
Firstly, you need to consider the structure of your building. Green roofs add weight to your roof, so you need to ensure your building can support the additional load.
Secondly, you must consider the drainage of your roof. Green roofs need to have good drainage to prevent water from pooling and causing damage. A drainage layer is typically installed below the growing medium to help water flow away from the roof.
Thirdly, you need to think about the maintenance of your green roof. Extensive roofs require little maintenance, but intensive roofs will need regular watering, feeding, and pruning.
Lastly, you should also consider the local climate. The plants you choose need to be able to survive the weather conditions in your area.
Benefits of Having a Green Roof
Aside from the obvious environmental benefits, green roofs can provide a range of other advantages. They can insulate your home, helping to reduce energy bills. They can also increase the lifespan of your roof by protecting it from the elements. Furthermore, green roofs can provide a new habitat for wildlife, contributing to local biodiversity. Whilst the upfront cost of installing a green roof can be significant, the long-term benefits to both your home and the environment can make it a worthwhile investment.
Semi Intensive Green Roofs and Suitable Plants
A semi-intensive green roof is a blend of the extensive and intensive green roof systems. This type of roof is sometimes referred to as a "shallow intensive" roof. It offers a medium depth growing medium, typically ranging between 10 to 25cm. This extra depth increases the range of suitable plants, yet still doesn’t require as much maintenance as a fully intensive roof.
Like the intensive roof system, semi-intensive green roofs can support a wider variety of plants including herbs, grasses, perennial flowers, and certain types of shrubs. However, they cannot support larger trees due to the medium depth of the growing medium.
Examples of suitable plants for a semi-intensive green roof in the UK include lavender, thyme, chives, and other hardy herbs. These not only survive well in the UK climate, but also provide valuable food sources for bees and other pollinators.
Grasses such as fescue and rye can also work well on a semi-intensive roof. These grasses are hardy, drought-tolerant and can provide great ground coverage. They also add texture and movement to the roof garden, creating an aesthetically pleasing environment.
Additionally, certain flowering perennials such as coreopsis, echinacea, and rudbeckia are great choices. These plants add colour and attract beneficial insects, further enhancing the biodiversity of your green roof.
Conclusion: The Impact of a Green Roof
In conclusion, the installation of a green roof is a worthwhile investment that offers a plethora of benefits. Not only does it reduce the environmental footprint of your home, but it also provides a sanctuary for local wildlife, increases the lifespan of your roof, and can even lower your energy bills.
Whether you opt for an extensive, intensive, or semi-intensive green roof, the choice of plants is crucial. In the UK, plants like sedums, wildflowers, herbaceous perennials, and certain grasses and shrubs all thrive well.
Remember, the type of green roof system you choose will determine the range of suitable plants, as well as the level of maintenance required. Regardless of the type, your green roof will become a living, breathing part of your home that contributes positively to the environment and local biodiversity.
So, when you look at your rooftop, see it not just as a cover for your home, but as a potential green sanctuary. With careful planning and the right plant selection, you can transform your roof into a thriving ecosystem that benefits not just you, but the whole planet.
Image credit: All images provided are sourced from reputable green roofing suppliers and are representative of the types of plants that can be used on a UK home green roof installation.
