When people think of green roofs, many of them tend to think of a roof covered in grass or perhaps wild flowers such as those typically found in a meadow like corn flowers, poppies and marigolds. These do exist, but typically it is the sedum roof that is most popular amongst green roofing specialists and for some very good reasons. However, when mentioned to clients, the term ‘sedum roof’ often gives rise to the question ‘what is sedum?’ and then with the follow up question of ‘why use sedum?’
Well, it is these questions that we hope to answer here.
What is Sedum?
There are over 600 varieties of sedum plants and are found throughout the northern hemisphere. They are a flowering plant and are commonly known as stonecrops on the grounds that many of the genus still manage to grow and thrive in some quite challenging locations. As succulents they have water storing leaves and their flowers mainly have five petals.
The sedum plants are found in a variety of habitats and so naturally differ in their requirements, some thriving in hotter climates while others prefer a cooler environment. Putting their pretty flowers to one side, it is this diversity alongside their robust nature that makes them so popular amongst gardeners and in more recent times by roofing specialists as an integral part of their green roofing systems. However, it is worth noting that though many sedums flourish in tough environments there are just as many that like a rich fertile soil.
Why do we like to use sedum on our green roofs?
Sedum offers a robust vegetation covering which means limited maintenance work for our clients. Due to the obvious location of roofs, they do tend to take the brunt of the weather at all times of the year. As mentioned earlier, the sedum plants are tough and so are able to weather extreme conditions and yet still look good!
Sedum Roof Maintenance
Sedum is relatively easy to keep and only needs a shallow growing substrate. The Riefa green roofing system’s substrate or growing medium is made of a single layer of 36mm board which is ideal for sedum. However, like all living roofs, the nutrients within the substrate do get depleted with time and may need a fertilizer top up to aid continued growth and wellbeing. One great thing about having a shallow substrate is that it helps to keep many invasive species out as they often require a deeper root system. Any unwanted species can be easily removed by carrying out an annual inspection.
Sedum roofs are great at holding water so do not tend to need additional watering unless there is a severe drought. Excess water will be taken up by the plants themselves or steadily released back into the drainage system.
The sedum plants are added to the roof in a kind of blanket or carpet that is simply rolled out on top of the Riefa substrate board. The sedum thick blanket may contain as many as 10 different species per square metre thereby providing an instant greening effect. This is very pleasing for Riefa customers who like the instant result this provides.
Unlike wild flowers or grasses, sedum looks good most of the year round. Wild flowers tend to only flower for a few weeks in the summer, whereas the sedum roof will provide an attractive and everchanging view throughout the year.
The final reason and probably the most important as to why roofing specialists like a sedum roof is because they simply look great when in flower.
Can Riefa provide sedum plants?
Yes we can. To chat about your green roof project call us on 0844 057 0359. We’re happy to give advice and can supply everything you’ll need for your green roof including a root resistant membrane, your sedum and importantly your lightweight, organic green roof growing medium