Cool in summer, warm in winter and green throughout the year: a living roof with plants like rockfoil, stonecrop and sempervivum is not only sustainable, but also lovely to look at.
Moving towards carbon neutral
Living roofs are attractive to look at and are a useful addition to the natural environment. They increase the biodiversity your area and purify the air because the plants absorb and filter carbon emissions. A living roof attracts insects (and therefore birds as well), is sustainable and also insulates: not just in terms of temperature, but also muffling external noise. Because the plants take up water, you are less likely to suffer flooding in the event of heavy rain. It requires virtually no maintenance, and almost every roof is suitable for it. The Green Covering plants are also suitable for small roofs such as a lean-to, shed or birdhouse, and for vertical wall gardens.
These are the Green Covering plants
Stonecrop produces white, yellow and red flowers. In addition to the well-known ground-covering species there are also a few species that grow a bit taller.
Rockfoil grows in decorative rosettes with white, red, pink or purple flowers that do not get taller than 15 cm.
Sempervivum blooms between April and August with pale yellow, white or pink star-shaped flowers that rise some 10 cm above the rosette on palm-like stems – quite a sight!
Rockfoil and sempervivum particularly occur in mountainous regions such as the Alps, Dolomites and Caucasus, whilst stonecrop grows throughout the northern hemisphere, particularly in dry rocky regions and all in between walls and stones.
All the Green Covering plants are succulents. A succulent is a plant that stores water in its roots, stem or leaves in order to get through periods of drought. You can identify them by the thick, fleshy leaves that act as a reservoir. The name succulent comes from the Latin word ‘sucus’, which means ‘sap’.
Roof tip Green Covering plants are often offered in a mixed mat similar to turf: roll it out, give it some water, leave it to secure itself.
7 steps to a living roof
Step 1 Carefully brush the existing roof clean.
Step 2 Make sure that the drainpipe remains clear by placing a wire guard over it.
Step 3 Place plenty of gravel around the guard so that the soil cannot get washed into it.
Step 4 Roll out a drainage mat on the roof and cut it size.
Step 5 Cover the mat with an artificial substrate for plants.
Step 6 Distribute the plants across the substrate or roll out a ready-made sedum mix mat.
Step 7 Lightly spray your brand-new living roof so that it can absorb moisture.
“Landscape planners will have the opportunity to make sculptured roofscapes, so that cities appear to be verdant hills and valleys. Streets will become shady routes carved through the undergrowth. Roofs will become mountaintops.” Tom Turner
- Remove weeds and tree seedlings twice a year.
- If the weather is very dry for a long time, water with a hose.
- Feed once a year.
How to achieve maximum visual benefit with Green Covering plants
In theory it is possible to create squares or geometric patterns with stonecrop, rockfoil and sempervivum. In practice a random mixture works best. In that way the plants create an attractive relief, the shades of green, pink and purple work well together, and they will rapidly form a dense carpet on a roof.
Help – I don’t have a roof!
If you don’t have a suitable roof, you can also scatter stonecrop, sempervivum and rockfoil around your garden, patio or balcony in bowls and pots. The soft, voluminous look means they look like big green cushions that create a friendly atmosphere. They also provide fresh green accents at the time of year when most greenery is entering hibernation.