A sedum (or green roof) is the ideal choice for a flat roof garden building, providing an attractive feature that will attract wildlife to your garden whilst offering the benefit of both sound reduction and insulating properties. At Garden Affairs we offer a beautiful green roof on all our flat-roof buildings. Whilst a green roof is low maintenance, if you want it to last, and continue to attract wildlife, it will require some love and attention, a little care will help your roof to flourish and look good for years to com.e
There is a common misconception that sedum green roofs will be completely green and that sedum plants are always green. This is not the case, in fact, they consist mainly of low-growing, drought-tolerant sedum plants of many varieties that change colour and appearance with the seasons. There are actually about 8 – 10 different varieties within the sedum carpet, some very similar in appearance to others. Be aware that not all varieties will survive in certain locations because of varying climatic conditions, but because of the vast variety of plants, the stronger and better-suited plants will take over to ensure consistency across the roof area.
Over time it’s not uncommon for weeds and moss to make an appearance in the sedum but due to the nature of design, creating a free-draining and predominantly dry environment will assist the sedum to thrive and discourage unwanted vegetation. In terms of maintenance requirements going forward, a yearly weed and feed in Spring with a slow-release granular fertiliser are essential to help revive your plants after a long winter and ensure the roof stays in tip-top condition. Obviously, the longer this is left then the more work will be required to get the roof back to a more manageable state.
Whilst Sedum can deal effectively with dry conditions, and will usually change from being a vibrant green to a browny-red hue, don't be alarmed, as it should return to normal, however, if dry conditions persist, it is important to give the roof a good watering - a ladder and a hosepipe will do the job nicely.
Periodically check for any unwanted vegetation, e.g. weeds/ grasses/ saplings and moss. Although weeds are a problem of aesthetics rather than damaging the roof, large areas of weed or grass should be removed, as should saplings. After the removal of weeds treat the area as if it were a bare patch (see below). When inspecting your green roof, it's also a good idea to check for evidence of pests by lifting small areas of the sedum mat to check for both plant and root pest attacks.
Bare patches can be repaired using rooted clumps of Sedum from areas of abundant growth into bare patches by pressing gently into the growing medium, finishing with a light sprinkling of MC1 growing medium and nutrients to improve and speed up root growth.
