Moss on green roof?
This year we are seeing it everywhere: moss on green roofs. It can suffocate the sedum and take over your entire roof. A shame, because you’ll miss the beautiful blooms in summer! Fortunately, moss is easy to remove and prevent. With a few simple steps, you can keep your green roof in top condition.
Where does moss come from?
Moss formation is normal and no cause for concern. Moss likes a wet environment and shade, which is why it will develop faster in winter.
Removing moss is important, otherwise it will have a chance to expand and may suffocate the sedum. Therefore, address this during spring maintenance. With these simple steps, your green roof will stay beautiful and strong for years to come.
Steps for removing moss:
1. Improve drainage
A soil that is too wet is the perfect breeding ground for moss. Check that your drains are not clogged and clean them if necessary. Add extra gravel for better drainage if necessary. A well-drained soil not only helps against moss but also promotes the growth of your sedum!
2. Remove the moss by hand
Use a soft brush or your hands to gently remove the moss, especially if you are working on a green roof. A rake may be too coarse and damage your sedum. Be sure to include the roots of the moss as well, or it will quickly grow back.
3. Adjust soil acidity
Moss thrives in an acidic environment. By adding lime, you lower the acidity and make the soil less attractive to moss. Good news: sedum plants can withstand higher pH levels just fine, so you won’t damage your roof greenery with this. You can buy this lime from sedum-fertilizer.com.
4. Provide more light
Shade and moss go hand in hand. Overhanging branches and shrubs can keep parts of your roof from getting enough sun. By pruning them back, you make sure your green roof catches more sunlight and grows better. This makes it harder for moss to come back.
5. Fill bare spots with cuttings
After removing moss, you may end up with empty spots. To make your roof green again quickly, you can add cuttings. This works best in the summer, when sedum cuttings are readily available. You can also grab some sedum from the gravel edges – you have to remove it there anyway. By adding new plants quickly, you will prevent moss from regaining its grip on your roof.
6. Be patient!
Moss grows most in the winter and naturally diminishes in the summer. If you follow the steps above, your roof will look beautiful again within a few months!
Sedum in winter and spring
Sedum is a hardy plant and can survive well in the colder months. During winter, sedum loses some of its green color and will turn a bit more red. As such, it remains attractive as a roofing company. Also, be sure not to walk on the sedum when it is freezing because the leaves are more likely to be damaged. Moss will also develop faster on a green roof in winter. This is normal and a cause for concern.
Spring is an ideal time to fertilize sedum so that the plant is well prepared for the flowering period. This is also the time to check for moss growth. Mosses thrive in moist and shady conditions, which often occur in winter. If you see moss on your green roof, it’s best to address it now. In our video on “moss removal,” we show you how to do this effectively.
Maintenance of a green roof
Although sedum is very low maintenance, there are some steps that can help keep the plant healthy. Fertilize the plants twice a year, in spring and early fall; use sedum fertilizer for this purpose. Also, weeds may blow in. If so, remove them during this maintenance. Also give extra water to the sedum during long dry periods (you can recognize this by the red color of the sedum in spring or summer). More info on Sedum maintenance can be found on our maintenance page.
Frequently Asked Questions
Sedum needs 4 to 6 hours of sunlight daily.
Some sedum species can thrive in shade, but may have fewer blooms.
For best results, fertilize sedum twice a year, in April and September. Use special sedum fertilizer for this purpose.
After delivery, you can store the sedum mats rolled up for up to two days in cold weather. In warm weather, a maximum of one day. It is important to store sedum mats in a cool, dry place, directly out of the sun. You can also temporarily unroll and water the mats if you can’t handle them right away. For more information on caring for sedum mats, click here.
Fertilize sedum twice a year, in April and September.
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