Plants for green roofs: everything you need to know

How do plants reach your roof?

Before we consider the question of which plants are suitable for green roofs, we must first ask: How do these plants actually reach my roof? Extensive green roofs can be planted in two different ways. On smaller and flat roofs, such as garages or carports, you can even install green roof coverings yourself in just a few, very easy steps. Before green roof coverings can be planted, however, you must ensure that you have a professional and competent green roof build-up. The conditions for the green roof covering are determined by FLL guidelines.

Important: If you are not sure whether your roof fulfils conditions of FLL guidelines, have it checked by a roofing contractor.

Planting green roofs - Sedum shoots

Sedum shoots are shoots from sedum plants. These living plant parts are especially suited to extensive green roofs and can easily be scattered on existing roofing substrates. This type of planting is mainly used in flat green roof coverings. Thick-fleshed leaves of the individual sedum plants are very resilient to dryness and heat resistant, and are also able to cope with a low water and nutrient supply. They can also manage for weeks without any water, so that additional watering of greenery is usually not necessary after the growth period. In addition, they are especially easy to service and maintain, and are therefore especially suitable for green roofs on garages, carports or flat roofs on houses. After some time, the sedum shoots selected form a closed plant covering and provide a beautiful-looking surface covering for your green roof. After spreading the shoots, the roof must be sufficiently well watered so that the entire substrate is completely saturated with water. You will need approximately 100g of sedum shoots for every  green 1m² of green roof. The colour of flowers of sedum shoots range from white to pinkish red to a beautiful yellow. During the flowering months between approximately May and August, extensive green roofs change their appearance according to the individual flowering periods of sedum shoots - with the right mixture, your green roof will light up a different colour every season.

Planting green roofs - sedum mats

Especially for (steeply) inclined roofs with angle of inclination up to 45°, so-called sedum mats are especially well suited for the yield of plants on your green roof. Sedum matting is frequently used as a planting option for (steeply inclined) sloping roofs and for sedum instant green roofs. Vegetation mats are produced according to FLL guidelines. This matting is planted using between 6 and 8 different species of plants and must always exhibit at least 90% growth covering at time of delivery. The special characteristic of these vegetation mats is that the sedum has been planted on a special coconut fibre mat and / or a specially developed build-up medium. Plastic reinforcements on top of and beneath coconut fibre matting which are added to the vegetation mat in specific cases, provide additional stability and especially secure bonding on steeply sloping roofs. Sedum mats are laid directly onto the existing roofing substrate in a similar way to rolled turf and then take root in the green roofing build-up in a very short time. The succulent sedum plant is ideally suited to extreme location "roofs", as it can store water in its leaves and will thrive well even under extreme weather conditions. The particularly simple installation principle for these mats permits rapid and simple installation.

Criteria for plants on green roofs

Selecting the right plants for a green roof depends on various factors, which must be considered in different manners from roof to roof. Every roof is a little bit different, and so green roofs and their plants differ too. In the case of extensive green roofs, the most important thing is to select plants that are relatively easy to spread, are easy to service and maintain and last but not least, are especially robust. Nevertheless, the plant species and the method of application differ in some factors.

Examples of plants used on green roofs

There is a long list of possible plants for use on extensive green roofs. Despite the extreme site conditions, there are some species that can combat dryness and drought, frost and wind and not only provide an especially beautiful appearance for your roof, but also offer environmental benefits. Species of sedum (yellow stonecrop) belong to the stonecrop family. With more than 420 different species, sedum plants are one of the most extensive genera within the stonecrop family. Along with houseleeks, these species are ideal for green roofs, as they can store water and are largely self-sustaining after a short time and do not require much servicing or work. We use only high-quality sedum shoots and matting in our products, with 5 to 8 different species of plant depending on their availability and the season. In order to be able to provide you, the customer, a simple and convenient solution, we here at TOPGREEN keep ready prepared mixtures in stock, which have been put together in an ideal manner for green roof coverings. The exact composition depends on the availability of plants and the season.