Everything about Sedum

Sempergreen Sedum roofSedum and extensive green roofs are so intertwined that in practice people often talk about Sedum roofs. Why is that? What is Sedum and what makes Sedum so suitable for extensive green roofs?

What is Sedum?

Sedum is also often known as stonecrop and is a genus of the Crassulaceae family of succulent plants. This family consists of four to five hundred species and thousands of different varieties. Succulents are plants that store water in a part of the plant. Sedum stores water in the leaves, and this is why Sedum is often referred to as a leaf succulent.

The metabolism of Sedum differs from other plants. At night, carbon dioxide is absorbed through the stomata and converted into malic acid. During the day, under the influence of sunlight, the malic acid is decomposed and photosynthesis takes place. The stomata in the leaves are only open at night. During the hot and dry day, moisture loss is minimized.

Many Sedum species originate from the northern hemisphere and around the Mediterranean in particular. However, Sedum can often be found in North Africa and South America in dry and/or cold areas where water may be scarce.

What is a Sedum roof?

Under an extensive green roof or Sedum roof we also include vegetation that is more or less self-perpetuating and that can further develop and maintain itself. Roughly speaking, extensive green roofs have a substrate thickness of between 4 and 15 cm and a weight per m2 of 30 to 220 kilo.

A green roof with a weight of 30 kilo/m2 generally consists of only Sedum vegetation, while a green roof with a weight of 220 kilo/m2 consists of biodiverse vegetation, such as a mix of Sedum varieties, grasses, herbs, host and nectar plants.

Compared to an intensive green roof, the installation and maintenance costs of an extensive green roof are relatively low.

What makes Sedum so suitable for a green roof?

  1. The root system: Sedum has very shallow roots, a key requirement for an extensive green roof, considering the modest depth of the substrate layer.
  2. Sedum is also drought-resistant
  3. Sedum needs relatively little nutrients and maintenance compared to other types of plant
  4. Sedum is very resilient to diseases and insects
  5. Sedum is also very adaptable: due to its capacity to adapt its metabolic system in periods of drought, it is able to survive in extremely dry conditions where other types of plants would die. And furthermore, Sedum recovers remarkably quickly as soon as water becomes available again.

Why opt for Sempergreen Sedum blankets?

Sempergreen conducts on-going research into the quality of Sedums and other plants for extensive green roofs. Thanks to the many years' experience, Sempergreen has gathered much knowledge and expertise about Sedum varieties and other plant species. By no means are all Sedum varieties suitable for use on extensive green roofs or in a Sedum vegetation blanket. For instance, tall or large-leaved Sedum varieties are less suitable, because the plants may break or become damaged when the mat is rolled up or laid out. Sempergreen selects only the most suitable Sedum varieties for cultivating the various vegetation blankets. So you can be confident that your green roof really will remain green all year round. Naturally!