Succulents are plants with the distinct characteristic of retaining water. Some of their parts, such as leaves and stems, are usually thickened and fleshy so that they can store water more easily. They are also sometimes called water storage plants.
Succulents are generally very low-maintenance, and we can even say that they are self-dependent to some extent. They are ideal for your green roof because they will cover a large area of it, and they don’t need a lot of soil to grow. They are ideal for shallow substrate roofs, and their water needs are minimal – you would only need to water them occasionally, especially during drier parts of the year.
Apart from that, there are also different-colored species that will liven up your roof and add some variety and color. All the plants should be planted at high density so that they cover the substrate adequately – around 16 per square meter. Some of the best succulents for green roofs are sedums, so here are some examples.
Sedum sarmentosum is a green succulent, also known by the name of gold moss stonecrop. It is an evergreen and can last for a long time, so it is also good for colder climates. During summer it has a special yellow-colored inflorescence.
Also known as Caucasian stonecrop or two-row stonecrop, Sedum spurium is an herbaceous, deciduous plant that usually has pink flowers, but they can also be in other colors, such as red or white, depending on the type.
What makes them ideal for green roofs is that they can grow in any kind of soil and they don’t have to be exposed to sunlight at all times – they can withstand a couple of hours of shadow per day. Sedum spurium grows 10 to 15 cm tall, and its leaves turn red in colder seasons.
Sempervivum translated means “live forever”, and that is also one of the names this plant goes by, along with “houseleeks” and “hen and chicks.” It is a perennial succulent plant that can live for a very long time with little maintenance. They are very good for cold climates and demand full sun exposure. They come in a variety of different colors and can spread very easily in suitable conditions.
Grasses are usually tricky to plant and demand a bit more care, but some types are great for green roofs, and can withstand its harsher conditions. They are great for covering larger areas and combine very well with succulents, both aesthetically and regarding growing conditions. Their roots are not big, so they require little soil.
Carexflacca or Carexglauca:
This grass species is also called blue sedge and functions as an ornamental plant. It is resistant and good for different kinds of soil and climates. It will be a great addition to your roof with its blue leaves and a round shape. It is very low-maintenance, doesn’t need full sun exposure and is drought-resistant.
This grass is also called “bowles’ golden sedge,” it is yellow and doesn’t need any particular maintenance. It can grow in moist and wet soil, and it is also good for rainy and humid areas.
A significant characteristic of groundcovers is that they grow horizontally and spread very quickly and easily. They are used to cover big areas of soil and are great at preventing the spread of weeds. This makes them ideal for green roofs.
Ophiopogon japonicus or mondo grass is grass-shaped, but it is actually a flowering plant. It grows vertically and can be 10 cm high. It is a perennial, evergreen plant which makes it ideal for cold climates. Its lilac flowers will give your roof a nice touch of color. It can grow in the shade or partially sunny areas and needs moist to wet soil.
This is a dwarf perennial plant also known as trailing ice plant or pink carpet. It is referred to as “pink carpet” due to its color and the fact that it spreads very easily and can quickly cover the entire area where it is planted, reminding of a carpet. It can grow from 10 to 15 cm tall.
Its flowers can be in various colors, from pink to purple and orange. Generally, it needs full sun exposure, but they are known to tolerate a couple of hours of shade per day. It grows best in wet soil, and in dry, hot climates.
Whether you opt for succulents, grass or groundcover plants, your green roof will undoubtedly look beautiful. There are many beautiful and colorful plants in all of these groups of plants. You can choose one type or a combination of several and have a beautiful, flourishing roof garden.
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