Plants for green roofs with soil depth 150mm

BBC Gardeners' World Magazine

Published: Wednesday, 27 March 2019 at 9:10 am

Take a look at our pick of the best plants to grow on green roofs with a soil depth of 150mm or 15cm.

Save

Building a green roof is an ongoing experiment. Every roof is different and there are no templates to follow. A good rule of thumb is to grow a wide range of plants to offer food and shelter to as many insects as possible over a long period.

Astrantia 'Roma'

Pink flowering Astrantia 'Roma'

This plant is one of the shorter varieties, so it will cope better with dry, windswept conditions. Because 'Roma' is a sterile hybrid, the flowers of this plant last well. To boost the plant's vigour, apply a generous mulch. Flowers May to September.

Great burnet

58480

Fluffy pink flowers of Sanguisorba officinalis

Sanguisorba officinalis is used to control soil erosion because of its extensive root system. These plants have been known to flower better on a roof than anywhere else in a garden!

Aquilegias

58476

Starry yellow aquilegia flowers

If there are any growing in the vicinity, aquilegias and their close relatives semiaquilegias are bound to seed themselves into your green roof. They'll make little colonies in a wide array of colours. This plant flowers from May to July.

Stipa tenuissima

58465

Fluffy Mexican grass Stipa tenuissima

Surely the waftiest, fluffiest grass. Movement is a vital component in any garden and is heightened (so to speak) on a roof. This Mexican grass finds life at high levels perfectly to its liking and should self-seed readily. Flowers July to September.

Viola cornuta

Blue and white flowers of Viola 'Delft Blue'

Although this viola is often grown in a shadier site, the extra sunshine it can enjoy on a roof may change the flower-to-leaf ratio in favour of the flowers. This plant forms gently spread mats and flowers from May to September.

Kate Bradbury says

Make sure you provide additional support to take the extra weight of your roof. Adding thick wooden posts to the four corners of your shed will increase its capacity to hold soil, while using lightweight compost can help reduce the strain.

Kate Bradbury

Don't miss out this Winter

Enjoy expert advice on what to plant and grow this winter, and how to prepare your plot for the year ahead. Enjoy, 6 months for just £31.99

Subscribe now

Great gardening savings - straight to your inbox

Sign up to the BBC Gardeners’ World offers newsletter for exclusive deals, seasonal savings, and early access to special promotions.