Mix guide
Use the whole range of species available to you on the same roof, either in separate planting areas or all mixed together. Then you have the combined winter interest and drought survival of the succulents, long flowering, colourful mountain plants, and diverse insect-friendly wildflowers.
Simple, low growing roofs can use this technique effectively. Instead of relying on just sedum, interspersing Delosperma cooperii, Lotus corniculatus, Campanula portenschlagiana and a few varieties if Thymus will immediately lift a plain expanse of sedum with seasonal colours and more insects.
A little height and structure can still be achieved with shallower depths, as some plants will establish and survive in 80-100mm of substrate. See our substrate depth diagram for more details.
By using different kinds of planting you can attempt to tailor colour schemes and styles to suit the situation, making an intentional convergence or divergence from traditional ground planting style.
Build resilience in to your planting scheme. In an ever-changing climate with unexpected storms and droughts becoming more of a regular occurrence, different species are likely to perform better in particular years, while other species may suffer. The more variety you have, the better the chances that you will have a great looking roof with minimum maintenance year after year, whatever the seasons throw at it.
In recent years we have seen very varied spring and summer weather: record rainfall in spring has seen Allium schoenoprasm and Allium sphaerocephalon do exceptionally well; whereas during a much drier and sunnier spring, Achillea millefolium performed better than its neighbouring plants. With increasingly unpredictable weather patterns, it is hard to say which species will thrive, and which will just survive.
