Green roofs in hot climates got off to slow start. They were up against a lot: extreme temperatures, intense rainfall events and long periods of drought. Plant roots — and the matter they live in — have to remain cool enough to survive and be able to retain moisture. No small feat on a Central Texas rooftop.

To address these issues from the roof up, as it were, Wildflower Center researchers developed SkySystem™, a planting medium specifically formulated for green roofs in hot climates. Even in hot Texas summers, it helps keep roots cool and soil moist. An added bonus? It’s comprised of 100% recycled materials.

Center Environmental Designer John Hart Asher says most planting media prior to SkySystem was made up of components that had a negative environmental association, such as sand (which requires mining). Or, if they had green products such as coconut coir fiber in them, that matter wasn’t locally sourced. Faced with no good available option, the Center decided to make its own.

SkySystem consists of 100 percent recycled content — all of which is locally available. It’s a low impact development (LID) mix, including material that’s organic, like compost, and mineral, such as pulverized brick. Asher says the custom recipe created at the Center is able to prevent big temperature fluctuations, which makes for healthier, stronger roots.

Currently, SkySystem is only used on projects contracted through the Wildflower Center, but a major green roof manufacturer is considering licensing the product, which would make it available for purchase by other developers and designers.


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Discover the Native Plants of North America