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Saturday - April 30, 2011

From: Austin, TX
Region: Southwest
Topic: Green Roofs
Title: Planning and designing a green roof from Austin
Answered by: Barbara Medford


I am in the planning stage to decide about planting a green roof as part of new construction. My ideal plant life on the green roof would have minimal root structure (deeper roots mean deeper soil means more structural load on the roof) so probably 0 to 12 inch high plants, require little maintenance (ideally just let them grow naturally with as little human intervention as possible), be tolerant of full sun year around in Austin, Texas (we are talking about a roof here) and need little watering (I will be installing sprinklers to water if needed and to start the green roof off right) and do well in the light artificial soil of a green roof (clayish soil is heavier which means it requires more structural support). On top of this (assuming I can find a mix of plants that match the above), it would be nice to have some flowering plants in the mix. I don't have a problem with "weeds" as long as they meet the above criteria. It may make sense to do this in stages with the initial stage being a native grass and once that is established adding in other species. Since this is an artificial environment that is meant to take advantage of native plants, I need help on every level. Names of plants, sequence and season for planting, care from initial soil installation to seeding/planting and growth from initial to fully mature plus any cautions.


This is a bit beyond the scope of the Lady Bird Johnson Wildflower Center Mr. Smarty Plants team. The Wildflower Center has, however, done extensive research and has onsite "sample" roofs that can be viewed. Go first to the home page for Green Roof Research, and follow links on that page for more information. The last link on that page will take you to our site on Native Green Roofs. From this page, you are also linked to a Species List from Wildflower Center Research. You may visit the Starbucks at Circle C Ranch to see one of our projects. If you just search the Internet on "green roof" you will get many other resources. This is the sort of a project where consultation with an expert can make a big difference in the success of your project. Mr. Smarty Plants is good about discouraging the planting of non-native species and transplant shock but engineering, not so much.


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