How to Make Your Roof Green with Native Plants
All over the world, people are planting gardens in the sky. Well not gardens, exactly, and while they’re definitely at a higher elevations, they’re not exactly in the sky.
We’re talking about green roofs, the practice of planting greenery on a rooftop rather than just slathering it with tar and calling it a day. Green roofs have been shown to reduce urban heat-island effects, regulate building temperature, and help manage stormwater runoff, all positive effects in big cities where the greenery that usually performs these tasks has all but disappeared.
Here’s the thing, the plants on most green roofs are pretty boring. To survive the harsh environment of a skyscraper’s roof, vegetation has to be able to survive high winds, prolonged UV radiation and often, a severe lack of water. That’s why a majority of green roofs are planted with sedum, a non-native species that can survive wind and long periods without rainfall, according to Scientific American.
While it may be long-suffering, sedum doesn’t retain water as efficiently as other plants and sometimes it actually absorbs heat instead of reflecting it. Rendering the entire green roof useless. For the thousands of green roofs around the world, this is a problem.
A study, published in PLoS ONE last April, found that in order to reap all the planet-cooling benefits of a green roof, it’s necessary to plant a diverse array of plants, preferably ones that are native to the region. Doing so may take some tender loving care, like occasional watering, but there are worse things than being forced to visit your rooftop oasis once in a while.
If you’ve been thinking about experimenting with a green roof for your home or business, here are some regionally appropriate plants that you might want to investigate.
Northern Sea Oats – an ornamental grass that likes full sun to part shade and well-drained soil.
Butterfly Weed – An extremely hardy, long-lived perennial that displays clusters of brilliant orange flowers Jun-Aug.
Woodland Phlox – This tough little flower is disease resistant, doesn’t mind shade, and delivers a wonderful scent.
Indigo Bush – This bush yields small, dark blue flowers, and loves growing in dry, sandy soil at high elevations.
Swamp Milkweed – This plant offers clusters of upturned pink flowers draw butterflies, and does well in average soil moisture.
Cup-Plant – This stout wildflower an grow to a height of 3-6 feet! The small cup formed by the leaves holds water and attracts birds.
Northern Oatgrass – In the wild, this grass grows on the edge woodland roads and paths, often in thin acidic soils.
Black-eyed Susan – These bright cheery flowers grow quickly in just about any kind of soil.
Northern Dewberry – This plant is attractive to bees, butterflies and/or birds, and self-sows freely.
Texas Sedge – This plant is a good turf substitute for dry to moist shade and is extremely heat-tolerant.
Purple Coneflower – With long-lasting, lavender flowers, this Echinacea plant can handle dry, sandy soil.
Crossvine – This climbing vine produces orange-red, trumpet-shaped flowers, needs little water, and handles cold well.
Creeping Oregon Grape – With holly-like leaves and dark blue edible berries, this plant does well in dry soil and high elevation.
Red Columbine – A beautiful perennial that’s happy in all sorts of tough environments. Attracts hummingbirds and butterflies.
Silver Sagebrush – This hardy plant requires little water and can thrive in rocky soils.
Of course, this list is only a taste of the many native plants that will ensure a successful green roof. For more info, visit the resources below.
Photo: Evan Long/flickr