Dry Weather and Native Plants
This has been a hot, dry, essentially rainless June and much of Minnesota is really feeling the drought conditions. What will July and August bring? Hopefully we will receive some consistent rainfall, but what if this drought continues?
With the unusually dry June, you might have noticed that our lawns and roadside turf areas quickly dried and turned brown. The short roots of the grasses that compose our lawns make them more susceptible to drought. This is because turf grass roots can’t grow and reach down into the cooler, wetter soils deeper down.
So under these conditions, we must water our lawns to keep them green. This lawn watering takes time and energy, is a strain on our water resources, and it still might not be enough to keep that green carpet looking healthy.
One major benefit (out of the many) we often tout about native prairie plants is their drought resistance. This plant community has evolved to handle dry prairie conditions. So what special attributes do they have in order to cope with drought?
Unlike the turf grasses, prairie plants develop long root systems that stretch deep down into the soil, which allows them to reach the lower water table and stay hydrated. While turf grass quickly desiccates and turns brown with little rain, our native plants are still actively growing and blooming, providing critical habitat for birds, bees, butterflies, and a host of other animals.
How deep can these roots grow? Big bluestem (Andropogon gerardii) can grow roots deeper than ten feet. Even the colorful prairie flowers have deep root systems. For instance, purple prairie clover (Dalea purpurea) has a root system that can grow up to six feet. Many native plant root systems aren’t just composed of a long taproot. Many species tout thick, fibrous roots that soak up available water in the surrounding soil like a sponge. These root characteristics allow prairie species to stay lush and green through this hot weather.
Can you think of another adaptation that helps prairie plants live through periods of drought? The answer: it’s about their leaves. Many have thin leaves, which means less surface area for water to evaporate. Other species have hairs along their stem and leaves, which also reduces the amount of moisture that evaporates and is lost to the air. A good example of this is butterfly weed (Asclepias tuberosa) that has relatively small leaves, and is very hairy. Other plants might have waxy leaves that also reduce the loss of moisture and even help reflect heat away from the plant itself.
Another mechanism that prevents plants from losing water has to do with their stomata. This is the name of tiny holes in the underside of leaves where water can evaporate. During hot days these stomata can be closed to reduce the amount of water lost through evapotranspiration. When this happens, a plant might look wilted and have curled leaves, but will recover quickly as temperatures cool or it receives more moisture.
More and more research is going into how plants interact with the microbes in their soils. Some data suggests that these microbe interactions can help plants weather drought conditions. These microbes are mostly made up of bacteria and fungi that help plants take up nutrients and water in exchange for carbohydrates. Plants have adapted to use these microbes to help them grow and stay healthy, meaning healthy soils lead to healthy plants.
Native plants are pretty amazing, as they have evolved and adapted to their local environments. As unpredictable as the weather can be, we love seeing our native plants thrive on the landscape, even during these harsh, dry conditions. While new plantings might need a few waterings during these hot days, once native plants establish we can be confident that they can survive the heat and provide essential food and habitat to our local ecosystems.
Done with the endless watering and trying to keep that turf grass alive? Our retail nursery is chock full of native prairie plants just waiting to add color, beauty, and habitat to your landscape. Go ahead and beat the drought! You will be a guaranteed winner when you use native plants in your landscape.