Why Do Lawns Need Watering but not Prairies?

By Sarah Wilson, MA,
Healthy Planet Staff Writer

Seeing sprinklers watering lawns is so common that most of us don’t give it a thought. Of course, plants need water during hot spells, right? No. Native plants, once established, don’t need our help. They can help themselves.

 Why the difference?

Because most lawn grasses have puny little root systems which only go 6-9 inches deep, while native grass roots can extend downward 6 feet or more. The top few inches of soil our turf grass lives in dries out much faster than the soil many feet below the surface where the native plants find their moisture.

 Also, since those shallow turf-grass roots make no inroads deeper, the water cannot easily penetrate. That leaves excess water simply running off our land and into the street (or a neighbor’s basement.)

 Where-as the deep roots of native plants give water physical channels to soak deeper into the earth, replenishing our natural water resources, and giving native plant roots access to that fresh water for longer. Once your native plants have become established (meaning their roots have penetrated deep into the earth), it is rare that they will ever need watering – even during droughts.

Each of those deep roots do so much more than simply moving and then seeking water. They release glucose and other chemicals to attract and feed the tiny organisms in the soil that the plants need to thrive. Roots farm the land for what they need in ways we do not yet completely understand. And that act of attracting the microbiology they need starts to build the structure of the soil that allows water to be absorbed incredibly efficiently. Our own Missouri Prairie Foundation reports that a healthy prairie can absorb 7 inches of rain in a single storm with no runoff.

Seven inches.

 What if all of us with yards started looking at them in terms of water management and conservation, seeing our plots as a part of the larger water management in our neighborhoods and towns? If each of us started to increase the water absorption potential of our own yards by thoughtfully using deep-rooted native plants, think of what a difference that could make.

 Want to learn more? Here are some excellent local resources.

MSD Project Clear: Rainscaping

Rain Gardening at the Kemper Center for Home Gardening

MIssouri Prairie Foundation Grow Native!: Manage Stormwater