I am new to the Garden Bloggers Design Workshop on Gardening Gone Wild, but I was moved by this month's topic, Water-Wise Gardening, because it is an issue close to my heart. Nancy's post raises a great point: xeriscaping can go beyond cacti and gravel in desert environments, which is the usual conception of that term. Here in northern Illinois we are certainly not in a desert, but that doesn't mean we can be careless with our water resources. Rainfall can be unpredictable here in more ways than one.
The short- and tallgrass prairies that evolved in Illinois after the last Ice Age were composed of extremely drought-tolerant plants, and with good reason. As any resident will remember from last fall, we can have deluges and flooding that now result in losing large amounts of rainfall as runoff and wasted stormwater. Conversely, we experience periods of intense drought when our clay soil becomes a parched brick. (Remember the summer of 2005? How about 1988?) These inconsistencies have been occurring since long before corn fields and urban sprawl consumed the prairies, so the native grasses and forbs developed huge root systems to deal with them. When the floods come, those roots store extra water for use when the rains stop. And if the drought is bad enough to exhaust that supply, the 6-foot, 8-foot, and 10-foot root systems can reach the water table underground.
What does this matter for water-wise gardening? Personally, this information helped convince me that restoring native landscapes is crucial to the health of our gardens, our soil, and our overall environment. Growing the bluestems, prairie dropseed, asters, baptisias, and the like means that gardeners don't have to water their gardens regularly, if at all. You've all heard me sing the praises of Canadian columbine for this very trait, and my asters, goldenrod, and coreopsis, to name a few, enjoy the same drought-tolerance.
On the other side of that coin, my great blue lobelia (L. siphilitica) and Joe-Pye weed help soak up the water that puddles in a certain low spot in my front garden. I'm planting a rain garden this spring in a part of my back yard that is particularly prone to flooding. The sedges, cardinal flower (L. cardinalis), swamp milkweed (Asclepias incarnata), and other natives going there will use those fabulous roots to keep runoff from reaching our storm sewer.
This is an important benefit of prairie and savanna plants: they save water when it's around and go without it when it's scarce. Growing these types of plants is a water-saving gardening technique, and that is the definition of xeriscaping. This attribute definitely changed my gardening habits because I wanted to conserve water, and like Nancy said in her post, I wanted to make my life easier too. I try to explain this benefit to other gardeners in the hope that they will plant some natives, which can contribute to the broader health of our water resources. They may not be the yuccas that one pictures upon hearing the word "xeriscape," but many prairie plants can be just as important to wise water use in the Midwest!