It’s Time for Your Vegetable Garden to Go Native
It’s often presented as an either-or proposition: If you want to conserve water, replace your lawn with drought-tolerant plants or replant some of that turf with a vegetable garden.
But if you’ve ever attempted to keep thirsty food crops alive in a dry, hot California summer—a summer like the one we’re experiencing, one of the driest and hottest on record—it doesn’t take much time holding a running hose to realize that a vegetable garden sucks up plenty of water too. Picking the right varieties of beans, tomatoes, watermelon, and other plants can help cut down on how much you’re sprinkling on the beds. Similarly, working drought-tolerant native plants into the design of your food garden can help conserve even more water—and make your yard more productive. Instead of either-or, why not both?
The edges of my backyard are dominated by plants that I rarely, if ever, have to water—perennials such as white sage and annual wildflowers such as the California poppy, our state flower. The passive maintenance and plentiful blooms make these plants an easy, beautiful addition to my yard, and they draw a lot of bees and other pollinators. But after reading Dan Barber’s new book, The Third Plate, in which he spends an almost inordinate amount of time talking about how crop rotations create healthy soil, I became mildly obsessed with figuring out ways to create a more harmonious, beneficial relationship with my vegetable garden and native landscaping.
Barber writes about a farmer in upstate New York, Klaas Martens, who plants a series of soil-enriching crops in advance of the heirloom wheat that drew Barber, the chef at the farm-to-table restaurant Blue Hill, to his farm. Buckwheat and clover are two of those crops, as are other legumes, which have the unique ability to transfer nitrogen—vital to plant growth—from the air into the soil.
It just so happens that perennial buckwheat, a cousin of the annual crop grown for its grain-like seed, is one of the dominant plants in the Southern California landscape. A native clover grows here too, as well as plenty of other nitrogen-fixing perennials—plants that not only add fertility to the soil but attract a host of bees, moths, butterflies, and hummingbirds. Instead of trying to re-create the intricate series of crop rotations Martens practices on a far smaller scale, why not reimagine them in a more stationary, California-centric manner?
After a wildfire leaves an area cleared out, some of the first plants to emerge from the charred earth are lupines, which are legumes (think beans and peas) that, in addition to having beautiful spikes of pale-blue flowers, help encourage more plants to grow with the nitrogen they add to the soil. Annual arroyo lupine could be similarly employed in a garden, used as a soil-enriching cover crop in late winter and spring, preparing a plot for summer’s tomatoes or other warm-season vegetables. Not only does it add fertility, but lupine has deep roots that break up compacted soil, improving drainage and water retention.
There are perennial lupine species too, such as silver bush lupine, which add nitrogen, attract pollinators, and send roots farther into the dirt year after year. Planted in between fruit trees or next to garden beds that won’t be receiving too much water in the dry summer months—if watered like you water thirsty lettuce, they won’t only fail to thrive but will likely die—a plant like silver bush lupine can contribute to your garden both above and below ground.
For buckwheat, the prospects are somewhat different, as the cover crop only pays off when the plant is turned back into the soil, releasing nutrients such as phosphorus as it decomposes. For slower-growing, long-living perennial varieties, it doesn’t make sense to grow them from seed and turn them back into the dirt over the course of a few months. That’s not to say they can’t help support a vegetable garden. The popcorn-like clusters of flowers, varying from white to pinkish-red depending on the variety of buckwheat, bloom in the summer months, long after the wildflower explosion of wetter spring. Not only do they help draw in native pollinators once the rains go away, but the flowers last, staying on the plant throughout the summer and into the fall, turning a dark red-brown as the weather cools. They can pull in bugs to help pollinate an entire growing season’s worth of crops and need little water to do so. The same can’t be said for a border planting of marigolds or nasturtiums.