Native Plants: Planting in Dry Soils
Dry site conditions can offer a challenge to traditional gardeners, often requiring soil amendments and constant upkeep while yielding unsatisfactory results.
Luckily, there are many plant species native to North America that have evolved to thrive in dry conditions, each with its unique ecological and aesthetic characteristics. Making informed decisions when choosing a planting’s composition can result in beautiful, robust gardens which, once established, require little or no maintenance and can support a diverse array of native wildlife. These gardens can be short or tall, traditional, modern, or naturalistic depending on which species are selected and how they are used.
Many factors affect soil moisture including soil texture, rock and gravel content, topography, and exposure to sun and wind, among others. Soil texture is the relative proportions of sand, silt, and clay in the soil. Sand is the most permeable, and therefore driest, due to its large size and angular geometry, whereas clay is the least permeable, and wettest, because of its small size and plate-like shape. You can usually get a good sense of your soil’s texture just by rubbing some of it between your fingers: sandier soils tend to feel gritty while soils with more silt and clay tend to feel smooth. Rocks and gravel, like sand, will increase a soil’s drainage, leading to drier conditions. The tops and faces of slopes hold less water due to surface runoff while valleys and flat areas hold more water. Finally, soils that are very exposed to sun and wind will tend to be drier than those that are densely shaded and protected from wind. Overall, sites with dry soil will rarely experience standing water and are more susceptible to drought.
Native drought-resistant species are able to thrive in dry conditions due to various adaptive traits they have acquired throughout their evolutionary history within their regional environments. For example, many native prairie species possess tap roots that can reach more than ten feet underground, allowing them to access water from deeper soil layers. Other species possess complex, fibrous root systems that allow them to capture moisture more efficiently. Additionally, many native drought-resistant species have other physical traits that increase their ability to retain moisture, such as fine hairs, waxy cuticles, and the ability to close their stomata during drought periods. Compared to their nonnative counterparts, native drought-resistant species exhibit lower transpiration rates and increased water storage capabilities. With such a wonderfully diverse native flora, gardeners need not choose between beauty and utility– there is always a native solution to meet your needs.
