The Amazing Adaptability of Native Plants
By: Anna Lindquist, Garden Lead and Native Plant Specialist | 05/02/2019
Imagine being stuck in one spot, subject to the elements, reliant upon the kindness of strangers to feed you, and unable to defend yourself should something decide to take a bite out of you…
This is the life of a plant, and for our local flora, life is especially harsh in our near desert climate where resources are scarce. Luckily, after years of evolution, the plant palette you will encounter on a hike in the Boise foothills is made up of species which have excellently adapted to our climate through a variety of traits.
Starting from the ground up, plants like our native bunch grasses have developed deep root systems. This is in contrast to annual, non-native grasses such as cheat grass, which has very shallow roots, and thus is easily pulled out of the ground. Sagebrush also has deep roots, or rather a double root system comprised of shallow roots near the surface, and a deep taproot that extends up to ten feet down. This taproot is able to access water the shallow roots cannot, and acts as a straw, bringing up water for the shallow roots when they need it. Moving up into the leaves of the plant, we can find a diversity of adaptations as well. The small leaves of our three main foothills shrubs, sagebrush, bitterbrush, and rabbitbrush, mean that they have a reduced surface area. Just like us, plants lose water when exposed to sunlight, so this reduced surface area, often coupled with curved leaves, means that the plant can get enough sunlight to photosynthesize, but is not revealing anymore of itself than necessary. The color of the leaves themselves can also be an indicator that they plant has adapted to drier conditions. Many of our natives, such as sagebrush, balsamroot, and pussytoes have gray leaves, which compared to dark green is much better at reflecting sunlight. Moving in closer to the leaves, you may also notice tiny hairs. Leaf pubescence—aka hairiness—also helps to reflect sunlight, as well as create a microclimate around the leaf stomata that keep it cooler than the ambient air. Native plants that aren’t gray, like Cercocarpus ledifolius¸ Curl-leaf Mountain Mahogany, have sclerophyllous leaves, meaning all the stomata are on the underside of its thick, evergreen leaves, further reducing its transpiration loss. And if all of these adaptations fail, native plants have one last trick in their book—dormancy. A number of our local flora simply call it quits when it gets too hot, such as the balsamroot we see blooming now; in a few weeks it will set seed and then die back to the ground to wait out the heat of summer, surviving on the water it can access with its taproot.
For more information on our native plants and how to incorporate them into your home garden, our class—Summer Survivors—will take you around the garden to see these wonderful plants in action! Look for registration information on our website soon.