Maximize Xeric Plant Choices with Microclimates

There already are plenty of fabulous choices for drought-tolerant plants, but we found that our choices narrowed a little when we moved into a slightly colder zone. We’re quickly discovering that our new location has a shorter growing season, but that it can get warm here, so unpredictability makes it a little risky but a lot fun.

With microclimates, I figure we can push the envelope on a few of our favorite xeric plants. First, let’s talk about microclimates. In essence, a microclimate is a pocket of an area that can vary in temperature and exposure to the elements. A microclimate can be large or tiny. An example of a large microclimate might be the area that runs along the river. The grass there is still green and the leaves remain on some of the trees. A combination of shelter, shade, lower elevation, and moisture contribute to the cooler temperatures you feel when you walk through there on a sunny day.

river with grass

Microclimates occur along rivers because of dappled shade, lower elevation, and extra groundwater.

Microclimates can be as small as the few feet you have to plant in front of your south-facing wall or the inside of the plastic bottle you place over a seedling to absorb sunshine and maintain humidity for a mini-greenhouse effect.

bottles_micro_web

Tim covered these transplants with cut-off plastic bottles and set them in a window for a mini-greenhouse effect.

We brought a pad from our spineless prickly pear along and to be sure it made it here, we planted it against the rock wall on the northeast side of our garden (facing southwest) to maximize sun and minimize wind exposure. You also can use microclimates to make plants more drought tolerant. For example, put a plant that needs a little more water than nature usually provides in summer where your terrain naturally comes to a slope and slight pool, creating a natural well. And avoid placing a plant that can’t handle drought on a high southwest-facing spot with no protection. In my area, at least, you might as well be putting the plant up on a clothesline to dry before nightfall.

Micro_prickly_web

This transplanted spineless prickly pear is happy in its southwest-facing wall location.

Here are a few more tips for making microclimates work for you and your plants:

  • Try even large trees and shrubs on south-facing walls to add a half-zone of heat. You’ll likely have more success if you buy a plant that’s slightly established (not a bare root, for example). An unusually cold winter might kill the plant or prevent fruiting or blooming, but it’s worth a try.
  • Take advantage of the shade from the heat-loving tree and fill in around the bottom with perennial or annual bedding flowers that need a little bit of cool shade in summer. They might even provide some natural mulch or protection for your tree on cold nights. Columbine is a great example; it’s a gorgeous flower that grows naturally in higher elevation forests, but might thrive under the dappled shade of a landscape tree.
  • Use raised beds and containers to create microclimates. Raised beds that run east to west warm up faster in the spring, and any new vegetables planted on the south side of the beds should beat others to the punch. You can move containers around to create microclimates for plants indoors and out, wintering over cacti and other heat-loving plants in south-facing windows, but setting them out on the patio in spring. Just remember that pots, especially clay ones, dry out more quickly. That’s fine for succulents, but can become a problem for thirsty annuals in the heat of the summer.
  • Use mulch or landscape fabrics and plastic to cover ground or  seedlings, adding some warmth and protection.

Mostly, what works for a friend or neighbor might not work for you and vice versa. Slight variations in elevation and exposure can make big differences to a plant’s health and happiness. But if you’re willing to take a few risks, you might be able to enjoy your favorite plant right outside, or inside, your window.

geranium_web

I’m wintering over a few geraniums. This one loves its location on a south-facing wall right by the window. Notice another transplant behind it with a plastic bag and my dog enjoying a sunny microclimate on the floor to the left…

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