Have you ever fallen in love with a particular plant in your neighborhood, tried to grow it yourself (maybe more than once) only to watch it die, or just not thrive? What the heck? You and your neighbor are in the same foothill climate zone, right? And let’s say you know you didn’t underwater or overwater it, nor did the plant display any signs of insect infestations or damage from disease. It just seemed to have, well, faded away.
The problem—and solution—might lie in a microclimate in your garden. Microclimates are areas of your landscape that might be cooler, warmer, wetter, drier, or more or less affected by winds, due to topography, structures, and orientation to the sun. These variables in your garden can make a big difference to plants. So before you give up on those wished for peonies, California lilacs or any other plant, consider how you can use microclimates to your advantage.
Highs and Lows. We all know that cold air sinks and hot air rises. But how often do gardeners actually take this into consideration when positioning a new plant in the yard? If you live in a valley, or if you have a garden at the bottom of an incline, remember that those lower areas are going to experience colder temperatures in general, and will be more susceptible to frost damage than areas on higher ground. Plants that cannot tolerate the colder extremes might make it in a more elevated spot.
Sun Exposure. If a dearly beloved plant isn’t doing well on the north side of your house, try moving it to the sunnier, warmer south or east side. And the converse is true: If a plant is wilting from the heat of your hilltop home, consider moving it to the cooler north side, or under an eve or pergola that will provide added protection from the sun.
Winds. This might be the most difficult microclimate to deal with. If there is a pocket in your yard that consistently experiences wind that is damaging plants, think about planting or creating barriers, such as larger bushes, fencing or rock walls.
Structures. You can create a warmer, sunnier microclimate by positioning a plant next to a highly reflective surface, such as a light-colored house or fence. The light and heat generated from structures can provide just what a plant needs to thrive in an otherwise dicey location.
Raised Beds and Terraces. Like hilltops and hillside slopes, raised beds, terraces, decks and roofs can warm and drain earlier in spring, especially if they are oriented toward the south.
Hardscape. Pavement, stone paths and rock walls absorb an enormous amount of heat and radiate it back to the surrounding landscape, which can be good news and bad news. In the hottest summer months, in areas not shaded by trees, plants situated next to hardscape can fry if they aren’t heat lovers. On the other hand, that same hardscape will radiate heat into the night, which can protect plants that do not like chilly evenings.
Next time you spend time in your garden (or garden-to-be), keep an eye out for how you can use microclimates to create the landscape of your dreams.
Rachel Oppedahl is a University of California Cooperative Extension Master Gardener of Tuolumne County.