The many small worlds in your yard

While in college, one of my classes spent a few days in Boxley Valley along the Buffalo National River in Arkansas analyzing the historic site for a design project. Emerging from our tents in the cool morning, desperate for a hot cup of coffee, we saw another tent in the campground was frost covered while ours, under evergreen trees, were not. The pine canopy kept our tents a few degrees warmer and protected from frost.

While studying landscape architecture I heard many lectures on microclimates: South slopes are warmer than north slopes; cold air settles into valleys; morning sun is less harsh than afternoon sun. But seeing and feeling the difference in microclimates within that small campground was a vivid lesson — a few feet in one site can make a difference.
The moment you realize your property is a world of many tiny climatic zones, you instantly become a better gardener. There is a reason the azalea planted in irrigated afternoon shade thrives in your neighbor’s yard, while yours, under the same cluster of pines but baked by afternoon sun and in need of a drink, is stressed. A few feet in a garden can make a life or death difference to a plant, which is why gardeners move plants that do not seem happy.

Our property is at the highest point in our neighborhood, so I hesitate before bringing moisture-loving plants into my garden. Thirsty trees are simply not an option. Buy I refuse to garden without hydrangeas and hostas, which love water and are similarly adored by deer. So I clustered these together under an old pecan tree that I revere. When I ration water during a drought, this area is the last denied our precious well water.
A few feet from the pampered hydrangeas stands a red maple, which claims all available sunlight and moisture from the raised bed around its trunk. Many plants perish in that extreme environment; the proven survivors for such dark, dry, deciduous shade are spring bulbs, epimediums, and columbine.

OK, so let’s take a quick walk around your home and look at typical microclimates. The east side basks in morning sun and afternoon shade. The south side is sunny most of the day. The west side stays shaded in the morning, then roasts under brutal afternoon sun. The north side remains pretty shaded, but suffers from afternoon sun in the hottest part of the year. Sounds simple, but few of us live in a rectangle in the middle of a field. The trees, fences, pavement, moisture, soil composition, wind, and more affect your plants, as do the angles of your home. A windy site may dry foliage. A sheltered area may nurture a plant rated for one zone south (at least for a few winters). I place hydrangeas near downspouts on the east side of the house, which offers both afternoon shade and first dibs on any rainfall. Rosemary thrives in the brutal area under the south eaves where there is plenty of sun and limited rain.

Even the much broader location of Lee County is relative when gardening. A plant that can take full sun in Michigan may not be able to handle full sun in the Southeast. For us “part shade” means morning sun and afternoon shade, while any location that receives three to four hours of afternoon sun, even if it is in the shade until two in the afternoon, is a “full sun” site.
The best way to know your garden is to spend time in it throughout the year, learning where the water flows, where the sun shines at different times of the day and year, and which plants seem happy. To further complicate things, a garden is constantly changing, with trees growing and dying, and changing sun angles. Last year drought-tolerant plants were all anyone wanted to talk about. But weather doesn’t hold still either. Plants suited to a site are the healthiest, and the healthiest plants will best survive weather extremes.

Yes, you can learn about gardening from a book, but the best way to know your garden is to garden in it. You will kill some plants (every gardener does) and move others. You will make mistakes. But you will also find out what works well for you and build on successes. Being aware of the microclimates within your garden will help you be a more successful gardener.