Above Ground Practices
After properly testing, amending and preparing the soil, it is just as important to practice correct horticultural principles and techniques above ground as below ground. Any time even one organic practice or basic gardening principle is implemented, the garden's condition and your odds of success are improved. Don't expect to be perfect, at least right away. As you start gardening correctly and learning more about the soil, plants and your environment, the knowledge and information will fall into place and you will start to think ecologically minded. When faced with a problem, first evaluate gardening practices to determine if the problem was caused by something done or not done. We are more often than not the contributing cause of our gardening problems. There is usually room for improvement in above ground gardening techniques and practices.
Practice No. 7. Micro-niche Gardening
Plant’s survival often depends more on its exact placement in relationship to features surrounding it than to the climate. An example of this can be found close to home at Wildcat Bluff Nature Center, where grasses from the tallgrass, midgrass and shortgrass prairies grow in particular micro-niches best suited to their requirements. Once again, mimicking nature will help us become better gardeners in harmony with nature. Home landscapes have several micro-niches. Micro-niche gardening is nothing more than the old adage, right plant, right location.
A flat plain with uniform soil has one micro-niche. Any landscape containing rocks, boulders, trees, shrubs, fences, buildings, mulch, concrete and diverse soils contain numerous micro-niches. If you plan to landscape your home, you will have areas sheltered or exposed to the wind, some areas in shade, some in sun. South facing brick homes have a microclimate up to a ½ zone warmer (5 degrees) than an exposed site on the north side of the home. Add this to another ½ zone difference for living in the city (as opposed to living in the country). Sloping areas that end in a swale will be moister; soil at the top of mounds will be drier and if amended, provide better drainage for plants that require it. Areas closer to concrete and other heat-reflecting sources will be warmer and drier, as in xeristrips, the area between the sidewalk and street. As a gardener, you will be able to increase your plant palette by thoughtfully placing plants in the proper micro-niche. Thoughtful placement conserves water and lowers maintenance.
If you don't have a desirable micro-niche for a particular plant, create one. In some cases, better placement is just a matter of inches or in using an accent rock to increase survivability. Especially in climates with strong spring winds, such as the High Plains, creating a micro-niche by placing a temporary wind shelter to allow seedlings and immature plants a chance to make it is advisable, often necessary. Temporary wind barriers can be a rock or large board inserted in the ground to shield the plant. Plastic or paper cups with the bottoms cut out are temporary, inexpensive, and quick devices that will protect tender plants from all sides.
Grouping plants together in the landscape according to their water needs is referred to as hydro-zoning. Proper planning of hydro-zones in the landscape is one of the most effective ways to use micro-niches and conserve water. Basically, plants are grouped together in high water, medium water and low water-use zones. All plants need a certain amount of water for survival. This varies from plant to plant, and varies with soil and weather/climate conditions. As you gain experience with your chosen plants, soil and micro niches, you can finesse the placement and spacing of the plants to minimize irrigation maintenance.
Typically, high water-use plants are grouped together close to the water source. Medium water-use plants are placed a little further out and low water-use plants are located the furthest out. There are, of course, native plants that require no irrigation, once established. Hydro-zone these as well, or mix them with low water-use plants and they’ll perform and look better in the garden setting than in nature.
Sloping landscapes offer advantages and challenges. Plan to use it to your advantage, not as a challenge. A slightly sloping yard gathers water at the bottom, a natural planting point for plants requiring more moisture. When the slope ends in a sidewalk or street, the water runs off away from the landscape, unless captured first. The time honored practice of terrace gardening is effective and attractive. The soil in terraced beds, usually better aerated than turf, has a greater ability to soak in rain, greatly lessening runoff. A low water-use border at the bottom of a sloping lawn provides a finished look while capturing runoff, reducing irrigation needs at the same time.
Roof runoff can provide most of the water needs for side plantings. I rarely water the landscaping on the west side of my house, where I’ve put a path, shrubs and ground covers. Our rainfall provides adequate moisture most of the time for my low and medium water-use plants (already established). In times of drought, only a few supplemental irrigations are needed during the growing season.
Just as important as locating plants in the right micro-niche is not placing plants in areas that cause them the most environmental stress. I like to contour beds, in proportion to the surrounding landscape, with low mounds and shallow swales. Doing so creates areas that are drier at the top and moister at the bottom. Place plants that are marginally low water-users at the bottom in the swales where water gathers and drought requiring plants on higher, quick draining ground. This is not only matches the plant with the location, but evens out their irrigation needs.
Some lawn landscapes are contoured to include mounds. Planting high water-use turf grasses on top of drier mounds isn't the best application of micro-niche gardening. Thirsty turf grasses of fescue and blue grass are also high feeders. Inadequately amended soil is rapidly depleted of nutrients by traditional turf. Compound nutrient deficiency with the addition of salt-based fertilizers – heavy clay soils compact and lose ability to drain properly. When lawns are watered, or rain falls, little soaks in, especially on the tops of mounds. Turf quickly thins out and weeds move into bare patches. This scenario is difficult to overcome in high heat and windy locations. In our climate, turf areas that are level perform better.
Shade plants need to be sited in shaded locations, sun plants in the sun. However, in southwest climates where cloud cover is infrequent, plants described as sun loving in English, Northeastern and Pacific Northwest gardening books and magazines will benefit from afternoon shade. In fact, nearly any plant (and gardener) in our climate will benefit from a bit of afternoon shade.
Tender plants transferred from shady locations to direct, relentless sun will need to be eased into their new environment. Set up temporary shades or scrims (temporary micro-niches) to diffuse the light. Wrapping tomato cages with plastic or fabric and covering half hardy plants with plastic tubs, glass dome covers, plastic gallon milk containers with the bottoms cut out and wall-o-waters also creates a greenhouse-like effect.
Greenhouses are nice, but not always practical. We can created greenhouse micro-niches much simpler. It's possible to grow and harvest leafy greens and other cold season vegetables outside during winter, even just under plastic tunnels or fiber frost blankets. Even after the blizzard of February, 2013, lettuce, spinach and other leafy greens are safe and ready to harvest under their protection. The use of temporary row covers, either fabric or plastic, or fabric row covers cut for single plants will greatly extend winter survival.
How does micro-niche gardening fit into a design? Mounds, swales, rocks and boulders suggest a naturalistic style, rather than formal. Formal designs can be achieved with careful plant selection, placement and soil amending. Committing gardening goals and plans to paper fleshes out ideas. Draw the design and walk around the landscape through the day and the seasons to see where beds, borders, patios and paths are natural fits. Pleasantly pondering placement in the landscape is time perfectly spent.