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David Salman, President/
Chief Horticulturist
Ava Salman, Marketing Director
Cindy Bellinger, Editor
Kerry Kirkpatrick, Web Design
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Microclimates: The Mini-zones in Your Garden
By Cindy Bellinger
 Ever notice that the bulbs planted along a south facing wall are the first to come up? Or the locust tree farther out in the yard always loses branches whereas the one closer to the house never does? Microclimates are those areas of varying temperature and weather patterns around your garden, and so often they are the main ingredient to sustaining a wide variety of plants.
It's rare to find a garden with uniform conditions throughout. Some landscape designers even go so far as recommending that you live in a new place for a year before planting. This way you can study the changes in moisture and wind, sun and shade throughout the seasons.
Weather Variables
Climate is the basic factor for diversity among plants and the weather variables that impact your landscape include:
- Temperature; highs, lows, first and last frost dates
- Wind; prevailing wind directions, seasonal variations
- Moisture; seasonal rain and snowfall patterns
- Humidity; or lack of it if you live in the arid western US
Understanding Microclimates
 Think of your whole garden as a composite of smaller gardens; then consider each of these small gardens as a mini-zone. One area might be in the open and so hotter and drier. Another might be against a north wall and be cooler and moister. Then working within each area is the interplay of sun and shade. Each of these different areas will support plants with different growing needs.
When working with microclimates, consider the following--
- Cold air is heavy and dense, it flows down slopes and settles in low-lying areas, getting caught against hedges and fences. Frost is more likely to occur in these areas, which are known as frost pockets. So here, you'd want to plant the hardiest plants, which often means choosing plants for a zone colder than your overall zone site.
- Wind swishes around corners or hurls through openings between trees. Best not to plant in these corridors. Be sure to use heavier mulches in these areas
- Bare ground can lose 20 percent of its temperature when shadows hit it; mulch!
- Hot spots occur anywhere if no shade is available.
- Moist shade occurs under trees or on the north side of fences/buildings. These areas call for plants that are happiest in cooler climates like groundcovers such as
Vinca and Bishop’s Weed. Shrubs that prefer these cooler places are Viburnum and Spiraea.
High Altitude Solutions
 Because of the harsher climates at higher elevations, copying the microclimates that occur naturally in forests is one way to work with the natural elements. High altitude ecosystems typically have four microclimates:
- open and exposed areas (radical temperature swings, lots of wind)
- sunny but wind-sheltered areas (lower heat, less wind)
- deep shaded area (moist soil)
- canopied areas (less moisture and dappled sun)
Opportunities
Each microclimate provides an opportunity to garden in a different way and to use each site to its best advantage. By working with the natural laws of sun, wind, shade and water, any garden will fare much better through all the seasons.
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Creating Microclimates
By Mary Ann Walz
Observation
 This is the key in determining where to create microclimates. In the very early spring, where do you see the first signs of green? Around my house, the very first plants to emerge are the wild mustards and Cheat Grass. Unfortunately, I’m trying to eliminate them but they do tell me where I have hot spots.
I've noticed another hot spot along the edge of the gravel driveway. It's where I first observed
Oenothera caespitosa.
Creating Hot Spots
These areas encourage early growth and can be enhanced for even more warmth.
- Use stone plating--that is lay flat stones (flagstone or slate) nearby to absorb heat. It also warms the soil in the narrow spaces between them.
- A flagstone walkway has hot spots adjacent to those edges that are most exposed to the sun. Bulbs planted here will be the first to emerge.
- Increase the heat and water retention around flagstone by using crusher fines of gravel between the stones.
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Creating Moist Spots
Rocks or gravel not only provide added warmth, they keep soil moist underneath, creating a microclimate that is warmer and moister than the surrounding garden.
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 The north side of a larger rock is cooler than other sides, making life happier for plants that like a little more shade and a cooler, moister root zone. This is the ideal planting spot for
Lewisia x ‘Little Plum.’
- Flagstone walkways are not only warmer in the early spring, they can also have moister soil underneath in the heat of summer making an ideal environment for
Thymus ‘Pink Chintz.’
Other Tricks for Creating Microclimates
- Berm up soil to create hot spots (on south and west side) and cool spots (on north and east side).
- Use a coyote fence to reduce wind and create shade.
- Create a swales and depressions to catch runoff for plants that like more moisture.
- Block harsh sunlit areas with tall brushy shrubs.
- Reduce frost risk with dark stones that absorb heat.
- Reduce heat gain with fences and walls painted white.
Creating microclimates will allow you to extend your growing season and expand your plant palette to include favorites that might not typically be suitable for your zone.
Plant Profile with David's Helpful Hints -- Native Grasses
For a naturally waterwise, low-care lawn or meadow, native grasses are the way to go.
Save Water
 One of the primary objectives of a well planned xeriscape (waterwise) landscape is to limit or eliminate the amount of high-water turf grass. In so many residential and commercial landscapes, Kentucky bluegrass is used as an ornamental ground. Given that this grass requires over 48 inches or more of water (!) during a typical growing season, substituting xeric native grasses like
Buffalo or
Blue Grama results in substantial water savings.
So many xeric designs automatically exclude lawn areas in favor of huge areas of gravel mulch. But this is a huge oversight as native grass lawns are very beautiful and water thrifty.
When irrigating native grass, water infrequently but deeply; put down 1/2" or more of water per irrigation.
Blue Grama is very deep-rooted and doesn't seem to respond to shallow soil moisture, especially in hot weather.
Easy Care
 Maintaining a native grass lawn is a simple matter. During the summer months, irrigation water need only be applied during hot, dry spells. Typically, a deep soaking every two weeks keeps the grass lush and green. Mowing will be infrequent. Monthly cuttings keep it tidy. Mowing it in the fall cutting will let you see your spring-blooming wildflower tulips and crocus. Fertilize Blue Grama once in the fall to encourage strong root growth and fortify the wildflowers and bulbs.
‘Legacy’ and other turf type Buffalo grass cultivars likes more nitrogen and should be fertilized in the fall and again in late spring.
Control weeds in early spring when they are green and the native grass is still dormant. Hand pulling or spot spraying with contact organic or chemical herbicides is recommended.
Best Ways to Plant Native Grasses
Plugs are the most economical way to go when planting Buffalo grass. Buffalo grass seed is very difficult to germinate evenly, and the sod is very expensive. To establish Blue Grama grass, sow seed. It typically germinates quickly and evenly. Blue Grama plugs are best used to mix in with buffalo grass plugs. You can refer to our website’s ‘Gardening Tips’ section for more details on planting and establishing native grass lawns.
Plant Combinations for Great Garden Designs
For a wild splash of color in cooler, shaded areas of your garden try the combination below. The two columbines with the shrub provides a textural element to any garden.
Kerria japonica, Golden Guinea Japanese Kerria is a flowering shrub, especially good in shady areas. The large golden single flowers (the size of a gold coin), appear in mid-spring and repeat sporadically during the summer. In winter the attractive bright green stems add color to an otherwise monochromatic view. Really effective planted around white barked Aspen. Easily grown in average garden soils. Zones 5-8.
Aquilegia species 'Swallowtail'® Seeing Swallowtail® in full flower is a sight you won’t forget. The huge yellow and lemon-yellow bicolor flowers with their 4” long trailing “spurs” are spectacular! The plant is a big, vigorous grower with large blue-green leaves and long sturdy stems that support the huge flowers. Swallowtail® has good heat tolerance and appreciates a compost-enriched garden soil. Regular irrigation will keep the flowers coming. Zones 5-10.
Aquilegia x caerulea Red Hobbit is a delightful addition to the semi-shade border. It's a dwarf with eye-catching red and white flowers. Hybridized from our native Rocky Mt. Columbine, it likes compost-enriched soil with regular irrigation and protection from the afternoon sun. Zones 4-8.
Garden Glossary — terms for the horticulturist.
Perennial: This refers to plants that have soft tissues as opposed to woody stems. These plants also die back to the ground during cold winter months.
Succulents: The loosening of roots when taken from a nursery pot so they won't continue growing in a circle. If tough, they can be cut with a knife. Healthy roots need to stretch out lengthwise.
Xeriscape: Macronutrients are those that are needed by plants in substantial quantities and include nitrogen, phosphorous, sulfur, calcium, magnesium, and potassium. Micronutrients are those that plants need in small quantities and include copper, zinc, iron, manganese, boron, and molybdenum.
Organic: Materials originating from a living organism. In a stricter sense it refers to a method of gardening in which no chemical fertilizers or pesticides are used.
View all the Garden Terminology from our Ezines
More Gardening Articles
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By working with the natural laws of sun, wind, shade and water, any garden will fare much better through all the seasons.
