Xeriscaping is a word being thrown around often these days with the continuing drought and water-shortage issues facing the area. With conversations I have been a part of recently, and in listening to the conversations of others, it is obvious the word or the concept can be a source of confusion in some instances. I will try my best to explain what xeriscaping truly means and hopefully eliminate some of the confusion.
Xeriscaping is a word coined by the Denver Water Department several decades ago to describe landscaping with water conservation as a main objective. The word is derived from the Greek "xeros," meaning dry, and landscaping -- thus, xeriscaping. Xeriscaping is not a specific "look" or a particular group of plants; it actually is a combination of seven gardening principles that maximize water efficiency while creating an attractive landscape at the same time.
Steps required to create a true xeriscape:
Planning and design
Planning is essential in creating a sustainable, attractive xeriscape. Take into consideration site characteristics that affect water use (i.e. slopes, exposures, micro-climates) and then design the area with these things in mind. Put it on paper. A scale drawing or diagram can go a long way in helping visualize what your xeriscape might look like. Group plants according to water use, and take into account mature plant size.
"Take care of the roots, and the tops will grow themselves." That phrase has been used to describe soil's importance in plant growth. A healthy soil will result in healthier root systems which, in turn, create a more drought-tolerant landscape. Amending entire garden beds (not just planting holes) with organic matter such as compost can help loosen heavy, clay soils, allowing moisture and nutrients to infiltrate more readily to the roots versus running off. On the other hand, adding organic matter to sandy soils will help increase the soil's water holding capacity versus water loss due to leaching below the root zone.
Water deeply and infrequently to encourage deep, more drought-tolerant roots. Only water when absolutely necessary. Turfgrass should be watered to a depth of at least 6 to 8 inches, while flowers and gardens should be watered to a depth of at least 8 to 12 inches. Trees and shrubs need to be watered to a depth of 12 to 18 inches, as that is where the bulk of the roots are located. Watering much deeper than these depths is a waste of water. Check watering depth by using a probe (i.e. long screwdriver, piece of rebar, strong wire, etc.). When the probe hits resistance, you likely have hit dry soil. This is the depth to which the moisture has reached.
Drip or sub-surface irrigation is the most efficient method, as it places the water exactly where you need it. If watering with sprinkler systems or by hand, irrigate early in the morning to take advantage of lower wind speeds (hopefully), less evaporation and higher humidity levels. Watering at this time of day also allows plant leaves to dry quickly.
The need for supplemental irrigation is reduced when organic mulches properly are applied around plants. Examples of organic mulches include wood chips, cedar mulch, straw, leaves, cottonseed hulls, etc. These mulches decrease soil temperatures in the heat of summer while limiting evaporation from the soil surface. Organic mulch also discourages weed growth and breaks down over time, helping to improve the condition of the soil (see soil preparation). Generally, a 2- to 4-inch layer of organic mulch is ideal in most situations.
Inorganic mulches, such as gravel, generally are not recommended for use around plants as they can create a hotter, harsher environment for plant roots. Organic mulches are preferred for use around plants in our area.
Right plant, right place
An extremely important step of xeriscaping is to plant the right plant in the right place. Plants vary in the amount of moisture they require, so it is critical to know what those requirements are. Additionally, different areas of the yard might receive different amounts of moisture, sunlight and wind. Take this into consideration when choosing plants for the xeriscape. Group or zone plants with similar water requirements together. For example, group a crab apple tree with shrub roses in a planting bed versus planting the trees and shrubs sporadically throughout a turf-grass area. Since trees and shrubs need to be watered differently than turf, planting them in separate zones will allow for more efficient watering and healthier plants.
Select low-water use or drought-tolerant plants if possible.
Practical turf areas
Cool-season turf grass, such as fescue or Kentucky bluegrass, typically require the most water and maintenance in the landscape. Limit cool-season turf areas. Consider using mulches, ground covers, ornamental or native grasses, shrub beds, decks or patios instead. Avoid odd-shaped or narrow strips of turf grass as these can be difficult to irrigate and might result in wasted water.
If you have full sun, consider planting warm-season turf grasses such as buffalo and Bermuda grass. These warm-season grasses are well-suited to our area and, once established, will require little supplemental irrigation (if any) in comparison to the cool-season grasses.
Keep areas designated to turf grass practical for your use. Do you really need that vast expanse of green grass in the front yard?
While xeric landscapes can be low-maintenance, they still will require some degree of care throughout the year. At appropriate times, proper pruning, mowing, weeding, fertilizing, watering, and insect and disease control are important to maintain the health of your xeriscape.
Overall, these steps create a true xeriscape. As you can see, it is not just about rocks. Reducing outdoor water use does not have to mean replacing lawns and trees with plastic and gravel, or turning flower gardens into cactus gardens.
Holly Dickman is Ellis County Horticulture Extension agent.