Spring is here, and it’s time to start thinking about landscaping. Generally, the more elaborate a landscape design and its plantings, the more maintenance is required. Annual efforts must be made to ensure that proper care, pruning, fertilizing, and fall cleanup of the landscaped areas occur.
Watering, or irrigation, is the most essential element for growth. The goal is to supply water before plants show signs of wilting, yet to not overwater, because wet soil restricts root development. The top inch of soil should be dry before plants are watered again, and then enough water should be applied to penetrate deeply.
Remember to coordinate watering plans with local codes and regulations. Regional and community water restrictions are common and have forced planners to rethink landscape design. Landscaping with native plants that need minimal water—xeriscaping—is the current trend. Irrigation costs can also be significantly reduced by using a separate meter for irrigation needs.
Time of Watering
Water is best supplied to plants in the early morning, before the sun is high, because the sun will burn wet foliage. Another reason to water in early morning is to minimize foliage diseases; water that has not evaporated from foliage by nightfall encourages the development of powdery mildew and other fungi. Watering during midday is inefficient because much of the water is quickly lost to evaporation.
If temperature, humidity, wind, and day length never varied, a garden could be watered according to a calendar schedule. Weather conditions, however, will upset such a schedule. Under the influence of a hot, dry wind, plants use water so rapidly that shallow-rooted plants cannot absorb water from the soil fast enough to prevent wilting. In such weather, watering must be more frequent than a timed schedule would suggest. Conversely, when coolness or humidity prevails, watering should be done less frequently.
The sources of available irrigation water should be carefully evaluated as a part of landscape planning. Primary water sources include municipal systems, private wells, and reclaimed systems.
Small landscapes typically rely on municipal water systems for irrigation. This water usage might be subject to local sewage charges, making it cost-prohibitive for larger landscapes. In such cases, the availability of water service through an additional water meter designated only for irrigation might be available and may be more cost effective.
Property managers with large landscapes should consider installing a private well. Although the initial cost is high, lifecycle costing may show substantial savings in future years, especially if irrigation water is subject to sewer charges. A possible drawback to private wells is the high mineral content of some well water. In such areas, irrigation water may stain buildings and walkways, creating additional maintenance problems.
As a result of water conservation and water quality developments, many areas are developing reclaimed water systems. Some systems deliver highly treated sewage effluent as irrigation water, while other systems use reclaimed water (other than gray water) to irrigate.
The nutrients most essential for plant growth are nitrogen, phosphorus, and potassium. The label on a container of fertilizer indicates the proportion of each of the three vital nutrients in the fertilizer: for example, 5 parts nitrogen to 20 parts phosphorus to 10 parts potassium is written as 5:20:10. A complete fertilizer contains all three of these primary nutrient elements. The higher the numbers are in the ratio, the more concentrated the fertilizer; for example, a 48:0:0 formula contains twice as much nitrogen as a 24:0:0 fertilizer.
It is important to have a soil test done to determine the rate of fertilizer to apply. Additionally, many local laws and codes may restrict the use of phosphorus-containing fertilizers—especially around lakes and streams.
Nitrogen is the most important nutrient for plants and is most quickly used up from the soil. Phosphorus and potassium are naturally present in soil minerals; however, because they are not in a state readily available to plants, supplementary feedings are often necessary. Other nutrients may also be needed.
Nitrogen: The first percentage listed on a fertilizer label is nitrogen. The basic functions of nitrogen are to stimulate plant growth and chlorophyll production, or greenness.
Phosphorus: The second percentage listed on a fertilizer label indicates how much phosphorus the mixture contains. The primary functions of phosphorus are to stimulate the development of the reproductive parts of plants (buds, blossoms, and seeds), improve root development, and provide disease resistance.
Potassium: The third percentage listed on a fertilizer label is potassium. Plants need potassium to develop hardiness and resistance to cold and drought, stimulate disease resistance, and encourage root development.
Other Nutrients: Other elements, such as calcium, magnesium, sulfur, iron, zinc, and manganese, are also important nutrients for plant growth.
Application of Fertilizers
Fertilizers are available in liquid and granular forms.
Liquid fertilizers are easy to use and available in different formulations. The nutrients are supplied to plants immediately, and there is little chance of burning a plant when following label directions. Many gardeners apply liquid fertilizers at half the recommended amount, but at twice the recommended frequency, so that plants will receive a steadier supply of nutrients.
Granular or pelletized fertilizers are formulated to release their nutrients at a steady rate over a longer period. These slow-release fertilizers are the most widely used. Granular fertilizers are more practical than liquid fertilizers for large-scale use because of their lower cost and less frequent application.
Mulch is a surface covering that can contain many different materials. Common, natural mulch materials include decomposing leaves, bark, or pine needles.
Mulching keeps the soil cooler and wetter in summer and warmer in winter. This covering protects roots from stress during temperature extremes. Mulches improve soil composition, as the mulch materials break down and are incorporated into the soil. Mulching also provides an aesthetic benefit, making planting beds more attractive and inhibiting the germination of weeds.
Weeds are undesirable plants aggressively competing with the desirable ones. Some weeds are peculiar to a given location because of climate or special soils. Keeping weeds from lawns, flower beds, and shrub beds is desirable, but can be difficult.
Transfers of seeds by wind, birds, and mowers are the most common methods of spreading weeds. A landscape area located next to idle or poorly maintained land where weeds flourish will become infested from airborne seed. Weed seeds are noted for their length of dormancy: they might remain in the soil for many years just waiting for the right conditions to germinate.
Manual Weed Control
The manual approach to weed control involves simply pulling weeds by hand or hoeing or cultivating. This approach is effective for lawn areas and shrub and flower beds when the area is small. Covering beds with organic mulches after weeding will help prevent new weeds.
Although the manual approach to weed control is labor intensive, it is the safest approach with no impact to surrounding plantings. In large areas, in which weed pulling becomes impractical, chemical herbicides must be used.
Chemical Weed Control
Herbicides are chemical weed killers used to reduce the time spent hoeing, pulling weeds, or cultivating large areas. Because weed killers used improperly can damage valuable plants, the product label instructions should always be read carefully before any such product is used.
Herbicides and pesticides should be stored in locked and ventilated areas. Handlers of such chemicals should undergo proper training and wear protective equipment. Local regulations may require training for maintenance personnel who use herbicides. Areas treated should always be marked to inform people to stay clear of the treated area. All relevant material safety data sheets should be kept on-site.
This article is adapted from BOMI International’s course The Design, Maintenance, and Operations of Building Systems, Part II, part of the RPA and FMA designation programs. More information regarding this course or the new High-Performance certificate courses is available by calling 1-800-235-2664. Visit BOMI International’s website, www.bomi.org.