Dealing with Drought

As our local population increases, water availability is becoming an issue of great concern. While we often have ample rainfall, the storage capacity of our local reservoirs has not changed. Mandatory outdoor watering restrictions have been in place for several years and these restrictions won't be eliminated any time soon. As a result, our landscapes often take it on the chin. It stands to reason that if you want to have a nice looking landscape and conserve water, certain landscape changes are in order.

The term xeriscaping (dry landscaping) became part of our vocabulary several decades ago in the western states. Faced with extreme droughts and often total watering bans, creative gardeners adapted. Loosely applied, xeriscaping means using techniques and plants that do not need more water than is supplied by precipitation. This varies from places like Phoenix, with less than 10 inches of annual rainfall, to Atlanta with an annual rainfall of 50-55 inches.

Creating a Xeriscape:

*Use locally native plants whenever possible. These plants have spent eons adapting to the local soil and climate. There are also many suitable non-native plants from similar climates.
*Group plants together based on their water requirements. Place those needing the most water closest to a source of irrigation.
*Site plants based upon needed sun exposure and soil. Install the plants correctly by adding organic matter to the soil and monitor them until they are established, which can take from 1-3 years, depending upon the species and size.
*Use a 2-3 inch layer of organic (not synthetic) mulch and replenish (not replace) it 1-2 times each year.
*Reduce or eliminate turf, especially thirsty turf like Fescue.
*Reduce fertilizer use during dry periods, especially those high in Nitrogen
*Install a rain gauge and water deeply only when needed.

When it becomes necessary to irrigate your landscape, which methods are the most effective, timesaving and cost efficient? This will depend upon the size of your landscape, the plants and the amount of time and money you wish to spend.

Automatic Sprinklers:

Without a doubt, this is a very convenient method of irrigation. You can set the timer and forget it. Automatic sprinklers can cost thousands of dollars, especially if you have multiple zones and a large landscape. There are drawbacks. Automatic sprinklers will run as set whether your landscape needs irrigation or not. I've seen sprinklers running during a downpour. They also can be very inefficient, losing as much as 50% of the water to evaporation. Many systems are also set incorrectly and water the landscape too frequently and for too short a time period leaving plants susceptible to diseases and shallow, drought-prone roots. My advice is to turn the timer off and manually start the system only when you need to water. The system should run only once or twice a week (if it's really dry) and only long enough to put one inch of water on the landscape. Use a tuna fish or cat food can to determine the needed duration. Water in the early morning to reduce loss to evaporation.

Drip Irrigation Systems:

Drip systems deliver water directly to the root zone of plants, either individually or in small groups. Like automatic sprinklers, these can be set to timers. Above ground tubing is run through the landscape and each plant has its own head that connects to the main tube. Usually all tubing is concealed below a layer of mulch. The amount of water delivered to each plant can be individually set based upon the plant's needs. This is one of the most efficient irrigation systems since water is delivered directly to the plant and very little evaporates. The drawbacks are that it can be expensive and time consuming to install. Somewhat complicated calculations are needed to set the system for the correct amount of irrigation. If you make changes to your landscape (transplanting or installing new plants), you have to change the irrigation system. Drip systems are not designed to irrigate turf areas and you have to remember to turn the system off if there has been sufficient rainfall.

Soaker Hoses:

I refer to soaker hoses as the poor man's drip irrigation system. I will say that this is my favorite system of irrigation. Porous hoses are “snaked” through the landscape around the base of plants and covered with mulch. Water drips slowly from the hose directly to the ground. Little is lost to evaporation. Soaker hoses are inexpensive and easy to install. If you make landscape changes, simply reposition the hose. The drawbacks are that they must be attached to a spigot with a standard hose and are usually manually run (although I've seen crafty gardeners devise timer systems). They are not designed to irrigate turf areas. You will also need to calculate how long to run the hose to deliver the desired amount of water. Since they uniformly distribute water over the entire length, this is where the practice of grouping plants together based upon water needs becomes important.

Hand Watering:

Watering by hand is still a good way to make sure that the correct amount of water is given to each plant, but it's very time consuming. Still some gardeners enjoy the task as it also gives them the chance to visually inspect plants and deal with potential problems early. Once again, only water once or twice a week and in the early morning.

How Much Water?

Simply put, if your landscape receives an inch of water per week over the entire area (either by irrigation or rainfall) that's plenty for most plants. For individual plants, four gallons per foot of height per week is usually sufficient.

Watering Restrictions:

Mandatory watering restrictions are in place and are always subject to change. Currently, we are on an odd/even address system.

Odd-numbered Addresses: Tuesdays, Thursdays and Sundays
Even-numbered Addresses: Mondays, Wednesdays and Saturdays
No outdoor watering on Fridays

Hourly restrictions vary from county to county and some are on total outdoor watering bans. To keep up to date with the restrictions that apply to you, visit this web site or call your municipal water company.

Tough Choices

Should we face a severe drought and increased watering bans, you may have to make tough choices on what lives and dies in your landscape:

Lawns and Annuals: These should be the first you let die. Lawns and annuals are easily replaced and don't take long to mature.

Perennials: These should be next on the list of things to let go. Many have the ability to go dormant in extreme conditions. They can also be cut back early if drought conditions are severe and prolonged. They are also easily replaced and mature quickly.

Trees and Shrubs: Every effort should be made to save your trees and shrubs since they are the most expensive to replace and take the longest to mature. If the drought is severe and prolonged, cut back shrubs to reduce the moisture being lost through the leaves. However, do this almost as a last resort.

Total Watering Bans

If your are facing a total outdoor watering ban, there are still some things you can do to save your landscape:

*Increase the amount of mulch in your landscape up to 4-6 inches.
*Use gray water (see below) to spot water your most precious trees and shrubs.
*You may need to cut back perennials and shrubs to reduce the amount of moisture being lost.

Gray Water

Gray water is essentially water that has been used but not purified yet through a waste treatment plant. It is legal to use gray water in most instances. Sources of gray water can include:

*Condensation from your air conditioning unit. This is distilled water and perfectly safe to use.
*Rain water collected in barrels.
*Water from the bath, shower, sink, dishwasher or washing machine. Most soaps and detergents will not be in concentrations high enough to cause most landscape plants problems.


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