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Efficient irrigation-landscaping-Conservation Corner aspects of sustainable landscaping can help you ensure the success of your project. Photo: Water Authority landscape professional

Efficient Irrigation Delivers Water While Protecting Plants

Due to the lack of rainfall in the San Diego region, even sustainable landscaping sometimes relies on artificial irrigation. Irrigation systems must be thoughtfully designed, installed, and programmed. Once in place, the many interconnected mechanical elements must be maintained properly for optimal performance.

“Irrigation efficiency” is a way of describing how well your irrigation system is doing its job delivering water for the beneficial use of the plants in your landscaping.

When irrigation system efficiency isn’t maximized, it can cause you to use more water than needed. Possible problems fall in three major categories: site conditions in your landscaping, irrigation control, and the uniform distribution of water by your irrigation system.

How to maximize irrigation impact

You may want to get help planning your irrigation system from a qualified professional. Photo: San Diego County Water Authority

There are three ways to improve your irrigation system efficiency:

  • Smart Irrigation Management
  • State of the Art System Upgrades
  • Matching Irrigation to Your Hydrozones

Setting and forgetting your irrigation controller is a thing of the past. Even if you don’t have a “smart” irrigation controller to adjust your program for weather conditions, be more proactive in managing your watering, and more closely try to match your watering schedule with the actual water needs of your landscaping.

Upgrading your system with state-of-the-art components is a good investment and the single most significant thing you can do to save water.

Tips on professional help

You may decide to get professional help with your irrigation system. Look for designers or contractors qualified to provide these services. Credentials such as the Irrigation Association’s Certified Irrigation Designer designation can help assure your project will be successful. You can also ask if your contractor is a Qualified Water Efficient Landscaper (QWEL).

This article is part of a year-long series inspired by the 71-page Sustainable Landscapes Program guidebook. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org.

Native plants-New landscaping-room to grow-plants-watersmart living landscape

Provide Room to Grow in Your Sustainable Landscape Plan

Note the height and width of plant species when they mature when choosing plants for new sustainable landscapes. Proper plant placement, taking into account the mature plant’s size, will limit the need for regular pruning, and reduce the amount of maintenance required over time.

While regular pruning and removal of dead plant materials is vital in our region for wildfire prevention, overly aggressive pruning harms plant health and doesn’t allow natural shapes to emerge.

Use the following spacing chart to help you figure out how many plants you need per square foot, based on the mature size of the plants.

Space plants on your landscaping plan at their full mature size, not the size when you first plant them. Graphic: Water Authority

Space plants on your landscaping plan at their full mature size, not the size when you first plant them. Graphic: San Diego County Water Authority

Scale your plants at maturity

On your landscaping plan, use circles to note the size of every plant at maturity using a one-inch to four-foot scale. Use colored pencils to denote different water needs of the plants selected. It will make it easier to group plants into their proper irrigation zones (hydrozones).

Wide canopy trees that grow to 20 or 30 feet in diameter will significantly change the landscaping over time. Will this change the microclimates in the future? Consider whether a tree will cover a large section of landscaping with shade that is currently getting full sun. If plants that thrive in full sun are eventually covered in shade, the landscaping may need to be updated in time.

Small but mighty

Planning for the amount of space your new plants will need when fully grown will help your landscape thrive. Photo: Sweetwater Authority

Planning for the amount of space your new plants will need when fully grown will help your landscape thrive. Photo: Sweetwater Authority

Select the smallest, healthiest plants possible, especially when choosing native plants. Once they are planted in properly prepared soil and watered wisely, small plants establish themselves more vigorously than plants raised in larger containers. Do not plant more than the space allows when the plants mature.

Root depth matters

Take note of the root depth of plants when they are placed into the landscaping. Note the root depth on the plan. Trees will be irrigated less frequently, but for a longer period of time. Groundcovers with shallower roots require more frequent, shorter periods of irrigation. Keep these types of plants on separate hydrozones. Learn more about hydrozones

This article is part of a year-long series inspired by the 71-page Sustainable Landscapes Program guidebook. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org.

Hydrozones-Conservation Corner-landscaping

Know the Hydrozone Game Rules

Hydrozones are the different areas of your landscaping where plants with similar irrigation needs are grouped together.  This allows you to apply water as efficiently as possible through rainwater catchment, supplemented by irrigation, while avoiding unnecessary and wasteful overwatering.

Sun exposure, slopes, and plant root depths need to be taken into consideration along with plant water needs. All these characteristics create specific hydrozones. Even when the soil is the same, a full sun area is one hydrozone, full shade areas are another, and mixed exposure areas create yet a third. Shade from buildings or trees can also raise or lower temperatures.

Each irrigation valve should water its own separate hydrozone populated by plants with similar water needs, living conditions, and root depths. Plants with high water needs such as vegetables or lawns need to be grouped into their own hydrozone. Sprinklers or emitters on this zone shouldn’t overwater anything else.

Don’t overdo it with your irrigation

Inspect your sprinkler heads regularly to make sure they are not obstructed or watering onto pavement or other hardscapes. Photo: Irrigation Association

Inspect your sprinkler heads regularly to make sure they are not obstructed or watering onto the pavement or other hardscapes. Photo: Irrigation Association

Each hydrozone must be able to handle enough water volume for every emitter to work properly. Hydrozones should have individual sprinklers or emitters delivering only the required amount of water, spaced out so every plant in the hydrozone receives an equal and accurate amount. If two sprinklers cross over one another, plants receiving water from both will receive more water than needed. In this example, sprinklers should be turned away from each other, or be reset farther apart. Professional landscapers call this “matched precipitation.” 

This article is part of a year-long series inspired by the 71-page Sustainable Landscapes Program guidebook available at SustainableLandscapesSD.org. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org.

Give new landscaping plants plenty of room to grow and thrive. Photo: Water Authority

Give New Landscape Plants Space To Grow

When choosing plants for new sustainable landscapes, it’s important to account for the height and the width of each plant species when it matures. This allows you to properly space plants in the landscape without having them feel crowded.  

Proper plant placement, taking into account the mature plant’s size, also should limit the need for future pruning, and reduce the amount of maintenance required in the long run. 

Natural plant shapes and sizes maximize habitat value, but wildfire prevention requires regular pruning and removal of dead plant materials.  

The spacing chart below helps to judge how many plants are needed per square foot, based on the mature size of the plants.  

Space plants on your landscaping plan at their full mature size, not the size when you first plant them. Graphic: Water Authority

Space plants on your landscaping plan at their full mature size, not the size when you first plant them. Graphic: Water Authority

Scale your plants at maturity 

On your landscaping plan, use circles to note the size of every plant at maturity using a scale in which one inch equals four feet. Use colored pencils to note different water needs of the plants selected. It will make it easier to group plants into their proper irrigation zones (hydrozones).

Wide canopy trees that grow to 20 or 30 feet in diameter will significantly change the landscaping over time. Consider whether a tree will cover a large section of landscaping with shade that is currently getting full sun. If plants that thrive in full sun are eventually covered in shade, the landscaping may need to be revised in the future.  

Small but mighty 

Select the smallest, healthiest plants possible, especially when choosing native plants. Once they are planted in properly prepared soil and watered wisely, small plants establish themselves more vigorously than plants raised in larger containers. Do not plant more than the space allows when the plants mature. 

Root depth matters 

Take note of the root depth of plants when they are placed into the landscaping. Note root depths on your landscape plan. Trees will be irrigated less frequently, but for a longer period of time. Groundcovers with shallower roots require more frequent, shorter periods of irrigation. Keep these types of plants in separate hydrozones 

 

This article was inspired by the 71-page Sustainable Landscapes Program guidebook available at SustainableLandscapesSD.org. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org.    

 

 

  

Your plant choices should be governed by the individual hydrozones in your landscaping. Photo: Kelly M. Grow/ California Department of Water Resources

Playing by the Hydrozone Landscaping Rules

Hydrozones are the different areas of your landscape with different irrigation needs. These needs can vary greatly in a single yard. By managing your water distribution to meet the needs of each hydrozone, you can minimize water waste and promote healthy plants.

For example, plants with similar growing requirements including water needs should be planned and planted together so water can be applied as efficiently as possible through rainwater catchment, supplemented by irrigation. 

The amount of sunlight and shade, temperature differences, soil conditions, slopes, and plant root depth should be considered, along with plant water needs, to create hydrozones. Even when the soil is the same, a full sun area is one hydrozone, full shade areas are another, and mixed exposure areas create yet a third zone.  

Within your irrigation system, each individual irrigation valve should water a separate hydrozone populated by plants with similar water needs, living conditions, and root depths. Plants with high water needs such as vegetables or lawns must be on their own hydrozone. Sprinklers or emitters on this zone shouldn’t water anything else, including hardscape areas such as sidewalks.  

Don’t overdo it with irrigation 

 Each hydrozone should have sprinklers or emitters generating the same amount of water, and they should be spaced out so that every plant in the zone gets the same amount of water. If the spray of two sprinklers overlap, plants receiving water from both will receive much more water than they need. In cases like this, sprinklers should be turned away from each other, or placed farther apart. Professional landscapers call this “matched precipitation.”   

This article was inspired by the 71-page Sustainable Landscapes Program guidebook available at SustainableLandscapesSD.org. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org.