To keep or not to keep? That is the question!

As more and more people convert their yards into a sustainable landscape, some are torn by their love of their favorites – such as hybrid roses – that are not “low” water- use plants. This doesn’t have to be a war of the roses!

The answer is to hydrozone your plants.

Hydrozoning is the practice of grouping plants by their similar water and sun needs.  By grouping plants into zones, it helps in your overall maintenance—watering appropriately, ensuring healthy plants, and allowing you to keep your more “moderate” or “high” water-use plants. By grouping them together, it ensures they get the water they need separate from your other “low” or “very low” water-use plants.

What does this mean for my irrigation system?

Typically, irrigation systems are already designed to water a yard, by breaking it up into zones, such as front yard, back yard, side yard, etc. They are set up to deliver the same amount of water to every plant in that zone. When there are plants with different water needs in the same zone, it is a wasteful use of water and can result in plants being over-watered or under-watered—dying as a result.

What are steps I can take to hydrozone my plants?

Step 1: Know the water needs of your plants

We recommend consulting WUCOLS – The Water Use Classification of Landscape Species. This on-line resource provides guidance related to the irrigation water needs for over 3,500 plants used in California landscapes. Go here to access the site.  Once there:

• Go to the bottom and click on WUCOLS List for All Regions. If you are in the Los Angeles area, you will be looking at either the South Coastal (Sunset Climate Zones 22 – 24) column or the South Inland Valley (Sunset Climate Zones 18 – 21) column depending on where you live. (If you don’t know your climate zone, go here.)
• Follow the column down until you locate your plant by botanical name.
• Take note to see if the plant is listed as a very low, low, moderate/medium, or high water-use.   

Step 2: Group your plants by water and sun need

Different zones might look like this:

• Moderate/medium water-use plants that like more shade
• Low water-use plants that prefer sun
• Very low water-use plants that prefer sun

It may require replacing or relocating some of your plants.

Here’s a simple sample sketch:

Step 3: Place irrigation appropriately

Each zone is irrigated on a separate valve/station, and can be adjusted to deliver the amount of water the plants need without over- or under-watering any of them.

• Trees should have their own zone.

• If you haven’t already, this may be a good time to convert to a drip irrigation system—even more efficiency! If you want to convert to drip from an existing irrigation system, we recommend consulting a professional to ensure the right equipment is used.
• Be sure that water gets to where roots grow.  Don’t place drip irrigation emitters against the base of the plant. Instead, circle around the plant starting 1 foot out from the base, to reach the root system that spreads out from the plant.

Speaking of more efficiency…

Use these resources—there are rebates available to offset the costs!

• Smart Controller: also known as a Weather Based Irrigation Controller (WBIC). It accurately applies water only as needed according to local weather conditions. Go here to learn about rebates.
• Water Calculator: Check out the Metropolitan Water District’s water calculator to help with water schedules. Check it out here.

As Shakespeare wrote, “Why do we make war? Why must some of us dominate and die?” It doesn’t have to be the plants in your garden!

Want to learn more? Join us for a hands-on workshop on pruning and maintaining your sustainable landscape?

Join us on Saturday, March 30 for a 4-hour Sustainable Landscape Maintenance Workshop that will cover soil health, plants and pruning, irrigation and watering considerations, rain barrels and more. Go here to register.  This workshop is sponsored by Los Angeles Department of Water and Power for customers in the LADWP service area.