Redoing Landscapes with "Water Smart" Plants

Q. I am in the process of redoing my front yard to “water smart” landscaping.  We had to pull out an olive tree because olives and rock do not mix, and we cannot seem to control the growth of the olives even when spraying twice a year. I saw an article in the paper where the water company wants us to plant “water smart” trees. However, it does not tell me which trees are “water smart”.  Can you please give me some suggestions?  I have a corner house so it will be in the front yard, full sun.

Texas rangers, aka barometer plant, is native to the Chihuahuan desert of west Texas, New Mexico and the state of Chihuahua in Mexico. It produces flowers on new growth. In the desert of Chihuahua it flowers after new growth from rain, hence aka the barometer plant.

Where to Look for Plants

A. Water smart trees are supposed to use less water than other types. But of course, if you give it more, it will use it. Instead of using 4 to 5 feet of water under their canopies, “water smart” trees can survive with about 2 feet of water applied under their canopy. There is a list created by the Las Vegas water company that you can use. Try searching online for “southern Nevada water authority” and “water smart plants”. You will see two lists: one you can print and one you can search.

Water Smart pdf list

Las Vegas landscape plant searchable database

 Simply substituting lower water use trees and shrubs will not change their need for water. Plant irrigation must be managed.

Most cacti can be planted in full sun.

This mountainous cactus is native to the higher elevations of the Argentinian desert called Monte. It does not have as much intense sunlight as the Mojave Desert. This cactus will survive full sun but is best grown with afternoon shade. It can handle cold (to about 20F) but not the intense sunlight of the Mojave Desert all day long. Different types of cacti have different requirements and landscape exposures.

            Still water deep and not very often. I was at a landscape where it was watered with small amounts of water every day except Sunday. All the plants used could have deep roots if they were watered differently. 

            Other places to look include “AMWUA”. This stands for Arizona Municipal Water Users Association which is the list for Arizona users.

AMWUA plant list

            I believe the water companies want you to use a website that focuses on low water use plants appropriate for this area. Use plants from the US deserts as much as possible. 

             Remember, it is the landscape plant size and total number of plants in your landscape that determines total landscape water use. The roots of plants don't care about "shared" water. They just want enough and applied at the right time. Not little sips of water daily.

Roots Need Air

Instead of watering daily, water with more minutes (deeper) and give the plants a “rest” without water.  Increase the minutes (or the emitter size) they are watered to compensate for “rest” days without water. Do this during the heat. Make sure the plants have at least two inches of mulch on the surface of the soil. surface mulch reduces soil water lost to evaporation. This mulch will give the plants one day of “rest” (without water) between irrigations.

Peruvian apple cactus. Guess where it's from? Tropical parts of Peru, Brazil, Venezuela, and Colombia. This cactus prefers the higher humidity of the tropics but not the intense sunlight of the Mojave Desert.

How to Begin

            Firstly, reduce the total number of plants in your landscape. Eliminate plants that are not necessary. This means some will have to be pulled out. Water delivered to them is shut off or diverted to important and necessary plants. It is easier to reduce the number of minutes delivering water than add more emitters later. Space emitters about 18 inches apart.

            Next, either reduce the height of tall plants by pruning in the late fall or winter or use smaller plants. The plants should grow to a mature height similar to your home. Use these plants to provide shade on the south and west sides where possible.

Accentuate Places That Don't Need Water

            Be creative and leave open spaces in the landscape. If they must be filled, use additions that don’t use water (textural changes using different sizes of rock, wall art, landscape lighting). 

Use different sized rock in the landscape. Different sized rock doesn't use any water.

Wall art doesn't use any water.

            As far as olive trees go, I agree the fruiting is difficult to control but the tree itself will take a lot of abuse including rock!