desert-landscape

“How much water do my plants need?”

I am often asked this question by desert dwellers and my answer is always, “That depends.”

desert-landscape

There are several variables that determine how much water plants need, along with the frequency of watering.

Variables include:

  • Type of soil (clay, sand, combination)
  • What kind of plant (native plants, higher water use flowering shrubs and ground covers, succulents, etc.)
  • Recommended depth of water
  • Desert region (low-desert, mid-altitude, high desert)
  • Efficiency of irrigation system
  • Water pressure (can vary between neighborhoods)
As you can see, there is no universal watering guideline in regards to how long to water or how often.

Let’s look into the variables a little more closely to help you determine what yours are:

 

SoilClay soils hold onto water longer than sandy soil. They take longer for water to permeate to the recommended depth. The result? Clay soils need irrigation less often than sandy ones but need to be watered for a longer length of time. Phoenix area soil tends to have more clay in them while those in the Palm Springs area are sandy.

Plants – Native or desert-adapted plants need less frequent irrigation versus those that come from tropical climates. Cacti and other succulents do well with infrequent irrigation.

Water Depth – Trees need to be watered deeply while ground covers and succulents do fine at a more shallow depth – shrubs fall in between the two.

Desert Region – Where you live in the desert matters when it comes to water and your plants. The differences include rainfall amounts, when the rain falls, high and low temps, and more. Residents of low-desert cities like Palm Springs and Phoenix need to add water to their plants more often than those who live in higher elevation regions such as Tucson.

Irrigation System – The older your irrigation system, the less efficient it is. This is due to mineral build-up within the system, which affects the amount of water that comes out. Also, old drip irrigation systems tend to accumulate leaks. The average lifespan for a drip irrigation system is 10-15 years. 

Despite these differences, what is a shared characteristic is that the vast majority of desert residents water too often and not deeply enough. This is usually due to lack of knowledge and thinking the ‘more is better,’ especially in the desert.
Landscapers are generally not a reliable source when it comes to scheduling irrigation – most recommend irrigating far too often.
 
So what is a desert dweller to do?
Thankfully, there is very useful information available for homeowners to help them figure out when and how much water their landscape needs.
 
Major metropolitan areas throughout the Southwest have excellent watering guidelines available for residents. The guidelines include the regional variables we have discussed so far.
Here are helpful links based on major desert cities (click the link for the city closest to you):
Watering guidelines are just that – guidelines. Circumstances may mean that you need to water more or less often, but these guides are a useful baseline to work from.
*One final note – before you implement a new irrigation schedule, it’s important to gradually wean your plants to the new one over several weeks. The reason for this is that it allows plants to become accustomed to the new schedule.

Yes, it does take a little work to figure out how much and often to water your plants, but these guides are incredibly helpful and will guide you along the way.

This week, I had the honor of interviewing Joe Lamp’l, host of the PBS series, ‘Growing a Greener World.’ Joe is a well-known figure in the gardening world and is frequently on NBC’s TODAY Show, ABC’s Good Morning America, The Weather Channel, etc. He has several popular books, podcast series, nationally syndicated newspaper column, and has recently launched the website, Joe Gardener where he shares his knowledge for both beginner and experienced gardeners alike.

Joe travels the country touring gardens for his show, and I always come away learning something new from each episode. Last year, he made several visits to the greater Phoenix area, and I asked him what surprised him the most about the Southwest? “I was surprised by the lushness of the landscape,” Joe says. “It caused a mind shift with its incredible diversity and lushness, which catches you off guard along with the unbelievable options and how beautiful it can be.”

His passion for gardening manifests itself through many mediums, and Joe is a passionate proponent of gardening naturally. “Feed the soil (with organic matter), and it will feed the plants,” he states. “Common mistakes that homeowners make is not mulching enough and reaching too quickly for chemical solutions to plant problems.” Through his podcasts, website, and show, Joe talks about natural solutions to common problems along with helpful tips toward a more sustainable garden.

When asked for advice for people new to gardening, Joe says, “New gardeners can sometimes be overzealous; planting too much, and water and fertilize their new plants too much, and as a result, become overwhelmed at the maintenance required. Instead, start out slowly and grow into it naturally. Get out and enjoy your garden regularly and keep an eye out for potential problems by being ahead of it.”

**For those of you who live in the greater Phoenix area, Joe Lamp’l will be giving a Water Conservation and Drip Irrigation Workshop at The Home Depot at 1545 S. Crismon Rd, Mesa, AZ 85209 on Saturday, June 24th. It begins at 10:00 and runs until 1:00. I highly encourage you to go and learn about ways to conserve water in your landscape and the latest developments in drip irrigation, including wifi-enabled controllers.**

I invite you to take some time to get to know Joe better through his show, podcasts, and website – you will learn and be inspired!

Living in the desert southwest, I am blessed to be able to grow a variety of citrus trees in my garden and they do very well under most circumstances.

However, when temperatures outside of the average highs and lows occur, steps need to be taken to protect them. With this week’s record-breaking highs, my orange tree has been suffering as is evident from its sunburned leaves. So I thought, this is a great opportunity to talk about how to protect citrus trees from a heatwave.

 

1. Provide temporary shade 

The west and south-facing sides of citrus trees are susceptible to sunburn during a heatwave. This shows up as yellowing or browning on the leaves on those sides of the tree. Sunburn can also occur on immature citrus fruit, so it’s important to protect them.

While spraying citrus trees with sunscreen isn’t an option, adding temporary shade is. Put a large piece of burlap over the tree, focusing on those south and west-facing exposures. Burlap is inexpensive and does allow some sun to penetrate, which is important. You can purchase burlap at your big box store, nursery, or Amazon (affiliate link below).

Burlapper Burlap Garden Fabric (40″ x 15′, Natural)

You can use a bed sheet in place of burlap for temporary shade. Another option would be to place a shade tent/canopy to help block the sun’s westerly rays.

Shade cloth is very useful as a sun shield when placed on a scaffold or other support – it’s important not to rest it directly on the tree as it gets hot and can burn the leaves.

 

2. Increase irrigation and water early in the morning

When temperatures soar above normal, citrus trees, like most plants, lose more water through their leaves. As a result, their regular watering schedule isn’t enough to meet their needs, so increase the frequency of watering as long as the heat wave lasts. 

When you water is vital as it is difficult for plants to uptake water in the middle of the day. This is because all of their resources are dedicated to enduring the stresses of the heat and it’s hard for them to divert those to uptake water. Water in the early morning, which will allow them to build up a water reserve that will help them through the day.

online-class-desert-gardening-101

Tired of struggling in the desert garden? Sign up for my online course, DESERT GARDENING 101.

Once the heat wave is over, remove the temporary shade and resume regular watering. By implementing these two methods, you’ll enable your citrus trees to weather brutal summer temperatures and minimize any negative effects.

*Sun protection for the trunk and bark of citrus trees is essential throughout the entire year. Here is a past blog post showing you how to shield these parts of your tree and why it is so important. 

 

As most would expect, water is considered a precious resource in the desert. But, did you know that there are more plant problems caused due to over-watering then under-watering?  
 
Believe it or not, it is true. Most people are surprised to hear that up to 70% of residential water usage goes to watering trees and plants in your landscape. This high percentage is because many homeowners over-water their trees and plants.
 
Beavertail Prickly Pear (Opuntia basilaris) and Globe Mallow (Sphaeralcea ambigua)
 
During college, I was fortunate to intern at the City of Mesa Water Conservation Office. The lessons that I learned there would last a lifetime. Nowadays, when I visit clients to help them with their landscapes, over 90% of the time I find that their irrigation schedule is incorrect – they water too lightly and too often.  
 
This results in shallow roots and salt build-up in and around the root zone. (If you have seen a white substance around your plants, there is a good chance that it is the salts from the soil. And just an FYI – just like high amounts of salt are not good for us; they are not good for plants either).
 
Overwatering will weaken your plants, especially during the summer since their roots are close to the surface where they become hot and dry out much more quickly.
 
Trailing Yellow Dot (Wedelia trilobata), Rain Lily (Zephyranthes candida), Desert Spoon (Dasylirion wheeleri)
 
It’s important to note that plants need to be watered deeply, which does two things. First, it causes the roots to grow deeper into the soil, where it is cooler and stays moister longer. Secondly, it helps to reduce the salts in the soil and keeps them away from the root zone.
 
Your plants do not need the same amount of irrigation all year. Plants follow the weather- the hotter it is, the more water they need and when temperatures dip, the less that they need.  For example, I water my garden once every 20 days in the winter, (excluding grass and annuals), and it is healthy and looks great.  If you only take one thing from this article, then please let it be this; CHANGE THE WATERING SCHEDULE ON YOUR IRRIGATION CONTROLLER SEASONALLY. 
 
 
Now, you are probably asking “How do I know what schedule my plants and lawn should be on?”  Well, the folks at Water Use It Wisely is coming to your rescue. They have excellent information for the homeowner on the proper irrigation schedule for your plants. You can view it here:  Landscape Watering Guide  
 
This guide was made for people who reside in the Phoenix metropolitan area. However, people who live in dry climates everywhere will find useful information regarding irrigation, and you can also contact your local extension office for locally published materials. **Most cities have information for their residents regarding watering schedules for their local climate. You can also contact your local cooperative extension office who often have this information as well. 
 
If you find that you have been over-watering your plants, make sure that when you switch to the correct irrigation schedule, that you gradually change the schedule so that your plants have a chance to adjust
 
 
Make sure you have the correct irrigation schedule which lets you have healthier plants, a lower water bill, and helps conserve water.
 
**For those of you not familiar with drip irrigation. The primary way the southwest waters their plants. Water is brought to the plant by a series of plastic pipes, tubing & emitters. The emitters drip water slowly to the root zone of the plant, reducing runoff and allowing the water to permeate deeply into the soil, which saves water.

Baja fairy duster (Calliandra californica) is a must-have for the desert garden.  There is so much to love about this shrub.  

 
My favorite attribute is that it flowers off and on all year.  Its red flowers are shaped like miniature feather dusters.  Also, this plant attracts hummingbirds, is low-maintenance, drought tolerant and great by swimming pools because of its low litter.
 
Baja fairy duster has a vibrant red flower, which is often a color missing in the desert plant palette.  The majority of flowering occurs spring through fall, but some flowering can occur in areas that experience mild winters.  
 
It is native to Baja California, Mexico and is also called red fairy duster by some.  It is evergreen to 20 degrees F.  During some unusually cold winters when temperatures dropped into the high teens, I have had some killed to the ground, but they quickly grew back from their roots. 
 

USES: This shrub grows to approximately 4 – 5 ft. High and wide, depending on how much you prune it, so allow plenty of room for it to develop.  

 
It makes a lovely screening shrub, either in front of a wall or blocking pool equipment, etc.  It also serves as a colorful background shrub for smaller perennials such as damianita, blackfoot daisy, Parry’s penstemon, gold or purple lantana and desert marigold.  
 
Baja fairy duster can take full sun and reflected heat but can also grow in light shade.  It is not particular about soil as long as it is well-drained.
  
 Baja fairy duster in the middle of a desert landscape, flanked by desert spoon to the left and ‘Torch Glow’ bougainvillea to the right.  Red yucca is in the foreground.
 
MAINTENANCE:  As I mentioned before, this is a very low-maintenance shrub.  Some people shear this shrub, which I DO NOT recommend.  This removes most of the flowers and takes away from the natural shape of this shrub.  However, it’s size can be controlled with proper pruning.  Pruning should be done in late spring and should be performed with hand-pruners, NOT hedge clippers.
 
Baja fairy duster does require regular irrigation until established but then is relatively drought-tolerant.  However, proper watering is needed for it to look its best and flower regularly, which is what I do.  


Other than adding compost to the planting hole, no other amendments or fertilizer is needed.  Most native desert plants have been adapted to growing in our nutrient deficient soils and do best when left alone in terms of fertilizing.  I tell my clients to fertilize only if the plant shows symptoms of a nutrient deficiency.
 
So, go to your local plant nursery and get some of these beautiful shrubs for your garden.  Then, while you sit and enjoy its beauty, you can debate what you love most about it….the beautiful year-round flowers, the hummingbirds it attracts, it’s low-maintenance, or come up with your reasons.
 

In the past, people have asked me how long does a saguaro cactus arm take to grow back. The commonly held belief is that it takes 100 years before they will develop an arm.

However, as with much plant information, this answer is not always correct, it actually takes less time for a saguaro cactus to grow its arm back in a landscape setting than it’s native habitat.  

The most critical factor in determining the timing of when a saguaro will start to grow an arm is the availability of water. Put simply, the more water a saguaro receives, the more quickly it grows. In a landscape setting where irrigation is present, a saguaro will grow much more rapidly then they do in their natural desert habitat. Saguaro cacti that grow in southern Arizona (near Tucson) grow more quickly than those in the western areas of the Sonoran desert because there is more rainfall in southern Arizona. 

A saguaro growing in its native habitat can take 50 – 100 years to grow arms. In a landscape setting, arms often appear much earlier.