Too Much Water Equals More Pruning, a Backache and More $ Spent in the Garden

irrigation schedule

Did you know that just by making one change in your garden that you will benefit not only the earth, but also your plants, your back and your pocketbook?  The one change I am talking about is making sure that you are watering your plants at the recommended rate for your area. 

Okay, first the benefits to the earth.  The first one is fairly obvious….by watering at the proper rate and frequency, we are conserving water – a precious resource.

irrigation schedule

Now the first benefit is fairly obvious, but here is another one….did you know that when plants are watered correctly, that they produce less excess growth and grow at a healthier rate?  Many of us do not take that into consideration or even think of it. 

Each time I consult with a homeowner, I often go over what their current irrigation schedule is.  Believe it or not, over 90% of the time, I find that their trees and plans are being over-watered.  In fact, one of my horticulture professors did a study and found the same statistics.  Naturally, that is understandable; we live in a desert, so logically we think that more water will help our plants.  

But, the truth is, is that the majority of plant problems we see related to irrigation is due to over-watering NOT under-watering.  

irrigation schedule

Mature shrubs and trees need less water then you may think – especially if you are growing plants that are adapted to our arid-climate.  In response to over-watering, the extra growth that is produced has another interesting effect….it causes the plant to use more water in order to maintain the excess growth then the same type of plant being watered at the proper rate.

Irrigating (watering) correctly not only causes your plants to grow at a healthy rate, but also encourages roots to grow deeper where the soil is cooler and moister and helps to flush out salts in our soils that can build-up around the roots of your plants.  As a result, your plants will be better able to withstand the stress of summer.

irrigation schedule

Here is an example for our area (around Phoenix): Did you know that your mature citrus trees only need to be watered every 21 – 30 days in the winter and every 7 – 10 days in the summer?  The past three clients I consulted with, who had citrus trees, were watering them 3 times a week in the middle of winter.  They were not watering them long enough and not deeply enough.  Many of their trees were suffering multiple problems related incorrect irrigation, which were easily corrected by changing their watering schedule.

Okay, you may be saying, I don’t have any citrus, so how does this apply to me?  Well then, here is another example; desert-adapted shrubs need water every 7 – 10 days in the summer.   Even mature shrubs that are high-water use only need water every 5 – 7 days in the summer.   Most people are watering their shrubs every 2 – 3 days in the summer.  *I water my own shrubs every 7 – 10 days throughout the summer and once every month in the winter and my garden is thriving.

irrigation schedule

Now, for the savings….you do the math – with less growth, there is less pruning required and therefore less maintenance.    So, we are not only conserving water and saving $ off of our water bill, but also using up less space in the landfill and also saving you money (if you use a landscape company to prune your trees and shrubs).   Or at the very least, saving you a backache from all of that extra pruning you are saved from doing ;^)

All right, you are saying, that sounds great….save the earth, healthy plants, less pruning and saving money – all good things –  I’m on board, but what do I need to do to get started?  

irrigation schedule

Okay, here are the keys to watering your plants the right way – it all has to do with how deeply your plants are watered and the frequency.  Trees should be watered to a depth of 3 ft. and shrubs to a depth of 18 – 24 inches.  The trick is, figuring out how long you need to water each time to reach the recommended depth.

The length of time for each irrigation cycle can vary depending on your individual system.  So, to do this, all you need is a 3 ft. piece of rebar, (seriously, that is it).  Once you have irrigated (watered) your plants, gently push the rebar down to see how far the water has penetrated.   It will slide easily down through the moist soil.  When it stops, measure the distance on the rebar to see how far it penetrated and you can see how much longer or shorter a time you will still need to water.

*The average time the water should be turned on for shrubs is approximately 2 hours at a time, but this can vary depending on your irrigation system and soils.

irrigation schedule

Adjust how often your water (the frequency), seasonally.  Plants do not require the same amounts of water in winter then the rest of the seasons.  However, the length of time you turn on the water does not change.  

Even though the specific recommendations of this post are geared for the desert gardener in Arizona, the broader principles can apply to us all.  For those of you who do need to provide supplemental water to your plants, take the time to make sure that you are watering them correctly. 

I would like to offer one word of caution, when changing your current irrigation schedule, gradually wean your plants from the excess water they have been receiving – you don’t want to shock your plants and it will take them some time to adjust to the longer length of time between each watering cycle.  

I am joining with Jan from Thanks For Today and other fellow garden bloggers in sharing ways to garden sustainably in honor of Earth Day and this is my submission :^)  Please visit her blog to see links to other posts honoring Earth Day.

Garden Bloggers Sustainable Living

Garden Bloggers Sustainable Living

*For landscape watering guidelines in greater Phoenix area, please visit AMWUA which is an excellent resource on irrigation which has more specific information on how often to water seasonally.

*For guidelines for watering citrus, please check out the following link.

“The Joy of Composting”

Noelle Johnson, aka, 'AZ Plant Lady' is a author, horticulturist, and landscape consultant who helps people learn how to create, grow, and maintain beautiful desert gardens that thrive in a hot, dry climate. She does this through her consulting services, her online class Desert Gardening 101, and her monthly membership club, Through the Garden Gate. As she likes to tell desert-dwellers, "Gardening in the desert isn't hard, but it is different."
31 replies
  1. Liza
    Liza says:

    Noelle, this is wonderful information. I really appreciate you sharing. Watering less frequently makes so much sense, especially in our desert regions.

    I also meant to tell you that I really enjoyed your post on plants planted in the wrong places. It changed how I view landscaping as I drive around Albuquerque – now I'm on the lookout for examples of incorrectly planted trees! It makes my days a lot more interesting, so thank you!

  2. jodi (bloomingwriter)
    jodi (bloomingwriter) says:

    Excellent post, Noelle! I like that you point out the perils and wastage involved in overwatering plants, especially in a climate such as yours. Here in my garden, I water the containers of annuals, and newly planted perennials and shrubs. That's it. Things are mulched, we have fog and often soggy weeks in the summer, and clay soil. When I talk to other gardeners or write articles, I always recommend they use drip or trickle hoses rather than sprinklers that fling water everywhere and basically waste hugely. Water's a resource we don't want to waste, but many don't get that yet.

  3. Jan (Thanks For Today)
    Jan (Thanks For Today) says:

    Your post is wonderful, Noelle…such good information you included. I have lived in such a variety of climates, some requiring little to no watering, some requiring more–but it's so important to be 'aware' of how much water our plants actually require. I've been guilty of over-watering at times in the past and I am bound and determined to be more educated and aware of my actions this year. Thanks for your participation;-)

  4. Janet
    Janet says:

    Very informative Noelle. Hard to believe that one can over water plant material in a desert climate. Good information for all of us.

  5. tina
    tina says:

    Such good tips Noelle. I think watering is indeed a hard thing for people-even for me. I have tons of rebar around here so I think I'll try out your tip. Your garden photos are so gorgeous. They all make the desert look wonderful (this from an east coast girl who is used to only forests and really can't imagine deserts being beautiful-but don't hold that against me ok?:)

  6. sweet bay
    sweet bay says:

    In this post I am especially appreciating the sunny pictures of beautiful desert landscaping, it's so cold and muddy here right now.

    The only things I watered last year were the new plantings around the house — watering can get really tiresome for sure, not to mention my guilt about using water and the well pump.

  7. Brad
    Brad says:

    Thank you so much Noelle. When visiting my parents in Phoenix this Christmas I was horrified to find out they have the irrigation on several times a week. I told them to turn it down, but I wasn't sure how much. I'm forwarding this post immediately.

  8. Carol
    Carol says:

    Great post Noelle! It is so true that most water more often than needed and never deep enough. I am intrigued with these gardens! Are these your designs? Your garden? Beautiful gardens and photos! The light, forms, colors and textures are so amazing in some. Gorgeous! Makes me want to move to the desert! Pronto!! ;>)

  9. Carol
    Carol says:

    I should add that it is so important to educate folks about conserving water… especially when living in a desert! But this is a universal problem and your tips are great! Well Done!

  10. Kathleen
    Kathleen says:

    Very informative post as usual Noelle. The landscaping on the properties accompanying your post are beautiful too. I know I don't water properly. I have a sprinkler system so it should be easy to switch when and how long I water but I know I'm horribly uneducated regarding doing so. My promise toward making a smaller carbon footprint will be to look into that this season before it gets turned back on! I wish I lived near you ~ I'd just have you come over and help me!

  11. gippslandgardener
    gippslandgardener says:

    Thanks for such an informative and thought provoking post Noelle! Citrus is one of the few things I water in my garden since the drought and resulting watering restrictions, but I've never been sure how much how often – so this has been a wonderful help!

  12. Rosie
    Rosie says:

    Hi Noelle this is great information even for us UK gardeners. Over here in the summer its lawns that get overwatered. I'm a great believer in letting the roots get down deep so I water now and again but when I do water I give the plants a good soak.

  13. debsgarden
    debsgarden says:

    Is this your home , Noelle? It is gorgeous! All your plantings are beautiful and healthy. We have had weeks of rain here. We sometimes have drought-like conditions in summer or fall, but not this past year. I rarely water except when I first plant something and am helping it to become established. With my large yard it is a huge chore to water plants. I have a few plants that can't take drought; I put them close to the house so I can remember to water them when needed.

  14. James Missier
    James Missier says:

    I find that over-watering kills in equal propotion of under-watering.

    But I wonder whether it applies differently when it comes to a tropical garden where it rains heavily for hours everyday.

  15. azplantlady
    azplantlady says:


    I am so glad that many of you found this post so informative. Sometimes you never know if anyone will even take the time to read what you write, especially when dealing with a specific issue such as this. For those of you who asked if any of the landscape photos are of my home, the answer is no. They are from a community where I do quite a bit of consults and it sits right in the middle of the desert and is so beautiful.

  16. Shady Gardener
    Shady Gardener says:

    Wow! What great information!! I'm going to send your blog address to friends of mine that just moved (permanently) to Mesa. I'm SURE they'd be happy to learn about this subject! 🙂

  17. Muhammad khabbab
    Muhammad khabbab says:

    Very informative. I think people over water more than under water. Water conservation is something gardeners in our area are not aware of. I am sure this article of yours will spread lots of awareness. thanks for sharing

  18. Autumn Belle
    Autumn Belle says:

    Noelle, this is a very informative and interesting post. I tend to over water than under water. After reading your post, I am even more convinced to change my watering habits 😛

  19. Martha Z
    Martha Z says:

    Great post and very helpful. Since I am gone much of the time in summer I am still struggling with the problem of getting the right amount to both shrubs and vegetables on my drip system. It wasn't possible to group like plants as effecently as I would like.

  20. Andrea
    Andrea says:

    VEry informative and interesting post. Proper watering is important for all climes not only for the dessert. For non-horticulturists that will definitely be a big help. But i am a horticulturist too, so i opted to appreciate more the photos and the landscape. May i know the name of that violet bloom?

  21. Christine
    Christine says:

    Great and useful post, Noelle! Another negative aspect of over-watering is that the soil composition can change. I replaced a client's lawn with natives and noticed the the soil under the lawn was the densest clay I've ever worked with. The irrigation system was poorly designed and as a result they watered more to compensate. A reminder to leave this sort of stuff to the professionals!

  22. Barbara
    Barbara says:

    What good and obviously professional advice. Since water conservation is not an issue where I live, I'd never really thought about it. So your points about it not always being good for the plants and not being economical were very interesting. Thanks for an informative post.

  23. Anonymous
    Anonymous says:

    Noelle, great insight into the desert garden. I have a question. We put in a palo verde last year here in San Diego. It was doing fine until the heavy rains this year. Half of the branches have gone brown and it did not bloom. I have trimmed back a couple of branches and they are still green inside. How should I trim it to bring it back? Thanks, Jeff

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