If heat was an Olympic sport, we'd be winning gold medals. So... are you surviving? Are your plants? We are experiencing another tough summer due to the excessive heat and the lack of monsoon activity.

Heat stress is apparent on many plants. Ash, elm, and ficus trees are showing leaf scorch and leaf drop. Even cacti and succulents are showing bleaching and sun burning. Proper watering is key and certainly can help.

Here's what was reported by the Phoenix National Weather Service: "July 2024 finished not only as the 2nd warmest July on record, but also the 2nd warmest month on record. It is only the 2nd time in Phoenix's climate history that a month has had an average temperature of 100+, 2nd only to July 2023." This chart tells the story:

Phoenix, AZ Hottest July's on Record

Year        Average Temperature

2023               102.7°F

2024               101.1°F

2020                 98.9°F

2009                 98.3°F

There have been 39 days, so far, over 110°F. But what is toughest on plants are the high overnight temps. The extended heat overnight disrupts the plant's metabolism, reducing the amount of time for photosynthesis, possibly depleting food reserves. Yep, we have a record for overnight temps, too. We have had 25 days, so far, of overnight temperatures of 90°F or greater (surpassing last year's record of 19).

Remember that plants are unable to pick up their roots and move under the shade of a tree or to head up north for the summer. They have other strategies to tough out the heat like dropping leaves or shedding branches until conditions improve. And, sometimes they just run out of energy (food reserves as mentioned above) and/or succumb to disease organisms that may cause them to quickly die. Find our recommendations below for landscape care during extreme heat!

Unfortunately, an excessive heat warning is in effect for the next three days with predictions up to 115°F. And the 10-day doesn't show much chance for rain right now. Do I have any good news? Well, mosquitos don't like excessive heat either. 

Recommendations below are for plants that are established in the landscape (in the ground about two years).

--> Note, the frequencies below have been modified from our normal recommendations due to our record high temperatures.

• Place organic mulch around the base of your plants over plant roots. It will help retain moisture and keep soil temperatures cooler. Be sure to keep it a few inches away from the trunk or stem.
• Water deeply each time you water. Even grass can go 3 days between watering during the hottest days.
• The only plants that need water daily are annuals, vegetables, potted plants, or newly planted plants. Don't water desert trees and shrubs daily as this can cause roots to rot.
• Use light shade covers (about 30% shade) to protect plants from the intense sun until temperatures cool. 
• Mist leaves or surrounding areas with water during the hotttest part of the day. As it evaporates, it cools the surface and surrounding air. It can also benefit birds and other wildlife.

Photo: An agave at Desert Botanical Garden with shade cloth to protect from sun burning.

Our Water – Use It Wisely blog will provide you with some interesting insight as to how our native plants survive and tolerate our harsh weather conditions. Learn about the remarkable adaptations to the challenges of the desert climate. Read the blog.

Photo: Creosote Bush, one of out toughest desert plants.

Aug. 24. SRP Offers Free Shade Trees when you attend an online Shade Tree Planting workshop. Why? To help reduce your cooling costs, improve air quality, and cool our communities (note heat records mentioned above)! Since summer isn't the best time to plant, there will be a tree pick-up event planned for fall. For SRP electric customers only.

Sept. 21. Mesa Electric customers can attend a workshop and pick up their tree the following week. Learn more and register.

If you plant a tree, record your tree to get it onto our planting map at our Trees Are Cool page.

Photo: Desert Willow