Landscaping Tips - Caring for Plants as the Temperatures Cool Down

LANDSCAPING TIPS brought to you by the Arizona Landscape Contractors’ Association, the Sustainable Landscape Management (SLM) and the Arizona Certified Landscape Professional (ACLP) programs.



In the 62 days of July and August of 2020, there were 35 days in which the day temperature was greater than 110°F.  There were 27 nights in which the “low” temperature was over 90°F with an additional 14 nights that the low was either 88°F or 89°F.  These temperatures were brutal on our plants; plants that are adapted to annual averages for these two months of 105.5°F days and 83.5°F nights.  This summer of 2021, there were 12 days with temperatures greater than 110°F, seven nights with the “low” temperature over 90°F and 13 nights that the low was either 88°F or 89°F.  What a difference a year makes!


Once the temperatures begin to drop to more manageable levels in the fall, the challenge is how to return to normal maintenance practices in the best interest of the plants.


  • Gradually return to the established fall watering schedule over several weeks, not several days.
  • Mulch surfaces that have not been mulched; a practice that may prove to be a permanent strategy.
  • Remove dead, diseased or dying plant parts injured by the heat.
  • Check for insect or disease problems and act accordingly.
  • Some plants may benefit from a light fall application of fertilizer but not so much as to stimulate a lot of new growth that could be damaged by colder temperatures later in the fall.
  • Evaluate marginal plants and replace with more suitable plants that may better withstand extremes in temperature or higher average temperatures.
  • Fall is a great time for planting landscape ornamentals, annuals and perennials. The mild temperatures provide for better establishment and growth of new plantings.


Although the summer of 2021 has not been as hot as the summer of 2020, and the monsoon season provided much needed rain, there are concerns of increases in temperatures in the future and the impact those higher temperatures may have on existing plants and those plants recommended for future landscapes.  Water availability may also be a concern.  Sustainable landscape practices should always be the driving force behind the best decisions for the future of our landscapes.