Pima County Monthly Garden Reminders for July

Guide
Authors
Paul Larson
Laurie Vance
Deborah North
Publication Date: January 2025 | View PDF

The beauty of the desert shines this month with temperatures more than 100°F, our monsoon moisture begins, and if we’re lucky, rain and cooler evenings bring welcome relief. Continue to focus on early morning or late evening gardening to avoid the peak heat. The arrival of monsoon rain provides an excellent opportunity to plant heat-tolerant and monsoon-adapted plants and flowers. Although your garden will greatly benefit from the additional humidity, proper mulching and watering techniques are crucial to ensure plants thrive in these extreme conditions.

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Maintenance

  • You can prune Mesquite, Eucalyptus, and Palo Verde trees this month; they heal quickly during the hot weather.  Some sap loss from pruning may occur, but it will not harm the tree.  Do not put any sealers on the pruning cuts, and never remove more than one quarter of the tree canopy at one time since the remaining leaves provide the photosynthesis necessary for health.
  • Monsoon season brings intense storms with strong, damaging winds.  Trees with very heavy leaf canopies are more likely to be injured by strong winds.  Some thinning of internal branches may be necessary to prevent storm injury from the sail-effect of these canopies.  If required, remove storm-damaged limbs by pruning back to a side branch or the main trunk.
  • Remove faded blossoms on flowering plants to direct the plant’s energy to forming buds, not seeds.
  • Pick melons when they ripen.  Watermelons that are ripe will have a patch of yellow on the underside of the fruit. If the patch is still white, it is not ready.  Tendrils on the vine just above a ripe melon should be brown and shriveled.  Green tendrils mean the watermelon is not ready.  Checking for cantaloupe ripeness on the vine is done by pressing lightly on the blossom end.  If it gives slightly, it’s probably ripe.  Melons ready to pick often have a sweet fragrance.
  • Check your tomato plants for hornworms.  Hornworms will metamorphize into beneficial pollinators, but if you do not want to sacrifice your tomato plants, you can move them to another nightshade plant, or remove them by hand and discard them away from the plants.  Birds will eat them.
  • Established warm-season herbs in containers such as lemon verbena, basil, and lemon grass will benefit from some late-afternoon shade this month.
  • Spread 3 inches of mulch under plants if not done so in prior months; keep the mulch a few inches from the main stem or trunk.
  • Continue using 30%-40% shade cloth to protect vulnerable plants during extreme heat. Clip cloth to poles to hold it a few feet above plants.
  • Monitor prickly pear for cochineal scale.  It appears as a fluffy white tuft at the spines.  To remove it, use a firm jet of water to spray the “fluff” and red-colored insects off the plant.

Planting

  • Plant pumpkins from seed to harvest for Halloween.  Most varieties mature in 100-120 days.
  • Continue planting seeds of beans, corn, melons, and squash.
  • Flowers such as zinnias, Arizona poppies, sunflowers, and “monsoon wildflower seed mixes” can be planted now from seed.
  • Cacti and agave can continue to be planted or transplanted this month.
  • Palms can also be planted now since the soil temperatures are high enough.
  • Avoid planting cool-season vegetables such as cilantro and parsley now, as the heat will cause them to bolt and flower.

Fertilizing

  • Fertilize palms with fertilizer designed specifically for these plants; follow the directions on the package carefully.  Immediately water it in well.
  • For those with roses, you have two choices:
    • Give your roses a break during July and August with no fertilizer applications. Start back with full-strength slow-release fertilizer in September.
    • Continue using slow-release fertilizer at half-strength throughout the summer, then change back to full-strength applications as above.

Watering

  • In recent years, monsoon rains have started in early July; adjust your watering frequency as appropriate since monsoon supplements or replaces some of your planned onsite watering.
  • We urge you to consider rainwater harvesting.   Even if you do not have a current system, monitor water flows in your yard as the monsoon comes.  Take notes or record video so you can make changes to passive rainwater harvesting patterns once monsoon ends.  Active rainwater harvesting can be started on a small-scale during monsoon from your patio or roof into wooden barrels or plastic trashcans.  Keep the containers covered or use fine screens to prevent mosquito breeding.  Attach a hose bib near the bottom to distribute the rainwater to your garden.
  • Avoid use of “container saucers” under plants and monitor your yard for other areas of standing water. Standing water in saucers or anywhere else in your yard can quickly promote mosquito breeding.  If you must use saucers due to staining of patios, empty them frequently or consider using mosquito dunks or Bacillus thuringiensis israelensis (Bti).
  • Water roses as usual no matter which fertilization option you picked above.
  • Newly planted palms need more water than established ones, so if your local monsoon is inadequate, supplement.
  • Water lawns in the early morning (best from 4-8 AM).  High summer humidity coupled with nighttime or evening watering can encourage fungal diseases.
     

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