Garden Calendar for May 2019

Time to get your garden ready for the summer ahead. Most garden tasks this month revolve around making sure the irrigation system is working, and fertilizer to encourage fruit production plus warm-season growers to grow.

Tune Up Your Irrigation System

Irrigation systems require checking and tune-up on a regular basis. Some tasks should be done once per month, some should be done quarterly – as the seasons change.

Tune up irrigation system now with these tasks.

* Clean filter, this may include a soak in white vinegar.
* Flush out debris – to take off all end caps and run the system to flush out any gritty bits generated by time and our naturally calcium-rich water.
* Check timer settings. Change from spring to summer program.
* Walk the lines and check the system for leaks or lost emitters (a monthly chore).



* Fertilize established Bermuda grass lawns with a high nitrogen fertilizer. Wait at least 2 weeks since last application.
* Roses do well with fertilizer every two weeks through the bloom period.
* Fertilize deciduous fruit trees (almond, apple, fig, pomegranate, etc) with a fruiting fertilizer any time during the month. Do NOT use too much since it may cause excessive fruit drop.

* After mid-month, fertilize citrus with a fruiting fertilizer (high in phosphorous). I fertilize on Memorial Day because the next dose is on Labor Day and it’s easier to remember.


* After mid-month, fertilize established palms with a high nitrogen fertilizer. If they are date palms, and you want dates, use a fruiting (high phosphorous) fertilizer instead. I fertilize on these on Memorial Day as well.

Note – No fertilizer for the plants in the Legume or Pea Family.  “Legumes” includes acacia, mesquite, Mexican bird of paradise, Texas ebony, fairy duster, and all the others that make pea-like pods. When in doubt, Wikipedia can help tell you what family a plant is in. Garden nerds like myself are constantly adding horticultural data to the site. Or ask me on my Facebook page, but please post a good picture of both overall plant and leaf close-up.

* Apply soil acidifier to alkaline-induced chlorosis plants.  More on this later.

Moss rose comes with a label that says “full sun” – but they appreciate at least part-day shade in the Southwest.

Tasks for the Month

Anytime during the month:

* Add color with heat tolerant annuals like sunflower, celosia (cock’s comb), gallardia, and moss rose (Portulaca).
* Plant hot season vegetables and herbs, including: amaranth, muskmelon, okra, pepper, squash, tomato, basil, marjoram, oregano, and rosemary.
* Mulch with organic mulches if you haven’t already.

* Plant or transplant cacti and other succulents, such as agaves and hesperaloe.
* Blast spider mites off evergreens with water or spray with insecticidal soap. Repeat as needed at least every other day for 10 days until mite population is knocked back.
* Remove spent flowers (deadhead) to prolong bloom on roses and annuals.  More about deadheading here.

After mid-month:

* Harvest any ready onions, shallots, and garlic.
* Watch for caterpillars and treat with insecticidal soap. Problems are grape-leaf skeletonizers on grapes, skeletonizers on Texas mountain laurel, and orange dogs on citrus.


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2 thoughts on “Garden Calendar for May 2019”

  1. Deadheading refers to removing the spent flower down to the first set of leaves below the flower. All you are removing is the dead head.

    Extensive rejuvination pruning should be done next January when the roses are dormant.

  2. I took several of your classes and now I am living in a retirement area and taking care of the roses that are neglected. . They never get trimmed . Please give some help about how far back to deadhead them.
    Thank you
    Doris Nicholson

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