June/July 2023 Garden Checklist and Solutions
All Elevations
June is usually the hottest and driest month in Arizona. This is stressful on many plants, especially cultivated garden flora. Hopefully, the vegetables you planted in late winter and early spring are growing well thanks to your preparation. If you haven’t already, now is a good time to remember to adjust irrigation for warmer weather. Once the monsoons begin in July, it may be time to scale it back, depending on how much rain your microclimate receives.
Water is critical no matter where you plant. The variable weather we experience throughout our seasons offers some challenges in setting the controls to best suit the wide variety of plant needs. Being able and willing to adjust irrigation as needed helps maintain healthy plants.
Continue to monitor weeds and remain vigilant. Each season brings a new collection of weed species. By the time we are finished with the winter annuals, it’s time to address the summer weeds that come with seasonal rains. Insects do well in warm months, so it is wise to continue to keep an eye out for emerging pest problems. Things to look out for in the garden that may indicate hidden pests include discolored plant parts; chewed or missing leaves; holes in stems and bark; and frass (aka insect excrement). Camouflage is one of the strengths of the insect world. Patience and a hand-held magnifying lens are often required for bug crime-scene investigation. The same goes for disease pathogens. If you are not sure, it is best to consult an expert, such as your local cooperative extension office. Most insects are beneficial, but to avoid ones that damage your plants, it is best to confirm the pest type so you can take appropriate action, not simply spray and pray.
Not a lot of pruning is necessary during the summer months, but for some plants, this is a good time to maintain. Palms, for example, may be trimmed to limit the amount of flower stalks, fronds and kernels they drop on your landscape. This is usually a job for a certified arborist. Climbing trees is dangerous, and most of us lack the proper equipment. When hiring a professional, request the “9:00 to 3:00” trim so they don’t take too much off the top. Pruning isn’t exactly like getting a haircut. While palm parts will grow back, they are also the place where these trees photosynthesize. They need enough green to maintain good health. Deadheading flowering shrubs, pruning out dead branches, or otherwise keeping things to a manageable size is more appropriate for a weekend gardener. You still need good, sharp saws and pruners, but at least you don’t have to leave the ground behind to do it.
Low to Middle Elevations
Due to the omnipresent heat, June is not a great month to plant. Mostly, it is a time to maintain and troubleshoot things already planted. Once the monsoon season begins—usually around the first week of July—there are opportunities to plant again. While temperatures remain hot in July, the additional rainfall and accompanying humidity give plants a greater chance of survival. Plant bush and pole beans, sweet corn, pumpkin and winter squash now. The monsoon season is good for sowing seeds of plants that naturally survive on summer rains, such as poppies, desert senna, primrose and zinnias. There are monsoon seed mixes available at places such as Native Seed/Search (nativeseeds.org) and your local seed library. Nurseries that specialize in native plants may also have these seeds, as well as plant starts that may naturalize to the area they are planted.
There is a tree blooming in a shaded courtyard outside my office, and I’m wondering what it is. It resembles a pear tree and has white/green blossoms with an unpleasant odor. My best guess after an online search is that it may be a Callery pear. Any ideas?
You are correct. The tree in question is a Callery pear (Pyrus calleryana), an ornamental pear tree bred to produce flowers but not edible fruit. They became very popular in the last quarter of the 20th century. The most common variety is ‘Bradford,’ although there are at least two dozen others. As you noticed, the flowers have an unpleasant odor and are best observed at a distance. Another unfortunate feature of Bradford pear trees is their tendency to grow branches from the trunk at sharp angles, predisposing them to break in high winds. One benefit of this tree is its resistance to fireblight, a disease that affects other pear trees. Newer varieties have been bred for better features, but fireblight continues to be a concern.
How can I keep the mice out of my compost?
It is difficult to keep rodents out of anything. You could try snap traps baited with peanut butter outside the base of your compost bin, but a more humane approach is to deter them by using hardware mesh with quarter-inch holes that mice cannot squeeze through. Using a bin with a lid can also help keep the critters out. Make your compost habitat less appealing by turning the contents once per week. Compost material reaches a fairly high temperature in the middle, and no mouse is going to set up housekeeping in that heat.
I occasionally run across dead branches on my mesquite trees. On closer inspection, I noticed a ring around these branches etched into the bark. The foliage in front of this ring is dead, but everything appears to be fine behind it. Should I be concerned, and can I do anything to prevent this?
The ring etched in the bark is the work of the mesquite twig girdler (Oncideres rhodosticta). This member of the Cerambycidae family is commonly referred to as the long-horned beetle due to its lengthy antennae. The female chews a ring in the stem and deposits her eggs further out. The eggs hatch in the stem and the larvae feed on the dying wood caused by the girdle cutting off nutrients to the end of the branch. The larvae will winter in the wood, and adults will emerge in the spring.
The good news is you don’t have to do anything to prevent these beetles from chewing on your trees. Research has shown the damage does not affect the health of mesquite trees and is simply nature’s way of pruning.
High Elevations
People who live above 3,000 feet have many options in June. In addition to the beans already mentioned, consider lima beans, Brussels sprouts, cabbage, broccoli, peas, cantaloupes, carrots, cauliflower, celery, collards and squash. There are also seed mixes for higher elevations that contain plants suited for those areas: poppies, sunflowers, nasturtium and marigolds as well as many more. June is toward the tail end of summer bulb-planting season, so if that is your goal, don’t delay.
Do you have a question about gardening in Arizona? Send your queries to plant and insect specialist Peter L. Warren at plwarren@vt.edu.
