Sheilah Britton, Pinal County Master Gardener
According to the National Weather Service, monsoon season officially begins on June 15, which means we might expect to see rain, flooding, lightning, wind, and dust sometime in the next few months. But, we haven’t really had a monsoon for the past two years, so how do we proactively approach the summer months based on what has happened in our gardens and landscapes in recent years?
It is important to know what we are missing when there is no precipitation during the monsoon. Average rainfall for Tucson is around six inches per summer and slightly more for SaddleBrooke and SaddleBrooke Ranch. That is roughly half of our annual precipitation for an entire year. When you factor in the conditions we have experienced in recent years, we are currently in a prolonged drought, and many plants, including native vegetation, have already been exposed to damage.
“Deeper rooted plants like non-native trees probably already need supplemental watering,” says Michael Crimmins, professor of climate science at the University of Arizona. “The deeper soil moisture accumulates over numerous months and seasons, so drought conditions from last spring/summer are showing up now at deeper depths.”
Check your garden for signs of stress, including leaf drop, dry and wilted leaves, sunscald, and signs of reduced growth in trees and shrubs. It is important to replenish water to trees that have been affected by drought, as weakened trees are more susceptible to insects and disease.
“Trees and shrubs are the backbones of your landscape and should receive prioritization, receiving water that is appropriate for their depth and allowing some drying between irrigation,” says Ursula Schuch, professor of environmental horticulture at the University of Arizona. She also recommends minimal pruning and not fertilizing water-stressed trees.
Most of our landscaping at SaddleBrooke and SaddleBrooke Ranch includes a variety of plants that require different levels of irrigation. Irrigation systems should be designed to deliver water needs to similar zones; low water use plants should be separate from plants that require supplemental water. Cacti, succulents, ornamental grasses, and bedding plants need irrigation specific to their needs. Base your calculations on plants’ root zone and let the soil dry out between irrigations. When in doubt, use a soil probe.
Finally, as our climate continues to change with rising temperatures and less precipitation, it is best to consider what you plant, how that plant will grow, and the water it will need to thrive. “When people are planting new trees, they should understand how much water will be necessary for different species to keep these trees healthy as they grow larger and will require more water,” Dr. Schuch advises.
For more information on this topic, visit Dr. Schuch’s recent publications at https://extension.arizona.edu/pubs/drought-extreme-heat-plant-responses-landscape-maintenance-practices and https://extension.arizona.edu/maintaining-landscapes-during-heat-drought.
SaddleBrooke and SaddleBrooke Ranch Master Gardeners are volunteers trained under the auspices of the University of Arizona Cooperative Extension, Pinal County. We offer educational programs and classes to residents of our communities.
Please visit our new website at extension.arizona.edu/saddlebrooke-master-gardeners.
Need advice or have questions about your own garden? Send an email to [email protected] and include your name, address, phone number, and photos of your issues.