A Queen Creek Nursery’s Free Citrus Class on Nov. 7 Comes Right Before Backyard Trees Face Their Toughest Months

If a lemon or orange tree in your yard put out a surprise round of blossoms this fall, it may be telling you something about its summer. University of Arizona research shows that citrus often blooms about a month after a stretch of drought stress, once the tree recovers. An abnormal bloom in September or October, the university’s Cooperative Extension says, is a good sign the tree went short on water during the hot months.

Questions like that are the point of a free class coming up in Queen Creek. Desert Horizon Nursery, a locally owned nursery and garden center at 19250 S. Ellsworth Road, is holding Citrus Success, a fall citrus care class, on Saturday, Nov. 7, at 10 a.m. The nursery describes it as a chance to “learn the dos and don’ts for caring for your new or established citrus trees,” with an open question-and-answer session with its staff at the end.

For San Tan Valley, Queen Creek and Gilbert gardeners, it is a short drive on a Saturday morning, and it costs nothing.

What the class covers

The nursery’s event listing names seven topics: citrus varieties and their attributes, preparation and planting, proper watering, proper pruning, proper fertilization, disease identification, prevention and treatment, and a question-and-answer session with what the nursery calls its resident experts.

That list follows a citrus tree through most of its life in a desert yard, from choosing which kind to plant to figuring out what is wrong with it years later. The Q&A is likely the most useful part for anyone who already has a tree. Bring a photo of the leaves that worry you, the label from your fertilizer bag, and a rough idea of how often your irrigation runs.

The class is free, but the nursery asks people to RSVP through a short form on its website. The form asks for your name, your email and how many people will attend. There is an optional box to sign up for the nursery’s newsletter, which it describes as a short email most weeks with new arrivals and upcoming class dates. The nursery says it uses the information to plan the event and does not share it.

A second free class on Nov. 14

One week later, on Saturday, Nov. 14, at 10 a.m., Desert Horizon is holding Caring for House Plants. It uses the same format as the citrus class: varieties and their attributes, preparation and planting, watering, pruning, fertilization, disease identification, prevention and treatment, and a closing Q&A. It also asks for an RSVP.

The two classes round out the nursery’s fall lineup. Its first free class of the season, on container gardening, was held Oct. 17, and a Plant Problems and Solutions workshop followed on Oct. 24. The nursery says its classes are hosted by its own nursery professionals, are “always free to attend,” and are meant to give people “practical, trustworthy information you can actually use.”

Desert Horizon says it stocks plants chosen for East Valley yards in Queen Creek, San Tan Valley, Gilbert, Chandler and Mesa, including shade and citrus trees, desert-adapted shrubs, cacti and succulents, houseplants and seasonal color. Its citrus selection includes lemons, limes, oranges and grapefruit suited to the low desert, and the nursery notes that the varieties on hand change through the season. It is open seven days a week, from 7 a.m. to 5 p.m. Monday through Saturday and 9 a.m. to 4 p.m. on Sunday. The phone number is 480-987-3308.

What the research says about watering now

Citrus care in the low desert has been studied for decades, and the University of Arizona Cooperative Extension publishes free guides that make good homework before the class. Its guide to irrigating citrus, written by citrus specialist Glenn C. Wright, starts with the warning signs. The first noticeable sign of water stress, the guide says, is leaves that turn a dull green and curl from the edges inward. If the stress continues, the leaves dry out and turn crisp from the tip, then drop, followed by flowers and fruit.

The guide says mature citrus trees use about 60 inches of water a year. Depending on the size of the tree, that can mean as little as 17 gallons a day in winter or as much as 135 gallons a day in summer. Grapefruit and lemons use about 20 percent more water than oranges, and mandarins use about 10 percent less.

The extension does not recommend watering every day, even though it measures water use in gallons per day. Frequent, shallow watering may leave part of the root zone dry and can build up salt in the soil. Instead, it says to wet the soil from the trunk to just beyond the drip line, to a depth of at least two feet, and to let the top six inches or so dry out before the next watering.

For October and November, the extension’s schedule suggests watering trees three years or older every 14 to 21 days. Trees one to two years old get water every 10 to 14 days, and trees four months to a year old every five to 10 days. From December through February, mature trees stretch to every 21 to 30 days. The guide says to choose the shorter interval for sandy or gravelly soils and the longer one for heavier clay, and to water more often in unusual heat and less often after rain. Trees three years or older on drip or microsprinklers should follow the schedule for a four-month- to one-year-old tree under basin or flood irrigation, since those systems put out less water at a time.

Fertilizer timing, and when to hold off

Fall is mostly a time to put the fertilizer bag away. The extension’s Citrus Fertilization Chart for Arizona splits a tree’s yearly fertilizer into three equal portions. For oranges, tangerines and grapefruit, those go down in January to February, March to April, and May to June. Lemons and limes follow a slightly different calendar, with portions in January to February, March to April, and August to September.

So for most backyard trees, the next feeding is in January. The chart also adjusts amounts by type. Grapefruit and pummelo get half the chart amount each year, and lemons and limes get about 10 percent more. The extension says to measure the fertilizer carefully, work it into the soil, and water it in.

Getting ready for cold nights

Winter is the other reason a fall class is well timed. The extension’s guide to protecting citrus from cold, also by Wright, notes that citrus trees are not particularly cold hardy and that frosts are more common than freezes in Arizona. It lists site selection, choosing the right variety and rootstock, and letting the tree acclimate to cooler weather as the most important defenses. Covering a tree, adding heat or irrigating may also help during a cold night.

The guide says citrus can be grown in some parts of Pinal County with good cold-air drainage, while low-lying spots where cold air settles are riskier. It also recommends checking temperatures in your own yard rather than relying only on the forecast, since a home can be several degrees warmer or colder than a reported reading. And if a tree does get frost damage, the guide advises waiting until spring to prune it.

Before you go

The Citrus Success class starts at 10 a.m. on Saturday, Nov. 7, at Desert Horizon Nursery, 19250 S. Ellsworth Road in Queen Creek. The houseplant class follows at the same time on Nov. 14. Both are free, and the RSVP forms are on the classes and events page at deserthorizonnursery.com.

The University of Arizona guides mentioned here, Irrigating Citrus Trees, the Citrus Fertilization Chart for Arizona and Protecting a Citrus Tree from Cold, are free on the Cooperative Extension website at extension.arizona.edu. Reading one before the class is a good way to arrive with sharper questions, especially if your tree has been blooming at odd times.