Did you know there is something to eat almost any time of the year on the grounds of Boyce Thompson Arboretum? We strongly discourage grazing the wild or cultivated plants at the Arboretum (in fact, it’s a big No No), but it’s still comforting to know that if marooned on the grounds, a person could survive for two or three days without significant weight loss.
I know this to be true because I have been recording the times that the Arboretum’s plants flower and fruit for more than twenty years. And I have a stack of 50 dog-eared pocket notebooks full of these notes to prove it. Even though every year is unique, two decades of recording have allowed me to make some pretty reliable generalizations about fruiting times.
Grazing in the grass is a gas
In May, saguaros begin to flower (a fitting tribute to Mother’s Day), and mom can get a rare, eye-level close-up of them at the seating area on the Main Trail just outside of the Visitor Center. If she looks at them long enough, the pollinated flowers will gradually become sweet edible saguaro fruits by the time Father’s Day rolls around in June.
The ‘Black Mission’ fig trees across from the Herb garden are as regular as an atomic clock, with the first crop of figs produced in early June. Two weeks later, the tan-colored, gumball-size fruits of the chanar (Geoffroea decorticans) in the Asian Desert exhibit have fallen to the ground by the thousands, a drop-dead lookalike of a gumball hail storm.
Back by the fig tree, there are two low-chill apple tree cultivars (‘Anna’ and ‘Golden Dorsett’) that reliably produce mature fruit in the summer heat of early July. Alongside is a ‘Santa Rosa’ plum with fruit that ripens about a week afterward. About the same time, a native Arizona black walnut (Juglans arizonica) near the narrows along Queen Creek, drops pin ball size walnuts wrapped tenaciously inside a thick, green husk.
Some like it hot
August is the month for the wine-colored (and spine covered!) fruits of the native prickly pear (Opuntia engelmannii) to ripen. They are ubiquitous throughout the grounds, especially in our native, uncultivated areas. Another pear shaped fruit that ripens in August is the jujube or Chinese date (Ziziphus jujuba cv.) that grows from the trees in the Asian desert exhibit along the main trail. These dry-ish but tasty fruits have the texture of a mealy apple (in a good way) that become chewy and date-like as they mature. They start off as yellow-green and gradually transition to a shiny chocolate color as they ripen.
As long as it’s still August, retrace your steps to the fig trees across from the Herb Garden and you’ll find the second crop of ‘Black Mission’ figs. This fig cultivar produces two crops a year, one on last year’s wood in June and another on the current season’s growth in August.
Another late summer producer is the date palm, Phoenix dactylifera. This tree has been cultivated for at least 5,000 years, but only a mere 75 of them at the Arboretum. Only the female plants produce fruit, and only if the flowers are well-pollinated, most reliably done by hand. Without a thorough dusting of pollen, all those big plump sweet fruits from the two female trees across from the Herb Garden and a few other locations around the grounds will fail to develop.
The summer monsoon usually ends in mid-September, about the same time that the pumpkin-orange (and pea-sized) fruits of the native desert hackberry (Celtis pallida) are ripening. The fruit of this thorny, unassuming shrub is not just another sweet incredible edible for us, it is one of the most important bird plants that we have on the grounds. Some of the largest plants are near the picnic area and in the Australian Desert Exhibit.
Sometimes the flowers and the fruits are edible
A small, little known tree that not only has edible fruit but also edible flowers is the pineapple guava (Acca sellowiana). There is a single tree tucked away in a quiet little corner of the Herb garden and another half dozen planted as a hedge in the Demonstration Garden. The minty-tasting flowers come in May; by October, football-shaped fruits with a dull-green, leathery rind are dropping to the ground, sometimes all the way into November. By this time, the edible pecans from the large tree against the cliff in the herb garden have fallen, but you have to get to them before the rock squirrels bury them for their overwintering stash.
What really tides us over during the cold winter months are the numerous citrus trees throughout the grounds that ripen in December and January with fruit that can stay on the trees for months afterwards (if the birds don’t peck them first). We have grapefruits, tangerines, tangelos, ornamental oranges, and small odd-ball citrus with a thin edible skin called a limequat.
In the Mediterranean Desert exhibit, overripe black olives can be raining from our venerable old olive trees during the dead of winter and squished by the thousands on the Main Trail by February. In November, though, they are still green and astringent to the taste and ready to be picked for curing. A few weeks later, when they develop a purplish blush, is the best time to press them for olive oil.
Late February and early March mark the beginning of the spring season with a flurry of flowering and new growth. There is still some of last year’s citrus hanging from the trees; there is plenty of miner’s lettuce (Montia perfoliata) with its edible leaves along the shady and moist parts of the High Trail; and the native tomatillo (Lycium sp.) can be counted on to produce a mid-spring crop of sweet red fruits that are my personal favorite Sonoran Desert fruits to munch on.
Over the years, the daily exposure to the Arboretum’s plant collection has cultured a satisfying feeling of familiarity and intimacy, like an old friend—a friend that invites you to dinner. But sometimes, even friends disappointment. So I pack a lunch. And so should you.