What it means
Say mesquite in Scottsdale and you could mean four things, and the listener will know which from the setting. On a trail it is the tree: the velvet mesquite, a crooked, dark-barked, thorny legume with ferny leaves that lines every wash and gives the only deep shade the low desert makes on its own. In a kitchen it is the flour, sweet and nutty, milled from the bean pods. At a steakhouse it is the wood, the hot, fragrant smoke under the ribeye that the cowboy steakhouse tradition is built on. And in a yard it is the thing the landscaper planted that blew over in July.
The desert plants field guide calls it the shade tree of the washes, with the bean pods the Hohokam and their descendants ground into flour. That is the short version. The longer one is that mesquite fed this valley for a thousand years before the canals carried wheat, and that the tree is better at living here than anything people have planted since.
Where you’ll meet it
Along Indian Bend Wash and every natural wash in the Preserve, on the Salt and Verde where the bosques survive, labeled at the Xeriscape Garden, in the exhibits at the Huhugam Ki Museum, and on the menu at every steakhouse in the steakhouse guide.
Where the word came from
The word walked north with the Spanish. Mezquite in Mexican Spanish comes from the Nahuatl mizquitl, the Aztec name for the tree, and English speakers in Texas and Arizona respelled it. Botanists have been less stable: the tree was Prosopis velutina for a century and was recently moved to Neltuma velutina, a change that nurseries and most field guides have ignored. Three mesquites are native to Arizona. The velvet mesquite is the Sonoran one, centered on central and southern Arizona and Sonora; honey mesquite is the widespread Southwestern species; screwbean grows only along watercourses.
The tree’s importance is older than its name. At Snaketown, the great Hohokam village on the Gila, the archaeobotanist Vorsila Bohrer found mesquite seeds making up about two-thirds of the plant refuse, which means a people famous for canal irrigation still ate as much mesquite as corn. In 1871 Frederick Grossman, the federal agent at the Gila River reservation, reported the Akimel O’odham and Piipaash gathering millions of pounds of pods a year. The Tohono O’odham calendar names the June moon for the mesquite bean harvest. Pods were ground into pinole, drunk as atole, and pressed into shelf-stable cakes; the roots went into baskets and the sap sealed them. Mesquite flour, now sold at farmers markets, is 25 percent fiber and 13 percent protein with a glycemic index around 25, a fact nutritionists rediscovered a century after the government agents stopped counting pods.
The grilling wood is the Anglo contribution. Mesquite burns hot and long and gives off a sweet, assertive smoke, and the ranch cooks of the Southwest used it because it was what they had. When the cowboy steakhouses of Pinnacle Peak opened in the 1950s and 1960s, mesquite-grilled became the house style, and mesquite grilling has its own entry.
What it is not
Not an ironwood and not a palo verde, its two companions in the washes. Ironwood is gray and evergreen; palo verde has green bark and almost no leaves. Mesquite is the dark, shaggy one with real shade. And the thornless, fast-growing “Chilean mesquite” of Scottsdale subdivisions is a South American cousin or hybrid, not the native tree.
The fine print
Velvet mesquite grows 20 to 50 feet depending on water, and the Desert Museum’s care sheet says 20 feet tall and 30 wide is typical in a yard. It flowers in spring after leafing out, pale yellow catkins pollinated by bees, with a second bloom often following the monsoon, and the pods ripen tan with maroon streaks by midsummer. It goes bare in December and tolerates cold to at least 15 degrees, which is why it ranges higher than ironwood. It fixes nitrogen, nurses young cacti, and anchors soil along washes, where its roots average about 50 feet deep and have been recorded at 175 feet, the deepest documented for any tree.
That root is the Scottsdale lesson. The South American and hybrid mesquites that builders plant for speed and thornlessness never grow it, especially on shallow drip irrigation, and the Desert Museum notes that the native velvet mesquite is stronger-wooded and better-rooted with less chance of splitting or blow-down. Every July the monsoon manual could be illustrated with uprooted hybrids on their sides in cul-de-sacs. Deep, infrequent watering pushes roots down; daily drip keeps them at the surface.
The bosques are the loss. Where the Salt, Gila and Santa Cruz had shallow water tables, mesquite grew in true forests, and groundwater pumping and clearing took most of them in the twentieth century. The remnants along the lower Salt and Verde are the best place to see what a mesquite woodland was, and to collect pods in June if the Forest Service rules allow it that year. Harvest dry pods from the tree, not the ground, where they pick up mold; local groups run hammer mills each summer that turn a pillowcase of pods into flour in minutes.