The Arizona mountains, called “Sky Islands,” are home to plant species one may never expect to find if they were to remain in the desert valleys. Going up in elevation demonstrates a similar effect as going up in latitude. Colder and wetter weather modifies the plant communities, and there are clear observable ecosystem transformations every few hundred feet of elevation change. Mt. Lemmon, towering above Tucson, was my first foray into the sky islands (2021). Every ten feet we drove up the mountain I wanted to stop and look and study. But I don’t just want to look when I get to this state. I wanted to gaze. It is essentially impossible to satisfy my need to gaze at these landscapes, absorbing hidden information of the land and its complex transformation, balance, and beauty, dreaming of future gardens I would like to design, mimicing the plant pallets found in these diverse western wonderlands.
Beginning as desert valley, with one of the most amazing displays of Saguaro cactus, the desert transforms at 4500’ elevation into a landscape reminiscent of Southern California. Oaks begin to dot the landscape in a savannah full of abundance. Quercus oblongifolia, the Mexican Blue Oak, gorgeous and glowing with its evergreen, oval shaped, glaucous blue leaves is among the first to show up, along with Quercus emoryii, intermixed with Arctostaphylos, Frangula, Garrya, Juniperus, Baccharis, grasses, agaves, and yuccas. A few feet higher in elevation and Quercus arizonica shows up, similar in color to Q. oblongifolia but with slight wooly pubescence on the leaf surface, and an indumentum on the bottom side of the leaf, plus Frangula, and ferns!
Further along up the mountain, Quercus hypoleucoides the silver leaf oak, and Quercus rugosa the netleaf oak appear, continuing onward up to the highest elevations of the mountain as the other oaks fade away. But it isn’t just an oak tree game - at higher elevations, species familiar to Pacific Northwest native plant gardeners begin to show up - snowberry, oregon grape, currants, firs, maples, aspens! It was the snowberry that I saw as we turned a corner on the upper elevations of Mt. Lemmon that truly unveiled the potential for harmonious unity between our PNW ecosystems and the beautiful and resilient species of Arizona.