Autumn is a stunning season here in Canyon Country. The warm temperatures may last long into the season depending upon the arrival of early winter storms. As the daylight hours shrink and the nighttime temperatures get cooler, this translates into a colorful change to the plant landscape.

This stunning transition is marked by the native deciduous trees: oaks, cottonwoods, aspens, hackberries, and willows but some of the shrubs also contribute to this mosaic of color in a Crayola moment.

In terms of this splash of color, it is the pigments within the leaves that are responsible for the various hues in the leaves. The green chlorophyll pigments dominate throughout much of the season, and contribute to the photosynthetic process that powers the plant. As temperatures fall and daylight hours decrease, these environmental factors collide with other age-related aspects of the plants resulting in the chlorophyll pigments breaking down. This aging sequence of the leaves is called “senescence” and results in the fall of autumn leaves.

As the chlorophyll breaks down, other pigments in the leaves become exposed. These unmasked pigments produce various colors from yellow to red, with shades in between. Along with this process of deterioration, cells at the leaf bases also begin to change These abscission cells are like the guardians at the gate, they shut the doors to protect the rest of the castle.

Cloaks of gold wrap themselves around the La Sal Mountains, the Abajos, and other ranges in the region as swaths of aspen turn color in the autumn sunshine. The gold is a stark contrast to the dark green evergreens, the firs, spruces, and pines that maintain their color throughout the season. An occasional dot of orange or red might be present in the aspen groves, but these colors are often hidden by other pigments in the aspen leaves.

Another higher elevation plant that contributes to the color scheme taking place, is the Gambel’s oak. A drive across Soldier Summit north of Price or up to Geyser Pass in the La Sals, traverses through groves of gnarled oaks bearing their burnt sienna splashes of color. These trees seem out of a Tolkien story, their twisted and turning trunks and branches seem to freeze frame a frenzy of action. As the trees lose their leaves, they expose the creatures that root through their litter for acorns such as black bears, mule deer, wild turkeys, and other animals.

Down from the mountains, in the redrock canyons etched across the desert, the streamside or riparian vegetation is often dominated by Fremont’s cottonwood or coyote willows. In fall, these plants produce golden ribbons of color that follow the canyon meanders. Some of the cottonwoods may have massive trunks and these have withstood decades of flooding. The fluttering cottonwood leaves, born on long petioles, resemble their relatives the aspens; both are members of the Populus genus in the willow family.

The willows growing along the stream beds also get in on the color scheme, along with other shrubs and small trees such as three-leaved sumac, wild rose, single-leaf ash, and netleaf hackberry. Non-native plants such as tamarisk and Russian olive also turn shades of yellow and are often mixed in with these native riparian plants.

As long as the temperatures stay reasonable and winter’s icy fingers don’t rake through the trees, the procession of color during the fall is a long one and offers ample opportunities to witness this parade of color before the season changes.