Fall is coming, and with it the promise of brightly colored fall foliage. But let’s face it: throughout most of California, fall color can be hard to find. Transplanted Easterners nostalgic for the psychedelic red, orange and yellow hues that cover autumn trees in Vermont and Virginia can find themselves at a bit of a loss come fall. Most California trees don’t do that.
It's not that there isn't fall color in California. It's just that it's not ubiquitous, the way it is in exotic foreign locales like Pennsylvania. Back east, you don't need tips on how to find fall-colored foliage for your viewing pleasure: you basically just need to go outside. Here, you often need to spend a little time thinking about where you're going in order to find those seasonal reds and yellows.
The reason? It’s the same thing that brings those transplanted Easterners to California in the first place: our mild weather.
Back east, deciduous trees have had millions of years to adapt to the pronounced seasonal shifts in that part of the world: warm summers alternating with prolonged, freezing winters.
During the spring and summer, the leaves of Eastern deciduous trees work to turn sunlight into sugar, using the molecule chlorophyll – which gives leaves their green color. Chlorophyll breaks down when exposed to sunlight, so the leaf cells have to replenish it continuously. When those trees decide it’s time to start preparing for winter, they shut down the photosynthetic factories in their leaves and stop making new chlorophyll. The remaining chlorophyll breaks down, and the leaves lose their green color.
With some trees, losing their chlorophyll allows the yellow and orange pigments (called xanthophylls and carotinoids, respectively) already present in the leaves to be plainly visible. Those pigments are thought to aid in light absorption to help regulate photosynthesis, and they’re there all summer: the chlorophyll just overwhelms them. Once it’s gone, the yellow and orange shine through.
If a tree develops red or purple fall color, that means its leaves have turned some of the remaining sugar in the leaves to a class of pigments called anthocyanins, the purpose for which is not well understood.
Whatever palette of pigments the leaves possess, the process is timed to coincide with the onset of the East’s relatively harsh winters. California, by contrast, has relatively mild winters due to its Mediterranean climate. Thus many of our native trees don’t ever change color. In fact, some of our trees, live oaks being an example, don’t lose their leaves in winter at all. Others, like the California buckeye, actually grow new leaves in fall and winter, shedding them with the onset of the dry season in late spring.
But there are exceptions. Some parts of California get colder in the winter, while others may be home to plants whose ancestors evolved the autumn leaf trait somewhere else and brought it here with them as they migrated. And still others are plants we humans imported from other places.
With that science in mind, there are a few basic strategies that would-be leaf-peeping Californians can follow to get their fall color on. The first one involves finding those places in California that have cold winters.
Head for the Mountains
In California’s taller mountain ranges, the trees and shrubs are accustomed to much colder winters than their counterparts at sea level. And that means you can often find pockets of brilliant fall color in the mountains. In more humid areas like the west side of the Sierra Nevada, vine maples can offer some of the most brilliant red leaves to be found in California in any season, while their cousins the bigleaf maples provide tall yellow beacons. The same places that harbor vine and bigleaf maples also often host Pacific dogwoods, whose leaves turn a deep wine-red.
Among California’s deciduous oaks, the valley oak and the black oak add more yellow to the forest, with an occasional black oak deciding to be a nonconformist and turn red. Blue oaks are more subtle, showing a brief orange tinge as they turn from green to brown.
Farther uphill, aspens can provide a startling display of bright yellow, with entire groves turning the same shade all at once. (That’s usually a sign that the aspen stand in question is a clonal colony all descended from the same seed, and connected at the roots.)
The aspens’ close cousin the cottonwood turns a similar yellow, and can be found along streamsides and in wet meadows throughout the western foothills of the Sierra, and along rivers in the Central Valley as well.
If you want to spend a few days among the changing leaves, just about any of the trail-equipped rivers and creeks draining the Sierra Nevada’s East Side will offer you some aspen leaves, as well as willows and other shrubs that share the leaf-changing habit with their taller cousins. Closer to Los Angeles, the state’s southernmost aspen grove is a short day-hike away from the Heart Bar Campground southeast of Big Bear in the San Bernardino Mountains. This grove burned in 2015’s Lake Fire, but at last report the resprouted aspens had reached six feet in height, and are no doubt readying themselves to turn yellow. (As the grove is in a recent fire area, check with the San Bernardino National Forest to find about about safety closures, and be sure to obey warning signs if present.)
If you’re more of a car potato, cruising the pavement between Lake Arrowhead and Big Bear will likely find you some foliage color. There’s also Frazier Park, on the slopes of lofty Mount Pinos; Tehachapi, whose encircling slopes reach around 5,000 feet; Wrightwood and environs in the San Gabriels; and easily reached parts of the San Diego backcountry like Julian. Cuyamaca Rancho State Park boasts a nice spread of black oaks, in case you’re jonesing for some yellow.
A valuable tip: The California Fall Color website and its volunteer army of color-spotters provide a frequently updated guide to great viewing opportunities throughout the state, with lots of reports from the state’s mountains. They also maintain this regularly updated Google map of California foliage color reports:
Head for the Hills
You needn’t have a tall mountain range in your plans to enjoy some fall color: the local small mountains will often do nicely. Even without deciduous trees, native shrubs can offer some pleasing fall color.
First among these, a personal favorite: poison oak. This close relative of eastern poison ivy turns one of the prettiest stoplight reds in the California foliage catalog, and if there was ever a plant that needed a stoplight, this is it. Pretty much any exposed area or open-understoried forest below 5,000 feet will have some of this plant, which (for those new to being outdoors) can raise seriously unpleasant welts on any bit of you that it touches. Whether it’s a ground cover, a stout shrub, or a vine climbing a hundred feet into a tree – and it does all three of those things -- stand back and admire those anthocyanins.
The related but less provocative skunkbush, a.k.a. Rhus trilobata, turns a similar red in fall, without the unpleasant dermatitis to go along with it. But it strongly resembles poison oak, so play it safe.
In coastal shrub thickets in the northern part of the state, shrubs like Mahonia, Oregon crabapple and black hawthorn often provide flashes of color in the red-to-purple spectrum.
Closer to Los Angeles, if you don’t insist on your fall color coming from leaves, the native shrub toyon starts putting out its bright red berries in fall and early winter, while the winter bloom of California fuchsia (Zauschneria or Epilobium, depending on which botanist you ask) provides bright red tubular hummingbird flowers that brighten up many of California’s droughty tan slopes.
Lastly, the state’s native grape, Vitis californica, often found as an understory plant in open woodlands or along forest clearing edges, mellows into a pale yellow foliage accent in autumn.
None of which is to say there aren’t trees in them thar hills. The California black walnut, favorite of squirrels throughout the state, puts on a spectacular display of fiery orange in good years. Even in a drought year like this one, in which trees tend to show slightly less color for a shorter time than average, finding a black walnut and watching it is a good bet.
Again, the California Fall Color website is a great guide to specific locations as they start to show color. Or just head out onto the road and see what serendipity brings you.
Run for the Desert
This may seem counterintuitive, as deserts aren’t generally known for their huge forests of deciduous trees. But seeps, springs, and ephemeral rivers in the California desert do host their share of cottonwoods, willows, and other yellow fall foliage plants.
Which means that you can enjoy fall color in Death Valley, if you time it right.
In parts of the desert with no deciduous trees, there’s still color to be found. The common California interior buckwheat, a low rounded shrub that bears white or pink flowers in spring, holds onto those flowers until they’re fertilized, turned into fruit, and ripened with fertile seeds. The result – rust-red seed clusters resembling dried flowers – can carpet whole swaths of desert valley floor, especially in the juniper sections of the Antelope Valley. Its cousin desert trumpet, mainly notable for its oddly swollen flower stems, turns those stems a deep burgundy-brown in fall.
One of the most unusual fall color sources in the desert comes from a vegetative interloper: the often maligned tamarisk tree. When it starts getting cold, generally in October in the high desert, tamarisks can turn a number of colors from a clear yellow to a pale orange. Sometimes they just turn tan. It’s the luck of the draw. Look for them along desert watercourses like the Mojave River or the banks of the Colorado, as well as in places where they’ve been planted as windbreaks.
Down on the Farm
Not all of California’s fall color is found out in the wildlands, or from native plants. For instance: more than 1,400 square miles of California is planted in domestic grapes. Many of those grapes are located in undeniably attractive settings such as rolling hills backed by live oaks or conifers. Whether the grapes are destined for the table, a wine bottle, or a raisin drying rack, the vines they grow on are a reliable source of brilliant red to purple fall foliage.
Sadly, the state’s burgeoning crop of almonds doesn’t add much to the state’s fall colorscape: the trees’ light green leaves turn a light greenish yellow, then brown. But other deciduous orchard trees are more accommodating to the foliage viewer. Pomegranates’ complex leaves turn a bright yellow. Pistachios go startlingly red. Apple trees, in case you’re within striking distance of Sonoma County, turn more or less yellow. Stonefruits like peaches, plums, and pluots span the spectrum from orange through red to purple. Persimmons are bright red.
An orchard or vineyard is not going to be the most naturalistic of settings – and unless they specifically invite you to stroll through the trees or vines, most growers take a dim view of trespassers, leaf-peeping or otherwise. But finding row upon row of bright red or yellow trees in geometric lines heading toward the vanishing point can be pretty rewarding.
Hit the Streets
Or, you could just stay home. California’s cities tend to have far more fall color-bearing plants than most other places in the state. Angelenos have imported, for good or ill, a huge range of plants from all over the world that show reliable fall color. There’s the ginkgo, an Asian plant with no close living relatives but distantly related to conifers. Its ancestors’ leaves have been found in fossils 270 million years old, and you can find modern day ginkgos throughout urban California. They work well as street trees, growing slowly and tolerant of pollutants. On occasion you’ll fins a century-old specimen in a favored spot somewhere. There are few purer yellows in the world than the yellow found in an autumn ginkgo leaf.
Another common street tree is probably on its way out: the ubiquitous liquidambar or sweetgum, native to the forests of the southern East Coast states, has long had a bad reputation for its disruptive root system. The tree’s roots can break up sidewalks, make lawns unwalkably corrugated, and invade sewers and other utility pipelines. They also turn brilliant yellow-speckled red in fall, which is why they were planted in California in the first place. Since 2000, the trees have contended with a worse foe than angry homeowners with chainsaws: the glassy-winged sharpshooter, a insect pest that spreads a bacterial disease among the trees. Enjoy their color while you can.
The list of potential fall color-bearing trees and shrubs in California streetscapes is forbiddingly long. There are Japanese maples. There are the above-mentioned fruit trees, as well as non-fruiting fruit trees like the (also ubiquitous and much-maligned) Bradford pear. (Red leaves in fall.) There are red Chinese pistaches and yellow sycamores and red-orange crape myrtles. There are too many, really, to mention without resorting to bullet points. A visit in season to the Los Angeles Arboretum or Huntington Gardens can reward you with some pretty darn good autumn hues.
Or, you know. Just go outside.