In the Garden Articles

Fall Color

by Joan S. Bolton

An honest look at the liquidambars around town, rich in their fall glory, should be enough to convince even the most die-hard Easterner that fall color is alive and kicking on the Central Coast.

To be sure, our urban forest can't compete with the brilliant yellow aspens in the Rockies or the scarlet maples in the Northeast. But we can still savor a few brightly hued, deciduous trees that mark the changing seasons.

Fall is a great time to select fall-foliage trees. Coloring often varies from one tree to the next. By shopping now, you'll see exactly what you'll get. Be sure to check the branching structure underneath. After that stunning foliage drops, all you'll see until spring is a criss-cross of bare branches and twigs.

Here are some of the most glorious:

Japanese maple (Acer japonica) is a fabulous exception to the rule that maples don't grow well in mild climates. Hybridizers have worked their magic on these dainty trees, creating endless variations of leaf color, leaf structure and overall size. Choosing yours in the fall ensures that you'll get one that produces fall color. A few hybrids turn a muddy brown before their leaves drop.

In the garden, shelter your Japanese maple from heat and dry winds. Good options are beneath a tall tree or on the east side of your house, which offers protection from the afternoon sun. Also, Japanese maples like lots of water and do well planted next to lawns.

Smoke tree (Cotinus coggygria) may be best known for its thready blossoms that appear like smoke puffing above its round, bluish-green leaves in spring and summer. But in fall, long after the puffs have dissipated, the leaves of the straight species turn yellow, orange and red. Meanwhile, a popular burgundy variety, Royal Purple, holds its dusty purple leaf color through spring and summer, then shifts to deep red.

Smoke tree grows slowly to form a multi-trunked, rounded tree about 25 feet tall, and does best in dry, well-drained soil.

Oriental persimmon (Diospyros 'Fuyu' or 'Hachiya') is worth growing for its stunning fall show, even if you never nibble the fruit. One of the Central Coast's most consistent fall color trees, its oval leaves turn orange, yellow and scarlet, while miniature pumpkin-like orange fruits hang on for weeks. When all drops, the horizontal branching structure is beautiful in its own right.

Fuyu bears persimmons that are harvested and eaten while crisp, while Hachiya's fruits are entirely too puckery until they're overly ripe and soft. Both types eventually reach about 30 feet tall, with a rounded shape. You can trim them for smaller spaces.

Maidenhair tree (Ginkgo biloba) is another reliable fall-foliage tree, with golden fan-shaped leaves that hold their color even after they flutter to the ground.

Ginkgos are slow to get started and often have an awkward shape early on. But eventually they sort themselves out and reach 35 to 50 feet tall. Heavily fissured bark covers their stocky trunks. They are excellent lawn trees.

The common name, maidenhair tree, refers to the soft, spring-green leaves that start out papery, then thicken and darken with age. The tree is also sometimes referred to as the dinosaur tree. That name relates to fossils dating 250 million years old that bear the imprint of the distinctive leaves.

Chinese flame tree (Koelreuteria bipinnata) might not officially be a fall-color tree because it's the seed pods, not the leaves, that put on the show. The dangling pods look like small, papery lanterns as they intensify in shades of salmon, red or orange before fading to tan.

Chinese flame tree grows relatively quickly to 35 feet tall and forms a broad canopy. Its roots are not aggressive. It does well next to patios, driveways and sidewalks. Smaller shrubs, perennials and annuals will grow beneath it.

Crape myrtle (Lagerstroemia) may have just finished blooming. But it's already on to the next phase of its cycle: of dropping its flowers and shifting its leaves to deep purple or orangish-red.

Once bare, you'll see brown and gray bark that twists, shreds and exposes fresh pink bark beneath. Most crape myrtles top out at 25 feet. They may also be grown as large shrubs.

Sweet gum (Liquidambar styraciflua) grows fast, easily scaling 45 to 60 feet. That it was a favorite street tree decades ago has come back to haunt certain neighborhoods, where its notorious surface roots have wreaked havoc with sidewalks and driveways. The spiky seed pods, nearly the size of ping-pong balls, can be a nuisance as well.

But plant your liquidambar in the proper spot and it will provide a beautiful focal point for tracking the seasons. This time of year, the leaves are shifting to brilliant red, yellow, orange and burgundy. Those leaves drop at the last possible moment, so there's lots of fall color and just a brief period of bare over winter. Come spring, the new leaves emerge a vibrant green, then stay a deep green during summer.

Chinese pistache (Pistacia chinensis) turns psychedelic shades of hot pink, fire-engine red, brilliant yellow, crimson and orange -- often all on the same tree, and even in the mildest of areas.

A popular street tree, Chinese pistache forms a rounded dome of drooping, frond-like leaves that grows more than 30 feet tall. It's quite accommodating, settling for everything from a wet zone next a lawn to the driest spot in your garden.

Purple-leaf plum (Prunus cerasifera) already bears purple leaves. But in fall, the leaves turn an even more dramatic shade of heavily saturated, dark purple.

This is one of my favorite trees for contrasting leaf color with other more traditional green trees in the garden. It's also one of our fastest growers, reaching 18 to 20 feet tall and 15 feet wide in just five years from a 15-gallon container.

Like Chinese pistache, purple-leaf plum tolerates nearly every soil and watering regimen.

Chinese elm (Ulmus parvifolia) is somewhat a chameleon. In mild areas along the Central Coast, the oval leaves of these graceful, weeping trees turn yellow. But in colder, inland regions, the leaves shift to orange or red. Chinese elm grows fast, quickly reaching 50 feet or taller, while spreading just as wide.

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Why Do Leaves Change Color?

The changing of colors is the response of many a deciduous tree to the onset of winter.

Before its leaves drop, the tree goes into overdrive, converting the starch in its foliage to sugar, to store in its branches and trunk as reserve energy for sustenance over winter.

But nippy nights interfere with the process, preventing the leaves from sending the sugars into the tree. The sugar buildup often appears as a red pigment.

At the same time, the green in the leaves -- the chlorophyll -- breaks down, revealing any other pigment in the leaf, which may be red, yellow or orange. The resulting mix of stalled sugars and pigments is a delight to the eye.

Weather weighs in, too. A good scold snap heightens the hues while mild weather dulls them. In your own garden, your best fall color will likely be in a low spot where the cold settles at night.

Strong, afternoon sun can intensify colors as well, even to the point of causing the southwest side of a tree to sport more vivid color.

Seeds of Wisdom

Plant a deciduous tree this time of year and it will soon drop its leaves. But below ground, its roots will be venturing into your garden soil. By next spring, it should be poised to support robust new growth.