Who says Southern California doesn't have seasons?

As shoppers head for the mall and commuters make their way to the office, they are beginning to notice something New Englanders and Midwesterners feast their eyes on regularly -- brilliant autumn color.

Perhaps no tree is more brilliant at this time of the year than the widely planted sweet gum, which can be found in yards, parks and street landscapes everywhere from the cool, moist coast to the hot, dry inland valleys.

Picturesque groves can be found along Gird Road in Fallbrook, Aviara Parkway in Carlsbad and in the Bear Creek area of Murrieta, among other places.

Hard to miss, the five-pointed, star-shaped leaves of the sweet gum -- or Liquidambar styraciflua, as it is known scientifically -- are turning bright yellow, orange, red and purple.

"They're doing their thing right now," said Roger Boddaert, a Fallbrook landscape designer and arborist known locally as the "Tree Man of Fallbrook," for his efforts to preserve and plant oaks, in a telephone interview last week.

Sweet gums and other deciduous trees are giving residents a taste of fall, sprinkled among the perpetual green of the palms and tropical plants that permeate the artificial urban landscape.

In that sense, Boddaert said, Southern California's annual experience with fall color is wholly unlike that of New England or the Midwest. There, entire fields and towns are filled with deciduous trees, and they explode all at once in vibrant hues.

On the other hand, Californians enjoy a longer fall-color display because the area's steadier, warmer temperatures allow changing leaves to hang on for many weeks, said Dave Ehrlinger, horticulture director for Quail Botanical Gardens in Encinitas.

"I've always been amazed since I moved here at how long the fall color lasts in San Diego," Ehrlinger said. "The colors don't stick around as long back East, because a hard freeze comes along and the leaves fall off."

The sweet gum is actually from the East. Also commonly known as liquidambar, it is a native of the Atlantic seaboard and the Midwest from the Ohio River valley south. It also grows naturally in the cloud forests of Central America.

The fast-growing, pyramid-shaped tree has proven particularly adaptable to Southern California's warm climate and is one of the most popular choices of local landscapers and backyard gardeners.

It is prized locally, said Tineke Wilders, a garden columnist for the North County Times, because its colorful, star-shaped leaves remind people of the iconic maple of New England.

But the tree does come with some baggage, Boddaert said.

For starters, he said, the sweet gum has invasive surface roots that break up sidewalks, patios, pool decks and streets, if grown too close to them.

"Some people think they are offensive because they litter," he added. "And they can be."

Besides its color, the sweet gum is widely known for the spiny, golf-ball-sized seed pods it produces in huge quantities and sprays across yards.

"They can be hazardous to people walking under them," Boddaert said. "They are slippery."

And Ehrlinger, of Quail Botanical Gardens, said it isn't exactly pleasant to accidentally step on a pod while walking barefoot.

"The seed pods are shaped like medieval mace weapons," Ehrlinger said.

Another knock against the tree is its ability to grow -- in a relatively short time -- to as tall as 80 feet or higher. He said it can easily overwhelm a garden.

Another downside, Ehrlinger said, is its propensity to suck up huge amounts of water. That doesn't make the tree the most appropriate choice for a garden or yard at a time when the region is grappling with a crippling drought and trying to conserve water.

"They are really big drinkers," Boddaert said. "It's the nature of the beast. They are just drunkards."

For all its flaws, though, Wilders treasures the sweet gum because it is one of the most beautiful trees in Southern California today and one of the best sources of autumn color.

"When I moved to San Diego and did a lot of bicycling around town, I encountered the sharp spiny seed pods getting stuck in my bicycle tires," Wilders said by e-mail. "But in spite of that, I always enjoy this cone-shaped deciduous tree, with its maple leaf-shaped foliage and its typical fall color display. Enjoy it while it lasts."

Contact staff writer Dave Downey at (760) 745-6611, Ext. 2623, or ddowney@nctimes.com.