Few sights are more inspirational than a yellow blanket of wild mustard splashed on a California landscape in early spring.

"If you go up the 5 (Interstate 5) in early spring, the yellow Bermuda buttercup on the hillsides is just gorgeous to me," said Cheryl Wilen, integrated pest management adviser for the University of California Extension service.

Inspirational? Gorgeous? Those are weeds! Weeds! The bane of the gardener, who each year is poised for a pitched battle against them: En garde! Choose your weapon! Charge!

But this year, before you go forth with the usual implements and poisons, let us hear what area garden experts have to say about weeds and how to deal with them.

"There are no weeds in nature," said Vincent Lazaneo, a horticultural adviser for the Extension program. "Our definition is it is something we don't want, so we call it a weed if it interferes with activity, like a stinging nettle or poison oak, or become fire hazards or competes with plants we want to grow. They grow so quickly, they compete for water, nutrients and space. They grab all the light and room before other plants have a chance to grow."

But weeds can be helpful in some respects, he said. They protect the soil and keep it from eroding away into a gully or storm drain.

"We are blessed with two crops of weeds, one during the winter and one during the summer," Lazaneo said. "If you want to avoid winter weeds, you will have to move to Chicago, where it snows."

After the recent rains, the weeds most gardeners are seeing include clovers, common groundsel, annual bluegrass, mallow and filaree.

Mallow gets to be about 5 feet tall with big circular flowers if unchallenged. Filaree grows close to the ground, almost like a fern leaf. When the seeds mature, they are hard. Shepherd's purse also grows close to the ground and has a little triangular seedpod that is kind of hairy and sticks to people's socks, Wilen said.

"There are a lot of thistles and dandelions," Lazaneo said. "After they reach a certain size, they send up their flower stalks and have a bloom, and seeds are carried off in the wind. If you want to try to control weeds, you want to keep them from spreading their seeds."

There are ways to prevent weeds, he said. One is to cover the garden area with a thick layer of mulch so that the sun cannot reach the ground underneath to cause weeds to grow.

Or put down a layer of weed-blocking fabric that lasts for a number of years. These fabrics, also called geo-textiles, are available at garden centers and home improvement stores. They can be covered with wood chips or decorative crushed rock and the like. Gardeners can put them around existing plants and keep the weeds from growing from underneath, so they do not have to keep constantly battling weeds.

If you have an established lawn, and it's growing a good, thick, healthy grass, it is hard for weeds to establish themselves. Just regular mowing controls a lot. Use fertilizers to help develop a good root system before summer, Lazaneo said.

Wilen also suggests a natural way to reduce weeds that she called: "Water. Wait. Cultivate."

What she means is that gardeners should allow weeds to come up in their plots and then get rid of them before planting that season's crops or flowers. This can be done a couple of times during the growing season, but she advises doing a shallow cultivation because you don't want to bring up weed seeds that are buried deeper.

A number of chemical products are also available, including pre-emergent herbicides, which are sprayed on ground before weeds can sprout, or products like Round-Up that kill existing weeds. Lazaneo encourages those who opt for these products to read the fine print, because too much of a good thing can be a bad thing, he said.

For more information about weeds, visit www.ipm.ucdavis.edu.