Nematodes are especially active in warm weather. These microscopic worms bore into roots of susceptible plants, causing galls and knots and weakening the plants. Here are two ways to significantly reduce large populations of nematodes.

Solarize the Soil:

Solarization--using the effects of the sun's rays--is the method to use only when nematode and fungus problems are acute and unbearable. It kills useful organisms, including worms and beneficial fungi, along with the bad ones. (This works best where summer days are hot.)

Pull out all the plants, including the roots, and thoroughly soak the soil with water. Cover the area with clear polyethylene plastic 1 to 4 millimeters thick. Prop up the top layer with wire hoops or bamboo frame, peg it down around the outside, and bury the loose edges.

Solarization works in the same way as a greenhouse where a transparent covering, in this case the plastic sheeting, traps the sun's heat. After several days of sunshine, soil temperatures rise to as high as 140 degrees at the surface and over 100 degrees as far down as 18 inches--hot enough and far enough down into the soil to sterilize it. It takes four to six weeks of sunny weather to pasteurize the soil at these temperatures.

Plant marigolds:

Many people think marigolds repel nematodes, but the truth is they attract them. Root knot nematodes entering marigold roots are killed by a natural plant chemical before they have a chance to reproduce. Marigolds can be used to rid the ground of these pests. In spring, solidly plant the area to be treated with French marigolds, placed in a 7-by-7 inch pattern. Leave marigolds in place for a full 120-day season of growth.

With either method, nematodes will gradually return, but they'll be discouraged if you regularly add an organic soil amendment such as Kellogg Nitrohumus. They don't like humusy soil.

At regular intervals our ocean dumps quantities of kelp on local beaches. Most beach-goers find it a nuisance, but some enterprising gardeners take a little home every time they go to the beach to improve their garden soil. All that's needed for gathering is a plastic trash bag, a knife, and a sense of humor. Kelp is tough, slippery and acts like giant spaghetti. Choose the juicy sections, not the dried out parts.

Once home rinse off the kelp on the driveway to remove salts. Chop it up with a spade or machete, and spade it straight onto the soil or add it to the compost heap.

Kelp,rich in trace elements, decomposes quickly in the ground. The ancient Romans worked seaweed into their fields before planting cabbages.

Looking for some trees that bloom in late summer? Here are a few suggestions:

Crape myrtle is an elegant drought-resistant tree for small-space gardens in interior valleys. (It gets mildew along the coast.) It blooms in white and electric shades of pink and red from July through August. Its lovely gray-brown bark peels off yearly to soft pink. Look for the plants while they're in bloom. (People either love or hate some of the colors.)

Among the cassias that can be grown here in Southern California, the gold medallion tree (Cassia leptophylla) is the most dramatic. It's best in a warm, sheltered spot and when watered deeply and infrequently, but it will grow in lawns if it has excellent drainage.

Along the coast flame eucalyptus (Eucalyptus ficifolia) can grow in the teeth of the wind and still bloom magnificently. Pick out the color now, if possible. (Young trees often won't bloom in the can.) The orangey red is beautiful viewed against the sea. Grow it with a single trunk, or, if desired, cut it back to make a huge, multi-branched shrub. It blooms on and off all year. The eucalyptus beetle prefers gum eucalypts and usually doesn't attack this unless it's under stress from drought.

In recent travels, I have been fortunate to visit some traditional Chinese gardens in the cities of Hangzhou and Suzhou. In both these cities the gardens are open to the public; however, they are within private homes and temples.

In China during the late Ming Dynasty, the home was a place where one could entertain colleagues and friends, and to have a garden demonstrated the status of the owners of the property. The first thing you notice about these gardens is that there are no wide open expanses; the settings are actually quite intimate. In each garden you get the feeling of being in a "garden room" and are led from room to room by a winding stone path.

Garden design is completely different in China than in traditional European gardens. There is a great emphasis on the symbolism and meaning behind everything in the garden. A garden designer looks to reproduce nature, not by imitating it, but rather by interpreting it, by creating a three-dimensional portrait. Shapes and masses such as blocks of stone or tree roots are used to achieve contrast and arouse emotion.

One of the most amazing things I encountered in a garden in the city of Suzhou was a formation of rocks made to look just like a mountain range, extending throughout the entire garden.

The design of a Chinese garden is greatly influenced by four major elements: plants, water, stones, and architecture. A lot of gardens look as if the designer was trying to take a really huge idea, and interpret it down into a size that could be contained within walls. For example, the "mountain range" stone formation and the water features in Chinese gardens make one think of a grand epic view of the mountains and water on a much larger scale. The design of the paths and the various "rooms" makes one feel as if they have just had a miniature tour of some of the breathtaking views of the real mountains and lakes in China.

The Chinese garden is a beautiful, magical, and peaceful place to be. If you are interested in having a little bit of China in your own backyard, just remember the importance of using the major elements: plants, water, stones, and architecture. In a Chinese garden beauty and "naturalness" are philosophies that lead to a successful garden design.

Thanks to guest writer Lisa Akiyama for this article.