Within the next month or so, warm-season vegetables will begin to succumb to cooler autumn weather and should eventually be replaced with cool-season vegetables. I prefer to wait as long as possible to maximize tomato production. Tomato vines eventually wither before the last tomatoes ripen. The largest of these green tomatoes ripen on the kitchen windowsill. Those that don't, get pickled. This unfortunately delays planting of cool-season vegetables and does not actually produce a substantial quantity of extra tomatoes.

Unlike warm-season vegetables that make up for lost time if planted too late in spring, cool-season vegetables planted too late in autumn are deprived of the "head start" they would get if planted while weather is still somewhat warm. This is because growth of warm-season vegetables accelerates in spring as weather becomes warmer, but growth of cool-season vegetables decelerates in autumn as weather becomes cooler. I don't care, because I prefer tomatoes to cabbage.

Those who enjoy cool-season vegetables may want to attend a class offered by Friends of Guadalupe River Park and Gardens regarding various vegetables that can be grown until replaced by warm-season vegetables next spring. Winter Garden Vegetables takes place from 10 to 11:30 a.m. on Sept. 18. Admission is $15.

On Sept. 15, a composting workshop conducted by master composter Phil Cornish will explain how to transform old tomato plants and other garden debris into compost that can be enjoyed by later generations of vegetables and throughout the garden. The composting workshop will be from 6 to 8 p.m. and admission is free.

Both classes are at the Guadalupe Garden Center, located at 715 Spring St. (at Taylor Street) in San Jose. Attendance is limited, so reservations should be arranged early by sending a check to Friends of Guadalupe River Park and Gardens, 50 W. San Fernando St., Suite 1100, San Jose, 95113. VISA and Master Card are also accepted. More information may be obtained by telephoning Kary Wilson of the Guadalupe Garden Center at 408.298.7657 or online at www.grpg.org.

Like tomatoes, roses will be less productive during autumn. In fact, the next rose deadheading in the San Jose Heritage Rose Garden will be the last until the more than 3,700 cultivars of roses wake from winter dormancy next spring. Volunteers for this event are so greatly appreciated that free ice cream sundaes will be served afterwards. Volunteers should bring their own shears if possible and will get any necessary instruction from experts.

The deadheading will be from 5:30 to 7:30 p.m. on Sept. 14. Guests will meet at the center of the San Jose Heritage Rose Garden, located on W. Taylor Street between Coleman Avenue (or Spring Street) and Highway 87. You can sign up or obtain more information by contacting Lucy Perez, who is also at the Guadalupe Garden Center.

Tree of the Week: Olive

Olives, Olea europaea, were among the first exotic (nonnative) species introduced to California by Spanish missionaries. The oldest of olive trees were originally grown to provide olive oil and some fruit. Those that most of us are now familiar with in the Santa Clara Valley are "ornamentals." Profuse fruit among such urban trees is only a purplish-black nuisance that stains pavement.

Older trees are messier because they were grown prior to the development of the contemporary "fruitless" cultivars. Younger fruitless trees are rarely completely fruitless but should produce only a negligible quantity of fruit. Those of us who want the fruit have unfortunately found that almost all olives have been infested with a host-specific fly larvae during the past few years. I am not yet aware of a remedy to this epidemic.

Some garden enthusiasts enjoy the light gray color of the foliage, and some find the gnarled and sculptural trunks and limbs to be appealing. Growth is slow, but mature trees may be as high and wide as 25 feet. Olive trees enjoy cultivated and irrigated gardens, but will grow almost anywhere that is sunny.

Horticulturist Tony Tomeo can be contacted at 408.358.2574 or at LGHORTICULTURE@aol.com.