I would not mind squirrels so much if they would be satisfied with the abundant acorns. However, they regularly abscond with fruit and flowers from the garden as well. In fact, the walnut tree has never provided me with a single walnut. Acorns, walnuts and pits from plums that can be stored for winter are buried mostly in planter boxes, where they, forgotten, later germinate. When I place seedlings in the garden, squirrels pull some of them up to see what I might have buried underneath—they perceive the soil disturbance as another squirrel's attempt to hide his stash.

Due to some unknown ecological disruption, squirrels and rats have been very prolific this year. I have not inquired with any extermination service to confirm my observations, but I have been receiving more email and telephone correspondence concerning rodents this year than I have received during the past several years combined. I have also found that much more fruit has been stolen from the several fruit trees in my mother's San Jose garden. I recently read in the news that vermin has been a serious problem in Los Altos after management of an overpopulation of feral cats. It is unlikely, however, that this is the source of all the vermin throughout the area.

Local squirrels are rather puny to stew and are too smart to eat rat poison. Even if I could control them by these methods, my neighbors would certainly not permit it! It is unfortunately a nuisance that many of us will need to contend with until the population equalizes.

Incidentally, gray squirrels are native. Their gray color is better camouflaged against the trunks of native oaks. Red squirrels have been imported—supposedly by a Stanford University professor, formerly from Pennsylvania State University, who thought they were "cute." There are some really sick people out there.

I have no idea where the black squirrels came from, only that they are very aggressive and chase all the other squirrels away. Native gray squirrels are much more common in the Santa Cruz Mountains. Red squirrels are more common in urban areas. The black squirrels are transient in urban areas, relocating within a few months after evicting the red squirrels.

Rats in the garden are not as easily controlled by traps as rats in the home. Placing traps where other visitors to the garden, such as cats and birds, will not find them may present a problem. Poison placed where rats commute can be somewhat effective, but rats may relocate from crowded areas into areas vacated by the deceased. Poisoned rats are attracted to and die near water, including swimming pools. (Ick!)

Wrapping sheet metal (wider than rats can climb over) around the trunks of isolated fruit trees (and adjusted for expansion of the trunk) will obstruct rats' access. Trees that are not isolated may be accessed by limbs of adjacent trees or other structures that extend into the canopy, so sheet metal barriers are not effective in those situations.

Before I conclude, I should correct an editing mistake from the previous gardening column: "Irrigation should be as frequent for rhododendrons as for lawns." Because rhododendrons exhibit shallow and fibrous root systems, irrigations should be somewhat frequent, but the frequency required by lawns is excessive and potentially detrimental to rhododendrons.

Flower of the Week: Orange clock vine

The delicate clock vine, Thunbergia gregorii, climbs or spreads to only six feet but produces boldly vivid orange tubular flowers through summer. It is not nearly as voracious as most vines, but is conducive to many functions. It can be used horizontally as a ground cover or vertically to cover a cyclone fence or cascade over a retaining wall. Full sun exposure, regular irrigation and periodic fertilizer are preferred. The 2-inch-long evergreen foliage is oddly serrate (only a few teeth), with a round tip and lightly coarse hair. Clock vines may be grown from seed. Established 1 gallon vines are often rare in nurseries.

Horticulturist Tony Tomeo can be contacted at 408-358-2574 or at LGHORTICULTURE@aol.com.