Actually, shattuck trees can only produce shattuck fruit. Lemons grow on lemon trees. I hope this misinformation did not cause much confusion.

Impressive autumn foliar color among the silver maples is nearly as incredible as lemons on shattuck trees. The silver maple is one of my favorite trees but disappoints those expecting it to color as other maples do. However, this year, the foliage that typically becomes dingy gray, brown and pale yellow has been unusually yellow. Although the color still does not compare to that of other species with more remarkable color, it has been drawing attention.

Red oaks have also been coloring better than normal. However, the Pacific maple (bigleaf maple), which has colored more impressively during the previous two autumns, has not done so this autumn. I cannot explain why the various species behave as they do, only that they are much more aware of climatic conditions than I am. Each species reacts uniquely, so each autumn features a different cast of star performers.

The dingy brown among the normally bright yellow tulip trees may have involved more than weather conditions. Many throughout the Santa Clara Valley have been infested with aphid and scale. Both are homopteran insects (of the family Homoptera, which is perhaps more than one needs to know) that disrupt vascular activity among the foliage and emerging stems. This disruption causes premature abscission and defoliation. Necrotic (dead) foliage becomes brown before there has been sufficient time for it to yellow in response to autumn weather.

The sticky substance that falls from infested trees is "honeydew" excreted from the insects. Honeydew is attractive to ants and may become infected with sooty mold. It is particularly bothersome on cars parked below infested trees. Fortunately, honeydew is rinsed away by the recent rain and will not appear while the insects are overwintering. Unfortunately, any grunge that accumulates on cars will need to be washed off.


Plant of the Week: Blueberry

Some of my friends own a historical restaurant in downtown Los Gatos that has blueberry pancakes on the menu. I only tried them once, when a single order for someone else had been prepared twice. I was told that I would like them, but I was not impressed. I still do not know why so many people enjoy the fruit of blueberry, Vaccinium corymbosum. To me, blueberries will always be merely insipid purple lumps in pancakes.

I do, however, enjoy the autumn foliar color, which ranges from bright yellow to bright red. Individual leaves are about 2 inches long, somewhat round and simple. Mature specimens of blueberry are usually less than 6 feet tall, with delicate branch structure. Foliage is therefore not remarkably abundant. Fortunately, not much is necessary to impress those who enjoy autumn color.

Blueberry is related to rhododendrons and azaleas and is native to eastern North America. It consequently prefers slightly acidic soil that drains well. Of course, in the Santa Clara Valley, considerable amendment of endemic soil is necessary to compensate for density and alkalinity. Generous mulch is appreciated for insulation of surface soil to maintain moisture and cool temperatures. Full solar exposure is preferred.

The very small white or pale pink flowers that appear in spring are not remarkable. The green berries that appear after bloom become deep blue through summer and are considered by some to be of ornamental quality.

Two or more cultivars that bloom at approximately the same time will pollinate each other, promoting fruit production. However, too much production will cause the fruit to be of inferior quality and stunt foliar growth. Pruning to remove superfluous fruit may improve the quality of the remaining fruit. Otherwise, simple winter pruning to remove older or less vigorous stems will promote healthier growth among the younger and more vigorous stems.

Additional cultivars that bloom at different times may be used to extend seasonal production of berries if each is in bloom at the same time as at least one of the other cultivars. Those that bloom alone may never require pruning to remove superfluous fruit but may not provide a satisfactory quantity of fruit either.

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