It has also been gratifying to be occasionally reminded that although this column is available only to the limited local audience, many seem to enjoy reading it almost as much as I enjoy writing it. I am amazed at how many come to Scotts Valley to attend the Open House events at Bay Laurel Nursery and want to discuss their gardening issues with me directly. I have consequently been wanting to be more available to the public locally.

The City of San Jose, the San Jose Public Library and Friends of the Willow Glen Library have recently made that possible by arranging for me to give a brief lecture free to the community. The main topics to be discussed include selection of nursery stock and basic pruning techniques, but questions are encouraged throughout the lecture and there should be time afterward for questions concerning other topics. The lecture will be at the Willow Glen Library, 1157 Minnesota Ave. in San Jose on Oct. 8 at 7 p.m. More information can be obtained by calling the library at 408.998.2022.

Sudden Oak Death, or SOD, has been a serious horticultural concern locally for several years as it has annihilated many groves of native coast live oak trees throughout the San Francisco Bay Area. Much of the information recently presented by the media has unfortunately caused considerable unfounded confusion. Many more species have been found to be susceptible to infestation of the fungus (Phytophthora ramorum) that causes the disease, but few express symptoms resembling those exhibited by infested coast live oaks.

Specimens of susceptible species that are infected may transmit the disease to coast live oak trees, but are unable to transmit it without prior infection. This may seem ridiculously obvious, but it has been a concern among those who believe that any susceptible species threatens the oaks.

The fungus seems to sporulate (produce viable spores) less profusely while infesting certain hosts, so that transmission of the disease is considerably less likely than it would be from "preferred" hosts. The only host that has been observed to promote severely profuse sporulation of the fungus is the native bay laurel trees. In native forests, many of the most severe infestations among coast live oak have been observed within close proximity of infested bay laurels.

Although coast redwood trees have been positively inoculated with the fungus and may possibly become infected with it, natural susceptibility has not been observed and is presently unknown. If redwood trees can be naturally infected, those near infected bay laurel trees are considerably more likely to be affected than those isolated from other hosts. Such probability is relevant to infestation of any host. For example, the West Nile Virus is a serious disease, but has not yet been observed locally. I am therefore not yet worried about getting it.


Perennial of the Week: Tree aloe

The tall, branched clusters of yellow, orange or rosy red flowers of tree aloe, Aloe arborescens, do not appear until winter, but the long blue-green leaves are appealing throughout the year. Foliage is thick and fleshy with soft teeth at the edges and lighter green spots throughout. Young specimens begin as single rosettes, but begin to branch as the primary rosette matures and forms a basal stem. Small basal shoots (side-shoots) may be removed and rooted or left to develop into branches.

Mature specimens may be higher than 10 feet. Tree aloe prefers well-drained soil and good solar exposure, but tolerates minor shade. Almost all aloes tolerate drought, but may be damaged by frost. Most are also very adaptable to and striking when displayed in containers.

Tree aloes are often acquired as medicinal aloe, Aloe vera, but grow much larger than expected. Medicinal aloe is actually more delicate, with multiple shoots of vertical foliage emerging from horizontal stems.

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