The ants in our neighborhood are easily eradicated from domestic habitation. I have heard otherwise from those who find eviction of these prolific, unsolicited tenants somewhat difficult. Fortunately, insects that live both in the garden and the home are not common. Ants and related termites are able to relocate easily into the home only because they can survive the minimal humidity of home interiors and because they can find sustenance. Very few insects that live in the garden will try to live indoors because sustenance cannot be located.

For example, insects that consume nectar, pollen, other insects or fresh or decaying fruit or foliar material cannot change their diets to consume what can be found in the home. Even if sustenance was available, most insects associated with the garden would become desiccated by the dry air of home interiors.

Likewise, household pests that consume household material and prefer minimal humidity cannot prosper in the garden. Even cockroaches, which are omnivorous and can be temporarily sustained by decaying fruit in a garden, prefer to live in kitchens, where sustenance and moisture are readily available, but the air is dry and warm. I considered explaining this to my neighbor who will soon pave over the garden in an attempt to control household pests, but came to the conclusion that perhaps the ants might be enticed to relocate from my garden to the expansion joints of the new pavement next year.

Although garden pests are not nearly as active now as they are during warm weather, "dormant" sprays may be applied to dormant, deciduous plant species to control overwintering insects and spider mites as well as fungal diseases. (Spider mites are arachnids related to spiders, not insects.)

Fungicides are not only more easily and more effectively applied to dormant trees but also will not damage foliage if it is not present. However, evergreen species may be damaged by overspray of phytotoxic chemicals that are otherwise harmless to dormant stems. Horticultural oil, such as Volk oil, is as harmless as vegetable oil, but effectively coats and suffocates eggs left by insects and spider mites. Oils are not likely to cause foliar phytotoxic symptoms but should be applied to dormant stems simply because there is no need to waste the oil on foliage that will soon be abscised.


Tree of the Week: Douglas fir

The Latin name of Douglas fir, Pseudotsuga menziesii, translates into "Menzies' false hemlock." It is neither a fir (Abies) nor a hemlock (Tsuga), nor is it named after Douglas. It is not common in refined gardens but is prominent throughout the Santa Cruz Mountains and is perhaps the most popular cut Christmas tree. It is the most common species in the forests of the Northwest and has been the most common lumber used to build homes throughout the Santa Clara Valley after the Victorian period.

Unpopularity is a result of the disproportionate height of mature specimens and because the height cannot be limited without severely compromising structural integrity. Mature trees in forests may be taller than 200 feet but are much shorter in the Santa Clara Valley because minimal humidity stunts foliar growth and because there is no need to compete with comparably tall trees. Dense soil on the floor of the valley can be tolerated if irrigation is not too generous.

The deep green needles are approximately 1 inch long. Foliage is dense if very exposed but may be sparse if shaded. Burgundy-colored buds that appear at stem tips in winter become pale green "tassels" of new growth in spring. Reddish cones approximately 3 inches long hang downward rather than remain suspended upward like those of firs. The distinctive bracts with three lobes that protrude from below the cones' scales resemble the hind legs and tail of a mouse that has been flattened on the road. (I didn't make that up; I remember one of my college professors saying it.)

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