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Express-News Weekly Column Saturday, December 2, 2000 Submitted by Calvin Finch, Ph.D., Director of Conservation, SAWS, and Horticulturist

CONIFERS

Everyone loves conifers. Conifers are trees that have needles such as cedars, pines and cypress. They are usually evergreen and have a conical shape (classic Christmas tree shape).

The infamous cedar is a conifer and an important part of many landscapes. Most of us would not think of planting one on purpose, but they are good wildlife plants and contribute to the “hill country look.” If you have cedars in your landscape and want to maintain them, the key factor is to avoid over-watering. If you have a St. Augustine lawn and are watering it enough to keep it green, you can expect your cedars (and mesquites as well!) to decline and die within a few years.

Another native conifer, the bald cypress, prospers in moist locations. It is the tree that dominates the San Antonio Riverwalk and many hill country rivers. Bald cypress can reach 60 or 70 feet tall with a 35 or 40 foot crown on good sites. It is unusual for its tolerance of wet sites and for its deciduous habit. In late fall the bald cypress turn rust colored and then drop their needles. In early spring they put on showy light-green needles that eventually darken. Despite its preference for moist soils, bald cypress is on most xeriscape lists. It may drop its needles early during severe droughts but has a fast growth rate as a lawn tree on dry sites. The related Montezuma cypress is even a better choice for the landscape. It is more drought resistant than bald cypress, forms a wider crown, is almost evergreen, and grows even faster. On some sites it may add seven or eight feet of growth per year.

Until seven or eight years ago the Afghan pine (Pinus eldarica) was the recommended choice for an evergreen species in the San Antonio area. That was before the fungus disease diplodia wiped out large numbers of our landscape trees and the central Texas Afghan Christmas tree plantations. In heavy, poorly drained soils the disease kills the branches from the bottom up within a year after the infection shows up. Although pine tip moths do not kill the trees, they are also a problem. They bore into the growing points of branches from the top down. I kept the moths at bay in my trees with an orthene spray every two weeks from February through May. If you have well drained soil and want to take a chance on Afghan pine limit the gamble to one or two trees.

Japanese black pines are used effectively as a specimen tree in San Antonio landscapes. They do not always have a classical conifer shape. Japanese black pines have a twisty, open growth habit and, depending on the site, can grow rather slowly.

Arizona cypress may be the best overall choice for a conifer for San Antonio landscapes. It is native to West Texas and New Mexico. In San Antonio it grows quickly (3 to 4 feet per year) and does not seem to be bothered by diseases or insects. It has a conical shape but with a wider base than the Afghan pine or bald cypress. The silver-green color can be an asset or detraction depending on your preference. Plant Arizona cypress as a specimen tree in a xeriscape or as a tall (30 ft), wide hedge.