Express-News

Saturday, November 22, 2003

By Calvin Finch, Conservation Director, SAWS, and Horticulturist

 

Conifers for South Texas

 

            It was not too many years ago that horticulturists in South Texas recommended the Afghan (Eldarica) Pine as the best choice for a conifer for the area. The tree evolved in alkaline soil, was drought tolerant, and became quickly popular as a landscape tree. A Christmas tree industry also developed. All that ended in the mid 90’s when a fungal dieback called Diplodia ravaged the plantings. Within two or three years the Afghan Christmas tree industry was dead and so were many of the landscape trees.

            The disease was especially deadly for Afghan Pines that were being grown in heavy clay soils. Individual specimens on rocky, sloped land continued to prosper. The net result is that there are still excellent specimens all over the area, especially in the western part of the San Antonio region. Nurseries still sell the trees for landscapes and live Christmas tress, but they are not recommended for widespread landscape planting.

            For folks that want conifers in the landscape, there are a few choices that still can be made. All are good xeriscape plants.

Arizona Cypress is native to a few areas of Texas and seems to be well adapted to our area. It is a dense tree and has the conical shape we like in our conifers. The color is silver-green. Growth rate matches that of an Afghan Pine, 2 or 3 feet per year on most sites. It reaches 30 feet tall and is about half as wide at the base. So far no insects or diseases seem interested in the Arizona cypress. Deer do not eat the needles but many songbirds nest in the foliage. It makes an impenetrable tall hedge.             Arizona cypress is easy to find at area nurseries. Several specimens grow on the Botanical Garden grounds for easy viewing.

Japanese Black Pine is another alternative to the Afghan Pine. It does not reach great heights (25 feet) and is independent in its growth pattern. Some plants look pretty gnarly. It is not a good choice for a uniform evergreen hedge but can be an interesting specimen tree. The growth rate is not as fast as Afghan pine or Arizona cypress but it is moderately fast.

            Italian Stone Pine is nearly as independent in growth habit as Japanese Black Pine. Italian Stone Pine stays relatively short in South Texas (25 to 35 ft). It forms a thick trunk and umbrella-like crown. The tree makes an attractive specimen plant. Growth rate on sites may be less than 1 ft/year. Because of the slow growth rate and independent nature, Italian Stone Pine is relatively expensive at the nursery.

            Montezuma Cypress is a conifer with a difference. It is deciduous. The small feathery needles fall for a short period in the middle of winter. The new foliage is a very showy light green. According to Paul Cox, author of Texas Trees: A Friendly Guide, like Arizona Cypress, Montezuma Cypress is a native to a few scattered locations in West Texas. When it is young, the Montezuma Cypress has a conifer shape but, when it matures, it develops a shade tree crown like the Bald Cypress that are on the Riverwalk or Hill Country rivers. Bald Cypress is a close cousin. It also makes a good landscape tree but does not grow as fast as Montezuma and is less drought-tolerant. Montezuma Cypress growing at the San Antonio Botanical Garden will put 4 to 5 feet of growth on per year (twice as fast as Bald Cypress). The species can tolerate upland soils or soggy soils. For something interesting and different, consider Montezuma Cypress for your landscape.

            Aleppo Pine was extensively planted in past years. It is very tolerant of drought and poor soils. The species grows relatively fast and maintains a classic pine shape with a tall, straight bole and open, narrow branching. If you spend any time at Lackland AFB you see a large number of tall, straight Aleppo pines. Some local specimens, however, are short and gnarly as a result of recurring freeze damage. Mark Peterson, Regional Forester with the Texas Forest Service, says Aleppo pines should be used more often in the San Antonio area. They will be in the market again this year as live Christmas trees. It is a good choice for such a purpose and, after it fulfils its role as a Holiday tree, plant your Aleppo pine in the landscape.