By Bill Ward
Published in The Boerne Star on December 10, 2002
My brother called me a hypocrite for publicly touting native plants while privately keeping a greenhouse full of exotic plants. But he missed the point.
Neither I nor any other member of the Native Plant Society of Texas (NPSOT) is opposed to raising exotic plants per se. All of us have non-native plants in our yards. Most of us, however, are increasingly careful which non-native plants we use in landscaping.
This caution grew from two concerns:
1) Many exotic plants guzzle a lot more water than native plants and
2) Several introduced plants are known to easily escape into the wild and drastically change the local ecology.
Water is undoubtedly the Hill Country’s most precious natural resource. For this reason, one important goal of our Boerne Chapter of NPSOT is to promote landscaping with plants which require little water.
Local native plants, once established in a yard or garden, generally can be maintained without frequent watering. In addition, any native plant that escapes cultivation is not likely to disrupt the native ecosystem. Some exotic plants require little water and do not become invasive pests. A shrubby example of this kind of exotic is rosemary, native to the Mediterranean. I think rosemary makes a good companion for many of our cultivated native plants, in both formal and informal gardens.
Good choices for non-invasive, drought-tolerant bloomers are the various Salvias native to northern Mexico. There is a Mexican Salvia for every season from spring through fall. Who could object to using these kinds of non-natives in landscaping? Unfortunately, some escaped exotic plants are so tolerant of our local climate and calcareous soil that they have become major threats to native habitats.
Noteworthy among these in the Boerne area are Chinese tallow and ligustrum, both native to the Orient and both widely used as landscape plants in Boerne. These invasive exotics are found growing in abundance along Cibolo Creek downstream from Boerne.
There is growing concern that the ecological diversity of the riparian habitat at the Cibolo Nature Center is in danger of being lost to thickets of Chinese tallow and ligustrum, not to mention the massive growths of Japanese honeysuckle and periwinkle.
The invasion of exotic species here could substantially change the ecology of one of the only areas of public access to Cibolo Creek in its natural setting.
For this reason, there will be an organized effort to remove invasive exotic vegetation along Cibolo Creek at the Cibolo Nature Center. This will be a long-term project that will require a lot of volunteers.
First, we will concentrate on the Chinese tallow, using techniques recommended by the Texas Forest Service and the Nature Conservancy.
It is not enough to cut down the trees, because they readily resprout from the stump. An effective method is to paint the stump with herbicide immediately after cutting.
If the herbicide is applied before the cells of the cortex contract, it is sucked into the system and will kill the plant.
Herbicides used in a riparian area need to be rapidly decaying and leave no residue in the soil and should be contained in an emulsion that is nontoxic to aquatic life.
The treated stumps will be marked and mapped with GPS so that they may be monitored for resprouting.
This program for eradication of invasive exotics along Cibolo Creek wiil begin with a session from 9 a.m. to noon Saturday, Dec. 14, with workdays every month through March.
Everyone is invited to participate in this battle to control the alien invasion, which left unchecked will destroy the native riparian habitat along a beautiful stretch of Cibolo Creek.
To sign up, please call the Cibolo Nature Center at (830) 249-4616.
