One day the land just back of the soon-to-be-built Boerne Public Library will be a pleasant wooded slope with pathways winding through native trees and shrubs down to shady banks of an intermittent creek. It will be a place to take a stroll, read a book, watch birds and butterflies, study native plants… a place to enjoy Nature.
Currently, however, it is one of the most devastated and ugly landscapes in Boerne. This is not a woods where you’d enjoy a morning walk.
The main culprits in the decline of that tract of land are waxleaf ligustrum and a herd of axis deer that camps out in the ligustrum forest. The ligustrum trees are so thickly grown together that little sunshine reaches the ground, and what few forbs and bushes can survive in the dim light are browsed away by the deer.
Without grass and other groundcover, runoff is high. What soil has not been eroded away is thin and dry. The narrow, usually dry stream bed at the base of the slope has no sign of riparian vegetation. That rocky creek bed may as well be one of those cement canals so common in the creeks of that big city on our south. It is a conduit for sending flash floods downstream at maximum velocity.
Paul Barwick, Senior Planner for the City of Boerne, has detailed plans for transforming the future Boerne Library grounds into an inviting campus with native-plant gardens, natural woods with native understory, and lush riparian banks soaking up creek water and slowing erosion during floods. The first step in this ecological restoration is removing the ligustrum.
What’s so bad about ligustrum? Waxleaf ligustrum or Japanese privet (Ligustrum japonicum) has a lot of qualities we like in landscape plants. It is evergreen, very drought tolerant, doesn’t require fertilizers, and grows rapidly. Those traits have made it a popular landscape shrub or small tree for a long time. It used to be one of the favorite shrubs for urban yards in Texas and the South. Some people say it still is overused.
Unfortunately ligustrum has a major flaw. It is not compatible with our native vegetation. It is prone to escaping into the wild and dramatically changing native habitats. Ligustrum invades and plunders as it goes. It replaces native vegetation, thereby changing the whole ecosystem it invades.
Most lists of undesirable invasive exotic plants of Texas include at two species of ligustrum. Although this invasive plant produces abundant fruit, the USDA ranks its food value to mammals and birds as low. Birds that do eat the berries seem to have a major role in spreading the plant. From time to time I have to pull ligustrum seedlings out of our flower beds, even though I know of no ligustrums in our subdivision.
The Boerne Chapter of the Native Plant Society has pledged to lend a hand in de-forestation of the ligustrum woods at the new library site. Many of us already are practiced at removing ligustrum, because it is one of the main exotic plants invading and damaging the riparian corridor at the Cibolo Nature Center.
So far, the Boerne Chapter has participated in two work sessions at the library property. Even with three chain saws going for three hours at the last work day, much more ligustrum is left to cut. This is a huge thicket with all trees tall and skinny, reaching for the sunlight. The ligustrum is so closely intergrown that a tree won’t fall over when cut off near the base; it is held erect by limbs of adjacent trees.
No permanent damage is done to ligustrum trees by just cutting them down. They readily re-sprout. To be sure they are gone forever, stumps need to be sprayed or painted with a systemic herbicide immediately after cutting. When construction starts on the new library, the cuttings will be mulched and spread by the site contractor to further reduce erosion. The ligustrum roots are being left in place to reduce further loss of the little soil left.
Some day before long, the Boerne Public Library campus will be the pride of Boerne.
By Bill Ward
Published in The Boerne Star in November 2009
