Austin Invasives

by Mary Allaway

Invasive species can be seen growing all over Austin, in our parks, green belts and neighborhoods. According to a USDA report, Executive Order 13112, section 1 defines a species as invasive if it is 1) non-native to the ecosystem under consideration and 2) whose introduction causes or is likely to cause economic or environmental harm or harm to human health (www.invasivespeciesinfo.gov). Invasives cost the U.S. as much as $137 billion annually, and invasive animal species, such as feral hogs and zebra mussels, are also part of the cost (www.texasinvasives.org/i101).

Some of the common invasives in the Austin area include Chinaberry, domestic nandina, ligustrum, red tip photinia, pyracantha, Johnson grass, golden running bamboo, and Bermuda grass (unless it’s a hybrid with no seeds). Fellow gardeners have made me aware of many of the commonly seen invasive plants in the Austin area but many other local gardeners are uninformed of the problem. An extensive list of invasive plants in Central Texas is available on the City of Austin website with pictures, spreading and removal information (www.austintexas.gov/invasive). Despite being on the invasive list, there are no legal ramifications to planting or selling invasives, and they are often sold locally.

Although many of my fellow gardeners are aware of the most commonly seen invasive plants in the Austin area, many other local gardeners are uninformed of the problem.

Planted 18 years ago, the collection of mostly native species growing along the street in front of my house includes Texas redbud, Texas mountain laurel, Texas sage and Mexican plum and they look like they have been there forever. One of my neighbors admired it so much that he decided to plant a “native” garden, as well. I suggested he ask for native plants at the nursery, but several weeks later, a row of ligustrum showed up in his garden! The house was eventually sold and the new owner pulled out the ligustrum and planted bamboo; at least it is the non-running kind.

Golden Running Bamboo
The lot on the other side of my house has had golden running bamboo on the far side for probably about 60 years. It is now encroaching on our lot.
The “bamboo removal man” who came to look at it said, “It’s good to eat; it tastes like cabbage.” I don’t think so. According to Texas A&M AgriLife Exension, the main removal method, other than digging it out by the roots, is to starve the plant by cutting down the stalks persistently. The food in the underground rhizomes will eventually be exhausted, and the plant eventually dies (https://aggiehorticulture.tamu.edu/archives/parsons/trees/bamboo.html). The extension phone desk periodically receives calls about this invasive.

Typically the bamboo has come from the lot next door and the caller wants to know if the city or county will help with removal. I am not aware of any available government assistance, but there are local landscapers who can help dig out or cut back excessive growth.

Cedar
Even though cedar is a common complaint, due to its prevalence and the allergic reaction it provokes, cedar is not designated as an invasive species. Cedar has lived in Texas since before the first European immigrants settled here. Many birds depend on cedar berries as a staple in their diet. Cedar is a xeriscape plant that retains and uses its water very efficiently, but they are large trees that take a lot of water, which results in less water being available for other plants, streams and underground aquifers. Three species grow naturally in Central Texas: ashe juniper (Juniperus ashei), eastern red cedar (Juniperus virginiana), and red-berry juniper (Juniperus pinchotii) (http://texasconservation.org/resources/ReadYourLand.pdf).

The Grow Green guide, Native and Adapted Landscape Plants, developed by the City of Austin and Texas A&M Agrilife Extension, is a great resource. Gardeners seem to love it. Inside you will also find a list of Austin’s top invasive plants to avoid. The guide can be downloaded or read online at https://www.austintexas.gov/watershed_protection/publications/document.cfm?id=198301. There is also an online, searchable database at https://austintexas.gov/department/grow-green/plant-guide. Word is getting out, but further education concerning invasive species is needed to help curb an already existing problem.