Not all aggressive plants are bad, and not all pretty ones are good. In East Texas, the spread of invasive exotic plants, which are non-native species that escape cultivation and overrun natural areas, is one of the most pressing threats to our local ecosystems. These invaders displace native plants, disrupt ecological balance, and reduce food sources for native wildlife.
It is important to understand the difference between native plants, naturalized non-natives, and true invasives. Vigorous natives like yaupon holly or trumpet creeper may spread, but they are part of our ecosystem and support native birds and insects. Some exotic plants, like crapemyrtles or jonquils, may persist or even naturalize outside of cultivation but do not overtake natural ecosystems.
In contrast, invasive exotic plants aggressively colonize wild areas, outcompeting natives and damaging habitat. Chinese privet, Chinese tallow, Japanese honeysuckle, Japanese climbing fern, water hyacinth, and giant salvinia are among the worst offenders in East Texas.
Dr. Doug Tallamy, professor of entomology and wildlife ecology at the University of Delaware, has led research showing how invasive plants impact wildlife. His studies reveal that native plants support 35 times more caterpillar biomass than non-native species. This is critical because 96 percent of North American birds rely on insects, especially caterpillars, to feed their young. Fewer native plants means fewer insects, which results in fewer birds.
Tallamy’s research also shows that suburban yards dominated by exotic ornamentals function like food deserts for native insects. Invasive species like Japanese honeysuckle or Chinese privet replace the native plants that insects have evolved with over thousands of years. These host-specific relationships are essential for survival, and when lost, insect populations collapse. This affects birds, bees, butterflies, and other animals that rely on them.
Chinese privet, once popular as a hedge, now forms dense thickets in our forests, crowding out wildflowers and tree seedlings. Chinese tallow, an ornamental tree with colorful fall leaves, invades pastures and wetlands. Japanese honeysuckle smothers shrubs, native honeysuckle, and entire fencerows. Aquatic invasives like water hyacinth and giant salvinia clog up lakes and streams, block sunlight, reduce oxygen, and threaten fish and water quality.
These invaders do more than threaten biodiversity. They change the very character of our landscape. Open meadows become monocultures. Forest floors lose their flowers. Lakes become unrecognizable. Gardeners and landowners can help by removing or killing known invasive species on their properties and choosing locally native plants instead. There are appropriate, environmentally friendly options that provide food and shelter for birds and pollinators.
Dr. Tallamy encourages everyone to join his “Homegrown National Park” movement by turning part of their yard into native habitat. You can learn more at homegrownnationalpark.org. You might also consider joining our local chapter of the Native Plant Society of Texas (npsot.org). I’m a lifetime member!
