Once again Texans celebrated Arbor Day, on Friday, Nov. 3. Last year this column addressed some of my favorite trees for East Texas; this year I’d like to write about trees that no East Texan should plant.
When you plant a tree, you’re not planting for yourself - you’re planting for your children and grandchildren. So when you choose a tree, you should consider the lifespan of the tree. Some trees that are commercially available are very short-lived - you can usually tell because the description on the tag will say ‘fast growing’ or ‘instant shade.’ Trees such as silver maples, fruitless mulberries, ornamental pears, and willows may last no more than 10 to 25 years, and may have problems during much of that time. For long-lasting trees in East Texas, look to oaks, pecans, and other natives like blackgum. Magnolias and male gingkoes grow a bit more slowly but are marvelous trees for the landscape.
In addition to these short-lived trees, there are also trees that are subject to frost or wind damage, insect problems and disease. These include hackberry, Siberian elm, Italian cypress, green ash and sycamore trees. Other trees are messy, like cottonwood, catalpa, fruiting mulberry and female gingkoes. Honey locust trees have those brutal thorns and are best not planted in a landscape. Some of these trees are useful in a wildlife garden, but don’t expect them to be a long-term part of the landscape.
The final group of trees that should not be planted is those that are invasive species. While not native to East Texas, these trees are extremely well-adapted to our climate and soils. (Please note that not all non-native trees are invasive.) Since they’re foreign to this region, they lack the natural competitors, predators, and diseases that would keep them in balance, so they spread unchecked and form a monoculture. However, our woodlands and pastures are home to many animals including birds and insects, which depend upon native trees for sustenance.
There are several trees that are invasive in East Texas: Chinese tallow tree, chinaberry tree, mimosa and empress tree. All outcompete native plants, are difficult to eradicate once established (most will resprout when cut), and are destructive to our environment.
Chinese tallow tree can grow to 60 feet, with oval leaves and dangling yellow flowers in spring; the white seed pods in the fall are also ornamental. Chinese tallow was brought to the Gulf Coast in the 1900s by the USDA to establish a soap-making industry. Its leaves contain a toxin that creates a soil environment where other plants cannot grow, and its long taproot ensures it success. Both the leaves and fruit are toxic. Chinese tallow is common in roadside ditches.
Chinaberry tree is a fast-growing tree with lacy dark green leaves, brought to the U.S. as an ornamental tree. I have to confess that it is one of my favorite flowering trees - the lavender blooms in spring are as fragrant as lilacs. The toxic seeds persist on the tree in the fall after the leaves have fallen. Chinaberry is resistant to insects and diseases, so it outperforms other trees. Its fallen leaves increase the alkalinity of the soil, so that native seeds cannot sprout or thrive. You will find chinaberry along roadsides and around old homesteads.
Mimosa is a familiar sight along East Texas roads, with its ferny leaves and showy pink puffball flowers that are fragrant and attract hummingbirds. It was also introduced as an ornamental tree. Mimosa is tolerant of many environments, and forms dense stands that crowd out native plants. Mimosa seeds are remarkable for maintaining viability for as much as 50 years. If growing along a creek or river, the seeds can be dispersed downstream along the banks.
The empress or princess tree is one of the fastest-growing ornamental trees in East Texas, with root sprouts growing 15’ a year. It has showy purple flowers in the spring, followed by large fuzzy heart-shaped leaves. The empress tree was introduced in the 1800s when its seed pods were used as packing material from China. It rapidly grows in disturbed area, and each tree produces millions of seeds that are spread by wind.
From these descriptions, you may be tempted to plant an invasive tree in your yard. As stewards of our land, we have to see past their beauty to their potential destruction of native Texas. Can you imagine no birds or butterflies in your East Texas garden?