Trees can add height and visual interest to any landscape. Planting native trees in a landscape can eliminate the need for watering and prevent the introduction of invasive plant species. Texas has such a diverse landscape and climate range that there are a wide number of native trees to choose from when designing your landscape.
The Osage orange tree, which is sometimes called a may apple tree or a horse apple tree, is now found across the entire United States, but this tree was once found only in narrow river valleys in Texas and southern Oklahoma. The tree spread across the United States in the days before barbed wire because its thick branches and large spikes made it an ideal plant to grow as a barrier hedge to keep livestock in check. The Osage orange tree grows up to 40 feet high with a 20- to 40-foot spread. The tree adapts very well to poor soils, high temperatures and low moisture levels. It produces 6-inch wide, hard green balls as fruit in spring. The fruit is tough and stringy, with a pebbly exterior and a stringy interior.
The wild olive tree is native to the southern tip of the Rio Grand valley. It may be planted as far north as San Antonio, but the tree will die during a hard freeze. The tree produces trumpet-shaped, white flowers with yellow throats that can grow to 3 inches wide in spring. The wild olive produces olive-shaped fruit in drupes (fleshy fruits with thin skin and a hard center stone) once the flowers have fallen off. The fruit is white or pale yellow and turns brown as it matures. Wild olive trees are heat and drought tolerant and will adapt to a wide range of soils. Because of the attractive flowers, the tree is often planted as an ornamental plant through USDA hardiness zone 9.
The plains cottonwood is found in the rolling plains of north central Texas and in the panhandle. The tree is very similar in appearance to the eastern cottonwood, but the plains cottonwood is a smaller and shorter-lived variety. This may be due in part to the harsh climate that it inhabits. The leaves of the plains cottonwood are only serrated half as much as the leaves of eastern cottonwood, and the bud scales of the tree are hairy instead of smooth. The tree blooms in spring. Female varieties produce yellow-green flowers, while male varieties produce purple flowers. Only female trees produce seed, which is released on cotton-like puffs. The tree will tolerate all soil types but requires frequent water. When properly cared for, a plains cottonwood may reach up to 90 feet tall.