Let me tell you the understory
Think of a forest. A deep, dark forest. One where little sunlight penetrates to the ground below.
That’s not the kind of place where you think of planting trees. Yet sometimes you need the look of a tree, especially if all the trees that you do have are towering above your house and its entryway. You want something more on a human scale – a tree (or “trees”) that will grow amidst all those shadows and still survive, even thrive.
As spring arrives over the next several weeks you’re going to notice trees in the woods of the eastern half of the state. They’ll be blooming as your taller trees break bud and leaf out. Those smaller trees are equipped to grow in less than full sunlight. They are the second story trees, more commonly called by foresters, the “understory” trees of the woodland.
We’re not just talking about small trees here. There are small trees that still need full, or nearly full sunlight. That’s where you’d put Texas mountain laurels (if you were growing them tree-form), crape myrtles (same disclaimer), and my heroic little Lacey oak that I love. Those are all trees that mature at 20 to 35 ft., yet they must have half a day of sunlight or more.
Our most common understory trees in Texas…
If you’re looking for a short tree (or shrub that can be trained tree-form) that will tolerate shade most of the day, here are the best.
• Redbuds. We’re now blessed with a dozen or more types, from standard redbuds in pinks, burgundy, and white flowers, and with green, maroon, or variegated leaves. Some have rounded growth to 20 ft. tall and 25 ft. wide, while others are way down to weeping, 10 or 12 ft. tall and 8 or 10 ft. wide. These are well suited to a variety of soils, and they’re winter-hardy all across Texas. The highly variegated types should be protected from afternoon sun.
• Mexican plum. It does well in full sun, but you’ll usually see it at the edges of woodlands. It’s a rugged looking little tree that’s not susceptible to most of the common plum problems. It blooms early with fragrant white flowers that are very popular with honeybees. It, too, handles all kinds of soils.
• Dogwoods. Native to East Texas’ Piney Woods, these require acidic soil. Given that and neutral or acidic irrigation water, dogwoods are lovely spring-flowering trees with dark green summer foliage that turns bright red in fall. Grafted varieties offer red or pink floral bracts.
• Taller hollies. American holly (Ilex opaca) is the queen of the East Texas pine forests. It grows to 25 to 40 ft. tall and 30 ft. wide with age. Some lovely hybrids of American holly are also in the marketplace. Nellie R. Stevens holly is suited to a wider swath of the state (all of it). Yaupon holly is native to the eastern third of Texas, but it’s suited to all the rest of the state. Any of these can be trained single-trunk or multiple-trunk into tree form. All are good in shade or sun. (This Nellie R. Stevens holly above functioned as a large shrub on the Sperry driveway for several decades until I pruned it tree-form. It grows in total shade from overhead pecans.)
• Rusty blackhaw viburnum. This one is a rare find in nurseries, but it’s a gem if you do come across it. Botanically it’s Viburnum rufidulum, and you’ll find it growing natively over the southeastern and south-central United States and into the eastern half of Texas. It’s a large shrub (to 30 ft. tall and 20 ft. wide) that is often turned into a small tree by removal of lower branches. It has clusters of white blooms in the spring, extremely glossy dark green leaves all summer, and small blue-gray fruit that birds covet in the fall. It’s a lovely plant that needs moist soils and shade from mid-morning on during the summer. (At the far corner of our living room, looking out into the woods, I planted this rusty blackhaw many years ago. It is thriving in total shade. I’m in the process of training it tree-form.)