If you are interested in garden design, one important concept to familiarize yourself with is layering. Including plants of several different heights in your garden results in not only a more beautiful display, but also a healthier ecosystem for your valuable plants to thrive. A good garden design should include vegetation in each of these categories: canopy trees, understory trees, shrubs, forbs and grasses, groundcover, and vines. This article discusses the shrub layer, which consists of long-lived plants that are typically 5 to 12 feet tall. To help you nativize your Houston-area garden, I suggest a few of my favorite showy shrubs to include in your landscape.
American Beautyberry
Callicarpa americana
Everyone can find something to enjoy about the American Beautyberry, but especially the bird people. The show starts in May with small but profuse, delicate pink flowers, like an army of tiny ballerinas. In October, these flowers become brilliant purple fruits, covering the entire bush. Birds love these berries, which are technically edible but not very palatable for humans. Beautyberry likes part shade and will grow 3 to 9 feet tall, depending on the conditions. A specimen plant may grow taller, whereas a group will stay compact. This unfussy shrub does not like fertilization or rich soil, so just stick it in our native soil and keep it watered until establishment. As with any native, be sure to get the right species, as a Japanese Beautyberry is also sold in nurseries.
False Indigo Bush
Amorpha fruticosa
The flowers of this bush are quite striking purple spikes with orange stamens. The blooms appear in early April and last until June or July. One great reason every garden should have this species: as a legume, it attracts beneficial nitrogen-fixing bacteria. Additionally, this bush acts as a larval host for a number of butterfly species, including the Silver-spotted Skipper, Southern Dogface, California Dogface, Gray Hairstreak, and Hoary Edge. This deciduous shrub grows to about 12 feet in sun or part shade.
Coralberry
Symphoricarpos orbiculatus
This member of the honeysuckle family grows low and tolerates shade. Given a typical, mild Houston winter, the plant stays green all year. On the short side, it is unlikely to exceed 6 feet. The greenish white, inconspicuous blossoms of this shrub appear in late April, followed by the bright pink fruits, the plant’s namesake. It may be difficult to find this plant in nurseries, but it is easy to propagate through runners, which it puts out profusely. Anyone who grows coralberry likely will observe its runners migrating to their preferred post in the garden.
Virginia Sweetspire
Itea virginica
Virginia Sweetspire is the shrub visited by the most pollinator species in my garden. In early spring, fragrant white, four-inch spires cover the shrub, making it a magnet for bees and butterflies. Multiple blooms are likely through June, and the leaves turn burgundy in the fall, giving your garden’s visitors another delightful show. In Houston, this plant will only go dormant in harsh winters. It can tolerate poor drainage and is commercially available. It prefers part shade or part sun. Grow this plant as a specimen or in a row as a hedge.
Evergreens – Cherry Laurel, Wax Myrtle, Yaupon Holly
Your shrub layer should include plants that stay bushy all year. Strong, sturdy shrubs won’t necessarily be the ones that give you showy blooms. To withstand Houston’s freezes, droughts, floods, and hurricanes, make sure you include at least one species of hardy evergreen in your shrub layer. Most people expect to see boxwoods or ligustrum in a typical Houston landscape installation. However, these species are not native, and ligustrum, also known as privet, is actually highly invasive and produces allergenic pollen. To avoid these undesirable effects, make native plant selections to benefit both wildlife and your wallet (by avoiding costly replacements).
Cherry Laurel (Prunus caroliniana), Wax Myrtle (Morella cerifera), and Yaupon Holly (Ilex vomitoria) are excellent native selections that you can keep as an evergreen foundation hedge. Dwarf and full-size varieties are available at most nurseries; however, note that dwarf varieties, like all horticultural varieties, are not technically native species, as the DNAs have been altered by the nursery trade. The native varieties grow to be 15 feet or taller if left to their own devices, but all three are slow growing and allow themselves to be pruned and trained into existing as much shorter shrubs. I encourage my readers to experiment with shrubbing and espaliering these small trees.
Honorable mentions – Gregg’s Salvia, Esperanza, and TX Barometer Bush
Recognizing that some gardeners may want more options that will compete with the shows put on by knockout roses, hydrangeas, azaleas, and the like, we may need to reach beyond the highly localized standard of native. While “Texas native” may be too broad of a term to do us much good, we may look to our neighboring ecotones in Central and South Texas for more shrub varieties with showy, long-season curb appeal. I would be remiss not to recommend some great, drought-tolerant nearby natives – Gregg’s Salvia (Salvia greggii), Esperanza (Tecoma stans), and TX Barometer Bush (Leucophyllum frutescens). These central Texas natives are better adapted to the dry, sunny conditions on roadsides and parkways while still offering benefit to native pollinators. I don’t include these species in every design, but I offer them as options when people are looking for more color.
When the Show’s Over
If and when your shrub goes dormant, be sure to leave the dead branches attached until you see a basal rosette the following season. This way, you will not forget the shrub is there, underneath the surface of the soil, while protecting the new growth. If you need to prune the shrub for clearance, avoid removing more than 33 percent of the foliage at once. Natives do not need fertilizer or supplemental water after establishment if they are in the appropriate conditions. So sit back, relax, and enjoy the ride, because you are in for a treat if you plant these showstopping shrubs in your garden.
