Boerne Chapter

Black dalea – NICE! for hot, dry gardens

Our prolonged drought and brutal heat wave have just about worn down my enthusiasm for writing about native plants in the garden. Even long-established native plants are suffering, while it is getting more and more necessary to forgo irrigation throughout much of the Hill Country, because most of the aquifers are providing less and less water.

Mound of purple flowers
Mound of black dalea in bloom. (photo by Jan Wrede)

Luckily for me, the plant-of-the-month committee of Operation NICE! (Natives Instead of the Common Exotics!) has picked a local native that I can feel good about, even now. The September plant of the month is black dalea (Dalea frutescens), a highly drought-resistant little shrub with small purple and white flowers. It is one of the plants still green in our backyard.

Black dalea is a low airy shrub, commonly forming mounds a few feet wide and a couple of feet high. Its small leaves are pinnately compound, usually with 13-17 tiny leaflets on each leaf. The bloom period is from mid summer to mid fall. Last year ours was in full bloom during September. Clusters of purple and white flowers are born on short stalks toward the ends of the branches. Individual flowers are only about half an inch long, but the blooms may be dense. In full flower, the black dalea is an eye-catcher.

Some small clumps of black dalea were planted by a good friend of mine who loves native plants, but doesn’t particularly enjoy gardening. She stuck the daleas on a rocky slope behind her house and didn’t give them much more attention. I would guess they never were watered after they were first planted. Now those little clumps have grown into large mounds that are spectacular during the blooming season. This plant of the month is pretty tough.

Black dalea seems to do just fine in open sun and in well-drained calcareous soil without a lot of watering and fertilization. The Boerne Chapter of the Native Plant Society of Texas provides free planting and care instructions for black dalea at nurseries participating in Operation NICE! (Hill Country African Violets & Nursery and Maldonado Landscape & Nursery) and at Cibolo Nature Center. Probably it wouldn’t be advisable to put any new plants in the ground before late September or October or whenever this heat lets up.

Close up of a plant with lots of small purple flowers
Black dalea in bloom last September. (photo by Bill Ward)

In Texas there are at least 39 species of Dalea, most of which grow in dry parts of the state. The black dalea grows from southeastern Oklahoma through central North Texas, around the eastern and southern parts of the Edwards Plateau, through the Trans-Pecos, and across northeastern Mexico.

Kendall County is one of the places it has been collected by botanists, but so far I haven’t been able to find it in the wild. Chuck Janzow saw black dalea on the I-10 right-of-way in Boerne some years past, and Jan Wrede and Kim Kuebel spotted it on Highway 46 in western Kendall County many years ago. It is not common around here.

Jan Wrede writes that black dalea has been removed from much of its former range by cattle browsing (“Trees, Shrubs, and Vines of the Texas Hill Country”). The severe overpopulation of deer probably will lead to its elimination in many areas of the Hill Country. Reportedly, black dalea survives where it grows within the protection of sticky agarita branches in parts of Kerr County. If you find black dalea in the wild, it is worth protecting.

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About the Region

New Braunfels, the location of our Fall 2024 Symposium, straddles both the Edwards Plateau Ecoregion and the Blackland Prairie ecoregion. Interstate 35 divides the city of New Braunfels; its path through the city closely parallels the boundary of these two ecoregions, with the Edwards Plateau on the west side and the Blackland Prairies region to the east. The Edwards Plateau area is also called the Hill Country; however, this general term covers a much larger area extending farther north. Spring-fed creeks are found throughout the region; deep limestone canyons, rivers, and lakes (reservoirs) are common. Ashe juniper is perhaps the most common woody species found throughout the region. Additional woody species include various species of oak, with live oak (Quercus fusiformis) being the most common. Sycamores (Platanus occidentalis) and bald cypress (Taxodium distichum) border waterways. This area is well known for its spring wildflower displays, though they may be viewed in spring, late summer, and fall, as well. According to Texas Parks and Wildlife, average annual rainfall in the Edwards Plateau ranges from 15 to 34 inches.

The Blackland Prairie extends from the Red River south to San Antonio, bordered on the west by the Edwards Plateau and the Cross Timbers, and on the east by the Post Oak Savannah. Annual rainfall averages 30 to 40 inches, with higher averages to the east. This region is dominated by prairie species. The most common grass species include little bluestem (Schizachyrium scoparium) and Indian grass (Sorghastrum nutans) in the uplands and switchgrass (Panicum virgatum) in the riparian areas and drainages. Common herbaceous flowering plants include salvias, penstemons, and silphiums. This area has suffered greatly from overgrazing and agricultural use. Few intact areas remain, though many of the plants can be found along county roadsides throughout the region.

Our four host chapters (New Braunfels, Lindheimer, Guadalupe, and the Hill Country chapters) are located in one or both of the ecoregions above. However, the eastern portion of Guadalupe County also falls within the Post Oak Savanna ecoregion. Annual rainfall averages 35 to 45 inches, with higher averages to the east. A wide variety of hardwood trees are found, including several species of oaks, elms, and in the Bastrop area, loblolly pine (Pinus taeda). Grasses and forbs dominate in the open savannas, with most common grass being little bluestem. Ranching, agriculture, and fire suppression have allowed woody species to encroach on the once-open savannas.

Source: Wildflowers of Texas by Michael Eason