Coyotillo

Karwinskia humboldtiana

Other common name(s):

Humboldt Coyotillo

Family:

Rhamnaceae (Buckthorn Family)

Plant Ecoregion Distribution Map

This map uses data from the US EPA. EPA  servers have been offline frequently so maps may not display. We are working on a solution.

Gulf Coast Prairies and Marshes, Southern Texas Plains
Lower Rio Grande Alluvial Floodplain, Lower Rio Grande Valley, Southern Subhumid Gulf Coastal Prairies
Northern Nueces Alluvial Plains, Rio Grande Floodplain and Terraces, Semiarid Edwards Bajada, Texas-Tamaulipan Thornscrub

Plant Characteristics

Growth Form

Tree

Height

1
to
7
ft.

Spread

1
to
3
ft.

Leaf Retention

Evergreen

Lifespan

Perennial

Habitat and Care Requirements

Soil Type(s)

Sand, Loam, Clay, Caliche, Well Drained, Dry

Light Requirement

Part Shade

Water Requirement

Low

Native Habitat

Grassland

Bloom and Attraction

Bloom Color

Green

Bloom Season

Spring, Summer, Fall

Seasonal Interest

Fruit, Nectar, Larval Host

Wildlife Benefit

Butterflies, Birds

Maintenance

Drought tolerant. Minimal maintenance. Prune only to remove dead branches. Likes to spread into open areas, so give lots of space or thin as needed. Native habitat: prairie, plains, meadows, pastures, savannas. WARNING: poisonous and should not be consumed by humans or livestock. Propagation: semi-hardwood cutting, seed.

Comments

Blooms March-October. Can grow as small tree or tall shrub with soft, lime-green, strongly veined leaves and a nice rounded shrub form. Produces small, greenish yellow flowers. Fruit turns black when ripe. Larval host: Two-barred Flasher butterfly.
Material Treatment Method Collection References
Semi-harwood Cutting Providing a stable environment with the proper humidity and temperature will ensure the cuttings develop roots. Use a well-drained rooting medium and maintain consistent moisture without waterlogging. A rooting hormone may enhance propagation effectiveness. Providing gentle warmth can aid in the stimulation of root development, while ensuring appropriate light levels without direct sunlight is crucial for cuttings to thrive. Select healthy stems in early spring. Care should be taken to cut at the right point, preferably a semi-hardwood section, to facilitate rooting. https://www.picturethisai.com/care/propagate/Karwinskia_humboldtiana.html

About the Region

Fall Symposium 2025 Logo - Teach for the Future

Salado, the location of our Fall 2025 Symposium, lies at the intersection of two ecoregions: the Edwards Plateau (Limestone Cut Plain) and Blackland Prairie (Northern Blackland Prairie).

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 fall Symposium host chapter, the Tonkawa Chapter, includes both of these ecoregions.

Source: Wildflowers of Texas by Michael Eason