Coralbean

Erythrina herbacea L.

By: Samantha Fisher

Introduction

Erythrina herbacea L. is an enticing plant, with its unique flowers and its bright red seeds. Do not let this plant’s beauty fool you, as it is extremely toxic if ingested in concentrated amounts. Make sure to keep it away from children or pets who may ingest it!

Erythrina herbacea L., often referred to as coralbean, is an herbaceous shrub that can range in size from 5-12 feet; however, they can be found smaller than 5 feet. It is an evergreen plant; therefore, its leaves do not change color in the fall. The leaves can be 4-9 inches long, with leaflets as large as 3 inches. Coralbean is best known for its beautiful red flowers that are produced between late winter and early spring. These flowers are tubular in shape and can be up to 2 inches long. The fruit of the coralbean is stored in a brown pod. Once the pod dries out, it turns black and bursts open, exposing bright red seeds. The plant is protected by small thorns on its trunk and branches (Gilman et al., 2019).

Taxonomy

Erythrina herbacea L. has a variety of common names, including coralbean, Cherokee bean, and red cardinal (Lady Bird Johnson Wildflower Center, 2008). Coralbeans are vascular plants, meaning that they use xylem and phloem to transport resources, such as water and photosynthate, throughout the plant. Coralbeans produce tubular flowers and are classified as dicots. The coralbean is found in the family Facaceae, or the pea family, due to its pea pod. When the pods mature, they turn into a dark, black color and open to reveal the plant’s bright red seeds (University of Florida, n.d. B). The taxonomic classification below is provided by the United States Department of Agriculture (n.d.).

Niche and Habitat

The coralbean attracts butterflies and hummingbirds due to the nectar it produces. Additionally, this plant is popular among small wildlife, such as birds, that consume the coralbean seeds once the pods break open and expose them. The consumption of seeds by wildlife primarily occurs from late summer into the fall (University of Florida, n.d. A). Consumption of seeds occurs despite the plant’s toxicity.

The coralbean is a native plant found in the southeastern United States, Texas, and the Gulf of Mexico. It is found within coastal plain landscapes and thrives in drier, sandy soils that are slightly acidic and well-drained. Coralbean plants are drought-tolerant. Light requirements include sun with partial shade. Coralbean can tolerate moderate amounts of salt in the soil and high amounts of salt in the air, allowing it to thrive in coastal environments (University of Florida, n.d B). It is cold tolerant; however, it can be damaged by frost (Lady Bird Johnson Wildflower Center, 2008).

This plant is rare along the coastal plain of North Carolina and is considered to be endangered in the state (North Carolina Native Plant Society, n.d.). Coralbean is present in Carolina Beach State Park, located in Carolina Beach, North Carolina, and can be located along the Sugarloaf Trail.

The distribution of coralbean in the United States. Image Source: http://www.wildsouthflorida.com/coral.bean.html#.XPBnO3tG29

Coralbean in Carolina Beach State Park. If you look closely, you can see the green pods toward the bottom of the plant. Image Souce: Island Ecology for Educators Instagram (https://www.instagram.com/p/BxxlwibBZXv/)

A hummingbird collecting nectar from a coralbean. Image Source: https://www.hernandosun.com/article/springin-pollinators

This image showcases the coralbean's unique flower, as well as its green pea pods. Image Source: http://majikphil.blogspot.com/2017/05/florida-coral-bean.html

Evolutionary History

The evolutionary history of the coralbean is not widely published; however, based on some of the plant’s traits, it is possible to ponder on its evolution. Many members of the Fabaceae family are able to “fix atmospheric nitrogen via a symbiotic association with root-nodulating bacteria”, allowing the plants to obtain the nitrogen needed for their metabolism (Wojciechowski et al., 2006). Like other members of the Fabaceae, the coralbean has evolved to fix nitrogen to use as a nutrient to meet its metabolic needs, allowing the plant to thrive in nitrogen-poor environments (Allyn, 2013).

The toxicity of the coralbean, along with its coloration, are another evolutionary advantage. More of then not, bright coloration is used as a signal to other organisms to indicate that the plant is toxic and that it should be left alone. Coralbeans contain a variety of toxic alkaloids, which are found in the plant’s seeds. The alkaloids present in the coralbean have narcotic and laxative effects. Due to these alkaloids, the coralbean has been used for many toxic purposes in history, including being used as rat poison (Erythrina herbacea - L., n.d.).

Environmental Impacts

Coralbean has very few negative environmental impacts. While the coralbean is not considered to be an invasive species, it does have some invasive potential due to its ability to quickly spread and grow in new locations. In its native range, the coralbean “often reproduces into nearby landscapes” (Gilman et al., 2019). Because of this, landowners may find the coralbean to be a nuisance, especially since the presence of the plant can cause land to be deemed unfit to raise stock, such as cattle, due to coralbean’s toxicity.

Coralbean is the perfect flora to include in a native plant garden. Native gardens are advantageous because native flora are adapted to our local environment; therefore, they require less maintenance and resources, such as fertilizer, pesticide, and water, than non-native species. Native flora like coralbean also "create vital habitats that sustain our native wildlife". Most importantly, native plants do not become invasive in their native range (Thornhill et al., 2013). Various organisms will be attracted to coralbean in a native garden, including hummingbirds, butterflies, and other important pollinators.

To learn more about starting your own native garden in coastal North Carolina, visit the "Native Plants for Coastal North Carolina Landscapes" resource published by the US Fish and Wildlife Service by clicking the button below.

Native Plants for Coastal North Carolina Landscapes

A glimpse into the pod of a coralbean. Image source: http://gardeningsolutions.ifas.ufl.edu/mastergardener/outreach/plant_id/ornamentals/cherokee_bean.shtml

Coralbean. Image Source: http://majikphil.blogspot.com/2017/05/florida-coral-bean.html

Conservation

According to the North Carolina Native Plant Society, coralbean is ranked as globally secure, indicating that it is common and widespread within its native range; however, it may be rare along the periphery of its range. This rank corroborates North Carolina’s rank of imperiled, as the state is within the periphery of the coralbean’s range. The imperiled rank indicates that rarity make it “very vulnerable to extirpation from the state”. Additionally, the coralbean finds itself on North Carolina’s endangered species list (North Carolina Native Plant Society, n.d.).

In order to conserve the coralbean, human development should be limited in areas where the plant is considered to be endangered. There are currently no conservation concerns in areas where the coralbean is found in abundance.

Friends or Foes?

Smaller coralbean plants (3-5 feet) can be outcompeted for light by larger plants that create canopy cover. For example, the coralbeans found in Carolina Beach State Park were very small in size; therefore, plants such as long leaf pines, pond pines, and turkey oak trees can all limit the light that the coralbeans are exposed to. In areas, such as Florida, where the coralbean plants are much larger in size (upwards of 10-12 feet), they will outcompete smaller shrubs and grasses for light exposure.

Coralbeans provide sweet nectar for hummingbirds, butterflies, and other pollinators. The plant can be attacked and damaged by the Erythrina borer moth (Terastia meticulosalis). The larvae of this moth species bores into the coralbean stem tips, which kills the stem (Institute for Regional Conservation, n.d.).

T. meticulosalis larvae boring into the stem tip of a coralbean plant. Image Source: https://entnemdept.ifas.ufl.edu/creatures/orn/shrubs/erythrina_moths.htm

Videos

To learn more about coralbean, start the video below at 2 minutes, 30 seconds.

The video below showcases a Ruby Throat Hummingbird (Archilochus colubris) feeding in nectar from a coralbean plant.

The video below showcases the pod of a coralbean and discusses the plant's toxicity.

Additional Resources to Explore

Visit the Lady Bird Johnson Wildflower Center for an informational website about the coralbean. If you click on the green underlined terms on this website, the botanical definition appears next to the word. Link: https://www.wildflower.org/plants/result.php?id_plant=erhe4

Visit the University of Florida for an informative overview of the coralbean and detailed descriptions of each part of the plant. Link: http://edis.ifas.ufl.edu/fp197

Visit the Florida Wildflower Society for a one page printable overview of the coralbean. Link: https://flawildflowers.org/resources/pdfs/flowerfriday/Erythrina_herbacea.pdf

Visit the Florida Native Plant Society for a PowerPoint presentation about the coralbean, which provides additional information about the plant's taxonomy. Link: https://www.fnps.org/assets/pdf/pubs/erythrina_herbacea_coralbean.pdf

Visit the North Carolina Native Plant Society for additional information about the coralbean's presence in North Carolina. This website also provides images of the coralbean that were taken locally in Wilmington, North Carolina. Link: https://www.ncwildflower.org/plant_galleries/details/erythrina-herbacea

Resources Utilized

Citations

Allyn, J. (2013). Plant Profile: Coral Bean. Retrieved from http://pinellas.fnpschapters.org/index.php?id=coralbean

Erythrina herbacea - L. (n.d.). Retrieved from https://pfaf.org/User/Plant.aspx?LatinName=Erythrina herbacea

Gilman, E. F., Watson, D. G., Klein, R. W., Koeser, A. K., Hilbert, D. R., & McLean, D. C. (2019). Erythrina herbacea: Coralbean. Retrieved from http://edis.ifas.ufl.edu/fp197

Institute for Regional Conservation. (n.d.). Coralbean. Retrieved from https://regionalconservation.org/beta/nfyn/plantdetail.asp?tx=Erytherb

Lady Bird Johnson Wildflower Center. (2008). Erythrina herbacea. Retrieved from https://www.wildflower.org/plants/result.php?id_plant=erhe4

North Carolina Native Plant Society. (n.d.). Plant Details: Erythrina herbacea. Retrieved from https://www.ncwildflower.org/plant_galleries/details/erythrina-herbacea

Thornhill, R., Suiter, D., & Krings, L. (2013). Native Plants for Coastal North Carolina Landscapes [PDF File]. Retrieved from https://www.fws.gov/raleigh/pdfs/NativePlantsCoastalNC.pdf

United States Department of Agriculture. (n.d.). Erythrina herbacea L. Retrieved from https://plants.usda.gov/core/profile?symbol=erhe4

University of Florida. (n.d. A). Coralbean. Retrieved from http://sfrc.ufl.edu/extension/4h/plants/Coralbean/index.html

University of Florida. (n.d. B). Coral Bean. Retrieved from http://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/coral-bean.html

Wojciechowski, F., Mahn, J., & Jones, B. (2006). Fabaceae. Retrieved from http://www.tolweb.org/Fabaceae

Photograph Citations

Header: https://commons.wikimedia.org/wiki/File:Coral_Bean,_NPSPhoto,_S.Zenner_(9099847177).jpg

Image Carousel (in order): https://davesgarden.com/guides/articles/view/2174, http://www.thesurvivalgardener.com/coral-bean-nitrogen-fixing-native-florida-wildflower/, and https://hannah.smith-family.com/wp-content/uploads/2016/06/4591-Red-Coral-Bean.jpg.

Google Sites

Report abuse