The term “yellow jasmine” is a common name applied to several different climbing plants with bright yellow flowers, causing frequent confusion. This ambiguity represents a significant safety distinction, as some plants called yellow jasmine are harmless while others are highly poisonous. This information clarifies the botanical identities behind this name and outlines the implications for gardeners and homeowners.
Identifying the Primary Contenders
Plants commonly called yellow jasmine fall into two distinct genera and families. The non-toxic varieties belong to the Jasminum genus (true jasmines), members of the Oleaceae (olive) family, originating primarily from Asia and Europe. The most common yellow-flowering example is Winter Jasmine (Jasminum nudiflorum), a deciduous shrub or scrambling vine.
The toxic plant most often referred to as yellow jasmine is Carolina Jessamine (Gelsemium sempervirens), which is not a true jasmine and belongs to the Gelsemiaceae family. This species is an evergreen, twining vine native to the southeastern United States, ranging from Virginia to Texas and Central America. Distinguishing the two is possible by observing leaf arrangement: true jasmines have trifoliolate (three-leaflet) leaves, while the toxic G. sempervirens has glossy, lance-shaped leaves arranged oppositely along the stem.
The Critical Safety Distinction
The core difference lies in the potent neurotoxins contained within Carolina Jessamine (Gelsemium sempervirens). This plant produces highly toxic indole alkaloids, including gelsemine, gelseminine, and sempervirine. These compounds are present in all parts of the plant—roots, stems, leaves, and flowers—and the nectar is also poisonous.
The primary mechanism of action for these toxins involves the central nervous system. Gelsemine acts as an agonist on the mammalian glycine receptor, an inhibitory neurotransmitter receptor in the spinal cord and brainstem. This over-activation causes a strong inhibitory effect on nerve signaling, leading to progressive muscle relaxation and paralysis.
Ingestion of even small amounts of Carolina Jessamine can rapidly lead to severe poisoning in humans and pets. Initial symptoms often appear quickly, usually within an hour, and include dizziness, blurred vision, and difficulty swallowing. This progresses to profound muscle weakness, seizures, and respiratory depression. The paralysis of the respiratory muscles is the cause of death, making ingestion of this plant a medical emergency requiring immediate attention.
Common Landscape Uses and Cultivation
Both types of yellow jasmine are popular choices in landscape design, despite the health hazard of the Gelsemium variety. Carolina Jessamine is prized for its vigorous, evergreen nature and the profusion of intensely fragrant, trumpet-shaped flowers that appear in late winter to early spring. It is commonly grown in USDA hardiness zones 7 through 10, thriving best in full sun to partial shade and moist, well-drained soil.
Gardeners use Carolina Jessamine as a classic twining vine, training it up trellises, fences, and arbors, or allowing it to sprawl as a dense, evergreen ground cover. The non-toxic Winter Jasmine (Jasminum nudiflorum) is valued for its hardiness, surviving in colder zones down to zone 6, and its ability to bloom in the middle of winter. This deciduous plant is often used on slopes for erosion control or as a weeping, sprawling shrub, though its flowers are non-fragrant.
Because of the high toxicity of Gelsemium sempervirens, careful consideration must be given to its placement, especially in yards frequented by children or pets. If planted, it should be located far from areas where accidental ingestion is possible, and handling should always be done with gloves. The Jasminum varieties are safe to handle and do not pose a poisoning risk.