Popular for its sweet scent rather than for its hideous form, Cestrum nocturnum, commonly called night
blooming jasmine, is the most commonly sold horticultural invasive species. This sprawling shrub has pointed alternately arranged leaves, green bark, tubular white flowers and pea sized fruit with a styrofoam-like texture.
A member of the nightshade family (Solanaceae), night blooming jasmine is originally from the West Indies. The Latin species name, nocturnum, refers to night when the sweet fragrance is emitted. Interestingly, night blooming jasmine is not related to true jasmine (Jasminum spp.). Introduced to Hawaiʻi around 1871, night blooming jasmine quickly became a common ornamental. It escaped cultivation and invaded natural areas a mere seventeen years later in 1888. Like Miconia and strawberry guava, and other invasives that were brought to Hawaiʻi for their attractive qualities, night blooming jasmine has spread into natural areas. Today night blooming jasmine is considered invasive on Hawaiʻi Island, Kauaʻi, Oahu, Maui and Lanai.
Night blooming jasmine tolerates shade and grows well in moist places, making our native rainforests an appealing habitat. It also grows well on trails, road sides, ravines and secondary forests. The prolific seeds are eaten by birds and spread deep into the native ecosystem, where they remain viable in the soil for many years. This plant is self-compatible, needing only itself to produce viable seeds. The bush grows vegetatively as well, rooting from the nodes to make new individuals who reach reproductive maturity in a very short time. Night blooming jasmine can rapidly colonize an area forming dense, impenetrable thickets, shading out other plants causing fundamental changes in the natural ecosystem spelling trouble for native species. Native plants evolved over thousands of years to grow in harmony with one another, and they don’t grow well with aggressive competition.
A night blooming jasmine beginning to invade a koa forest. All it takes is a single plant to form a new population. This plant is self-compatible, needing only itself to produce viable seeds. It also reproduces vegetatively, branches and prone stems root at the nodes to quickly form a dense thicket.[/caption]Originating from our gardens and moved around by birds, night blooming jasmine is not as harmless as one would think. This seemingly insignificant shrub is actively outcompeting old growth koa and other native species around the state. Forming a dense impenetrable thicket in the understory, the koa seeds are unable to germinate resulting in a forest that can’t regenerate. The overstory of koa are all one age; when they die there will be no koa progeny to soar up into the sky, provide habitat for native fauna, recharge our ground water and provide new seeds to continue gap phase dynamics. In the fight for light and nutrients, the bush beats the native old growth tree.
Besides outcompeting with native and more desirable species, night blooming jasmine is toxic to fish, cattle and causes hay fever like symptoms in humans. The strong odor emitted at night has caused nausea, hay fever and migraine headaches to people down wind. An alluring odor to some can become a lawsuit or a call to the poison control hotline to another.
Planting Pono is the first line of defense against horticultural invasive species. Sadly, no laws exist about the sales and importation of invasive species. Mock orange, alahe’e, any citrus tree, pua kenikeni, true jasmine and fragrant olive are all noninvasive choices that smell delicious and have a much better looking form. Mahalo for choosing and alternative plant to invasive night-blooming jasmine. Mahalo for encouraging your friends, family and neighbors to do the same.