Autumn olive: a ostentatious ornamental, an irritating invasive, a refreshing recipe, and perhaps a pollinator's paradise?
On a gray, unusually warm afternoon in the middle of January, a passerby along the trails of the Duke Forest might have overheard two researchers shouting back and forth to one another. Disappointing remarks such as, "Could it be this brown, dead-looking bush? Or is it one of these other similarly spiky leafless twigs?" to excited cheers like "These leaves are without a doubt undulate. Hey! I have never used the word before and I found autumn olive" drifted around the forest for all to hear. Autumn olive (Elaeagnus umbellata) has been on my mind of late because an undergraduate student at Duke University is starting an independent research project on it. She hypothesizes that the presence of autumn olive flowers affects the pollinator community of native flowering herbs. Furthermore, she hypothesizes that the change in the pollinator community could potentially reduce fruit and seed production of the natives. We are going to start field work in about one month to find out if her hypothesis is correct, but first, we are learning more about this plant.
Autumn olive is an invasive plant and was introduced to the United States from Asia in the 1830s. The term invasive sounds threatening, so why did people bring this plant to the United States and what is so bad about it? It was promoted as a way to control erosion and provide wildlife habitat in disturbed areas. Around the 1950s, autumn olive became widespread. The problem with autumn olive is that it can grow in areas where resources, including water and nutrients, are quite scarce. The ability of autumn olive to grow in these poor habitats allowed it to rapidly outcompete native plants. Additionally, this pesky plant grows quickly and shades out smaller grasses and forbs growing nearby.
It sounds like the autumn olive situation is all doom and gloom, but what can we do about this problem? First and foremost, do not purchase autumn olive for your yard. Although it is not illegal to sell or buy this plant in many states, it is best practice not to buy non-native plants. If you have autumn olive in your yard, remove the entire plant, including the aboveground plant material and roots. If mechanical removal is not an option, herbicides are also often used to eradicate autumn olive. If you see autumn olive in a neighbor's yard or in the woods, you can still help reduce its spread by collecting the berries (with permission) and using them in a recipes including jam, fruit leather, and pies. It is important to process the autumnberries and not to eat them raw. Killing the seeds prior to eating them reduces the chance they will end up back in the environment.
If we know this plant is a problem and we should remove it, why bother spending time researching it? Although eradication efforts are underway in many places, autumn olive still exists. Understanding how this invasive plant interacts with natives for living resources, particularly pollinators, its important for predicting future responses of native plants to non-native plants. Right now, we are in the beginning stages of this research project and have been speeding time learning how to identify this plant. (Un)fortunately have come across many plants to work with. Stay tuned for our results!
*Photos were taken by Melina Keighron in Jan. 2017. Positive identification of this plant is pending. Do not collect berries from plants based on the photos above.
Resources about autumn olive: