STOP THE INVASION – AUTUMN OLIVE
Authored by Erin Oakley
If you’ve driven down any highway in Michigan, you’ve seen autumn olive whether you knew it or not.
Native to Asia, autumn olive (Elaeagnus umbellata) was introduced to the United States in the 1830’s. Its purpose was an ornamental as well as use in creating wildlife habitat and erosion prevention.
It matures quickly, coming to fruit bearing age in just three years. Autumn olive has oval leaves with a pointed tip, and wavy margins, the top is bright green while the bottom is a silvery green and are 2-4 inches long. Autumn olive fruit, which are red when ripe, are high in antioxidants and vitamin C, the seeds are often spread by birds and mammals causing this shrub to spread like crazy. The fruit stays on the shrub late into the winter and offers nutrients when all else is dead, unfortunately it also causes spreading at a more rapid pace. It thrives in full sun, but will still produce fruit in moderate shade, as well as many different soil profiles, making just about any place an ideal location for this invader to conquer.
The main problem with autumn olive is that it leafs out early and keeps leaves late into the fall, shading out other native plants, it can also grow 20 feet tall and 30 feet wide. It also has nitrogen fixing root nodules, meaning that it breaks down compounds into simple nitrogen, which causes problems because our native plants are adapted to survive with low nitrogen levels. Autumn olive can also increase the nitrate levels in bodies of water, especially rivers and streams, if it is close enough to the bank. Research shows that it is not a victim of deer browse; it grows to approximately the same height in an exclosure as outside, while the native plants outside the exclosure are much smaller than those inside the exclosure.
Autumn olive is hard to get rid of as when it is cut or burned it it sprouts vigorously from the root crown (where the stem comes out of the ground). A mature shrub can produce up to 30 lbs. of fruit per year, with is over 66,000 seeds. The seeds have at least a 90 percent germination rate with a chilling period, but still have a 70 percent germination rate without the chilling period. Since the germination rate is so high it is often seen in large clumps, especially in highway medians. Once established in an area it is nearly impossible to get rid of it. If the plant is young, repeated pulling or cutting could control or at least slow it the growth, but this is mostly ineffective once established. When pulling up an autumn olive the roots must also come out to prevent resprouting. If the plant is cut or mowed an herbicide should be applied shortly after to prevent resprouting, mowing should also be done in open areas to keep seedlings at bay. Goats grazing can defoliate branches up to five feet, eventually causing the shrub to die. On large infestations of autumn olive herbicides can be used, but take into consideration the proximaty to water/wetlands, how it will affect native vegetation in the area, soil erosion, and if the selected herbicide is even effective on autumn olive.
This article was funded in part with funds from the Michigan Invasive Species Grant Program through the Departments of Natural Resources, Environmental Quality, and Agriculture and Rural Development
how did it get here?
It was brought here by people from Eastern Asia, I think.
Augh – it was not brought by people from Asia per se. Also, deer do not readily eat it (this was what DNR thought when they introduced it to state forests).
It was brought here in the 1830s – people love bringing exotic plants. It was thought to be a good “bush” for hedges. It was largely spread by conservation groups that sought to control soil erosion and such – introducing it to forests. It was believed the plant would provide food for native wildlife such as birds and deer. This was deemed important in many areas impacted by the deforestation following the rebuilding of Chicago after the great Chicago fire in 1871 – so the plant really took off around the early 1900’s, and was recognized as an issue in the 1940s. The fruit is edible by people and birds alike – the birds spread the seeds. A single bush can easily produce 20k seeds a year.
It’s a terrible plant – can only be controlled by removal or poising (which should be limited due to environmental impacts). It also spreads readily – even a plant pulled from the ground, but left in contact with the soil can grow new roots and continue. Even the small roots remaining from an uprooted bush will likely grow a new plant.
Removing it takes a lot of effort – but it is worth it. Many of the species native to area are pushed out due to the plant. Take for example grouse, pheasant, or quail – each of these relies on the native grasses during winter time (used for cover and digging through snow for grains). But autumn olive can make the soil inhospitable to these native grasses due to the Ph and nitrogen – even after a bush is removed it takes some time for native plants to recover the area.
There are several species from Asian (Japan, Korea, and China) that are causing issues (such as Asian Bittersweet (Japan/Korea; celastrus orbiculatus), Autumn Olive (elaeagnus umbellata), multiflora rose (Japan/Korea; rosa multiflora; introduced in 1866), etc).
I would emphasis that one should take the effort to learn the species. For example, there are native species of rose – these should remain. [FYI, multifloral rose has curved thorns; natives have straight thorns).
Looks like holly. The deer ate all my holly. They may eat this also. Margaret
We have been trying to cut and treat our land but need help as this tree has taken over and killed our good trees. The DNR gave seeds to our neighbor and my brother and said to plant them. I can not believe this happened. How can I get help for the removal of the trees?
Back in the early 1990’s these were given out by conservation clubs. I remember getting 4. Did not know their history.
Now I see them everywhere. Our new place has hundreds of these bushes. I have been pulling them out in my back yard. The roots send off runners, like the brier’s do.
I’m going to try some of the recipes, wish the news above was better.
I’m sure they worked good for what they brought them over for, they smell great while flowering, the berries are pretty and call in birds, grow anywhere and as a hedge/screen, they are thick and have thorns to keep people from pushing through them easily.