We’re knee-deep in colorful fall foliage at this point, and I hope you enjoy it as much as I do. Autumn is my favorite season, but it’s also associated with the next plant in our invasive species series; autumn olive. Autumn olive (Elaeagnus umbellata) is a deciduous shrub that, like many other invasive shrubs, was introduced in the US as an ornamental, and found itself spreading at an enormous rate. With its spread, of course, come the negative impacts often associated with non-native, invasive plants.

Junk Food For Wildlife

Autumn olive isn’t necessarily the most nutritious food source for wildlife. The abundance of fruit autumn olive produces can cause birds to fill up on empty calories. The berries contain low amounts of protein and fat, but are high in carbs, which led my friend to aptly nicknaming the plant “Autumn Olive Garden.”

Dense stands of autumn olive outcompeting would-be native species. Photo credit: Chris Evans, University of Illinois, Bugwood.org

On top of that, the plant can outcompete and displace native plants by shading them out or altering soil chemistry. This reduced biodiversity can be detrimental to water quality, soil health, and of course, wildlife health; a lot of the things we love here at the Alliance!

Spot the Spots

The upper side, and noticeably more silver underside of autumn olive leaves, along with the fruit spotted with scales. Photo credit: One Acre Farm

Around this time of year, autumn olive should be relatively easy to identify. The plant has plenty of small, red-brown fruits, spotted with brown or silvery scales. Another quick way to recognize the species is examining its lance-shaped, shiny, leaves. The underside of autumn olive leaves have a silver-green appearance with brown or white spots similar to the scales on the berries. The plant’s leaves also have a very wavy shape, similar to another junk food favorite, the potato chip.

The wavy leaf margins of autumn olive. Photo credit: KENPEI

Don’t be Fooled by Other Olives

You might see Russian olive (Elaeagnus angustifolia) at a glance and think it’s autumn olive, but the Russian variety’s leaves are narrower, with a silver-white appearance on both sides. Russian olive fruit is also generally lighter in color, usually yellow or silver, with a mealier texture.

Thorny olive (Elaeagnus pungens) can also be tricky, as its leaves are similarly wavy. A good way to determine this lookalike, though, is that thorny olive has much more prominent scales on the upper side of leaves. Either way, all three olive species are invasive, so take note of where you see them! Learn more about the characteristics of autumn olive and its lookalikes below.

A Prolific Seeder

Not only does autumn olive’s nitrogen-fixing abilities allow it to spread in unfavorable soils, it’s a prolific seed producer. One plant can produce up to 200,000 seeds each year, and those birds filling up on the fruit spread those large amounts of seeds wherever they travel.

The abundant speckled fall fruits of autumn olive. Photo credit: Wendell Smith

A Tough Management Prospect

Recognizing autumn olive before it has a chance to establish is always great, as hand pulling seedlings is an easy and effective way to prevent its spread. Cutting or burning, however, can actually aid the spread of this pesky shrub. Autumn olive germinates easily, so it loves being thrown around by weed whackers or invigorated by fire.

In any case, managing the plant before fruiting will prevent the spread of its infamous, abundant seeds. Due to the tough nature of the plant, though, herbicides are sometimes necessary to eradicate it, using the cut stump method from summer to winter.

An Ounce of Prevention

When thinking about invasive species, Benjamin Franklin certainly hit the nail on the head. Once established, invasive species are more difficult and more expensive to eradicate. The best thing we can all do is establish robust, diverse native plant populations that have a fighting chance against tough shrub seedlings like autumn olive. Always be on the lookout for invasive seedlings, and stop the problem before it starts. No matter where you’re looking to plant natives, whether it be a wet area, a shady area, an area with poor soil, and everything in between, the Alliance’s Native Plant Center can help you pick the right plant to well…plant!