Whether you’re a farmer or a home gardener, a lack of knowledge regarding invasive plants can cost you dearly. These plants can hijack your plants’ nutrients, proliferate, and damage the ecosystem. But since there are various invasive plants, we will focus today on two commonly confused species: autumn olive and Russian olive.
These plants have become quite invasive in many parts of the US and Europe. Moreover, they can be quite challenging to get rid of once they take hold.
Therefore, in this post, we will discuss:
- What these plants are.
- Autumn olive vs. Russian olive: the key differences.
- Are these plants useful?
- How to eradicate these plants
But before that, let us first understand what invasive plants are.
What are Invasive Plants?
Invasive plants are types of plants that are non-native in a particular region. They spread at an incredibly fast rate and harm the ecosystem. They compete with native plants for resources like water, nutrients, and sunlight. This impacts the growth of native plants and alters the natural ecological processes.
Invasive plants can also affect the economy by harming crops, damaging infrastructure, and blocking natural waterways. Some invasive plants can also be toxic or allergenic for humans and certain animals.
Autumn and Russian olives have an interesting history. They weren’t considered invasive when they were first brought to the United States in 1830. At that time, they were meant to provide food and cover for wildlife such as game birds. Other intended uses of these plants were erosion control, strip mine reclamation, road bank stabilization, shelterbelts, and ornamental use. The horticultural industry took an active part in promoting and selling these plants.
Both these plants are from the family Elaeagnaceae, which has 70+ species. These plants are upright and deciduous shrubs that can reach up to 20 feet in height. However, with time, these shrubs became invasive for farmers and gardeners, posing serious threats to the ecosystem. Due to their fast growth and untimely management, these plants can become hard to control and eradicate.
Here’s a quick look at how autumn olives and Russian olives can harm the ecosystem:
- Russian and autumn olives can cause nitrogen fixation in the soil, creating a nitrogen cycle imbalance. This imbalance can alter/damage native plant communities and reduce biodiversity.
- Birds love the small fruits of autumn and Russian olive plants. When birds eat these fruits, they become carriers of seeds and take them far and wide, resulting in a greater and faster spread of these invasive shrubs.
- These shrubs are dense and spread out, crowding out and limiting the sunlight for the native plants.
- The shrub can easily resprout if cut.
- Once these shrubs become dense and spread out, they are tough to eradicate.
- They can cover large, open areas like prairies, forests, and floodplains if allowed to grow. They can also thrive well in partial shade.
Botanically known as Elaeagnus umbellata, autumn olive is an invasive shrub most commonly found in North Carolina today. It is also ranked as a “severe threat” by the Tennessee Exotic Pest Plant Council. Autumn olive is also known by other names such as:
- Japanese silverberry
- Umbellata oleaster
- Autumn Elaeagnus
- Spreading oleaster
This plant is native to Southeast Asia and some parts of the Himalayas and Japan. Today, autumn olive is regarded as an invasive plant in many zones of Europe and the US. It can spread quickly and outrun greeneries. It is identified by its vivid red berries, cloudy and fragrant yellow-white flowers, and spines/prickles along the branches.
Here’s a detailed look at this plant’s features.
Autumn olive is a bushy shrub that can reach a maximum height of 20 feet. Apart from its invasive properties like nutrient restriction, it can block sunlight access to other plants due to its height.
An autumn olive leaf is green and oval-shaped with silvery scales. When the plants are relatively younger, the silvery scales are visible on both sides of the leaves. However, as the plant matures, these scales are visible only on the lower surface. Some autumn olive plants may have brown scales on the lower side instead of silver.
Autumn olives have white-yellow or cream-colored flowers that are present in clusters. The flowers have a sweet fragrance and look beautiful against the deep green foliage.
If you can’t find a difference between autumn and Russian olive plants based on other features, focus on the fruits. The autumn olive plant features vibrant bloodshot berries, easily distinguishable from the green fruits of the Russian olive plants.
The fruits are loved by birds and are also edible for humans. The plant sets fruit during late summer or fall. The berries contain lycopene, a natural compound also found in tomatoes with many health benefits.
Ultimately, the plant is a formidable competitor, so its invasive quality should not be underestimated compared to the fruits it produces.
Botanically known as Elaeagnus angustifolia, the Russian olive is a quickly-maturing invasive shrub found in many parts of the US and countries like Germany. It is also known by other names such as:
- Persian olive
- Silver berry
- Wild olive
Its branches are shiny, thorny, and light brown. It is native to Europe and Asia, where it is commonly found in mountains, deserts, grass plains, and generally drier habitats. In non-native territories, it is commonly found in marshes, floodplains, streams, near river banks, and irrigation ditches. It can thrive in poor soil conditions, which makes it an outstanding competitor.
Its fruits provide nutrients for birds and other mammals. Livestock also eats their leaves, and beavers use their fallen branches to construct dams.
Russian olive is a deciduous shrub that can reach 10-25 feet.
A Russian olive leaf is relatively narrower than the leaf of an autumn olive. The upper surface of the leaf features tiny white hairs and a dark green color. The lower surface of the leaf is densely covered in scales and has a light gray color. The stems are also covered in tiny white hair, which gives them a shiny hue. However, they turn brown as they mature.
The flowers of the Russian olive plant are much yellower than the autumn olive. Moreover, unlike autumn olive plants, they don’t form in clusters with many flowers. Instead, the Russian olive plant features 2-3 flowers on a single leaf axis. The flowers are approximately 1.5 centimeters wide.
The flowers also have a sweet fragrance and bloom between May and June.
The fruits of Russian olives go through different colors depending on their age. When they first form, they are white. As they mature, they turn a light green/yellow color. Apart from the color difference, the shape of the Russian olive fruit is also different from the autumn olive fruit.
The fruit is olive shaped and about 1 cm long. It is produced in large quantities and is edible for humans. The seeds are also large, and the fruit forms between August and October.
Even though these plants are highly invasive, they have also been used to benefit humans and society. However, check with the local horticultural authorities before planting them in your backyard. Due to their invasive nature, planting these shrubs is not allowed in certain regions.
Here are some potential uses and benefits of autumn and Russian olives:
The fruit of autumn and Russian olives are edible for humans and certain animals. Game birds enjoy their fruit, while humans can consume them in different ways, such as jams and jellies.
Autumn and Russian olive plants have been used in traditional medicine for digestive disorders, flu, and colds.
When these plants were first brought to the US, they served landscaping and erosion control needs. Their hardy nature makes them drought tolerant and poor soil conditions.
Once established, these plants can be a challenge to eradicate. Prompt action is important, and you can use the following ways to nip the evil in the bud.
Also known as manual control, it refers to cutting the plants or pulling them by the roots. This method is only applicable when the shrubs are young and small. Moreover, cutting these invasive species has proven inefficient, so the best way to eliminate them is to pull them out.
Refers to using chemicals such as herbicides to get rid of plants; it has proven to be quite effective. However, care must be taken when applying herbicides on tall shrubs, as the particles carried through the air can also damage other plants nearby. Herbicides can also be harmful to wildlife.
Controlled burning can be effective when the shrubs cover large areas like plains, and no other type of vegetation is present. However, burning alone is insufficient as these shrubs can quickly resprout.
Goats and sheep can readily eat the foliage of autumn and Russian olive plants. They can stand on their hind legs to consume taller plants(as much as 5 feet), and they don’t mind thorns that much. It can be an effective strategy to create space for movement before using other methods like herbicides or pulling.
Lastly, you should dispose of the plant material properly so it doesn’t grow back.
With this information, you’ll find it easier to identify and differentiate between autumn olive and Russian olive. The key to controlling these weeds is to stay vigilant and eradicate them when they are young. You should be more watchful if you live in the regions where these species have become invasive such as parts of the United States, Europe, and England.
Lastly, the methods of eradication mentioned above may not be sufficient on their own. Farmers and gardeners may have to adapt and combine multiple techniques to effectively control the growth of these invasive species.
Frequently Asked Questions (FAQ)
What is the difference between an autumn olive tree and a Russian olive tree?
The most noticeable difference between the Russian and autumn olive is the fruit. Additionally, autumn olive has relatively broader leaves than Russian olive. The Russian olive has silvery scales, while the autumn olive’s scales can be either silvery or rust-colored.
Are autumn olives safe to eat raw?
Birds love and wait for the autumn olive fruit, and it is also safe to eat raw for humans. It also has many health benefits, and people typically use these fruits in jam recipes.