Answers For [Forecast Q2-2025] - The Invasion of Plants

Welcome to today’s biology lecture. We are going to talk about a couple of invasive plants.

What is an invasive species?

Well, an invasive plant has the ability to spread aggressively outside its native range in a new habitat.

Invasive plants can even cause economic or environmental harm.

At the same time, they threaten local plants by competing for nutrients, light and water.

Invasive species have contributed to the decline of many endangered and threatened species in the U.S.

1As many of you have noticed in your own life, some of these species outcompete other plants and take over a whole garden.

So, they have become a serious problem that both the government and the public must deal with.

2These species are often brought out of their native range by humans or birds.

They unknowingly carry the seeds with them to a new environment.

Now let’s take a look at some invasive species and see how they are affecting native environment.

3Common Broom or Scotch Broom, is a plant native to western and central Europe.

It typically grows to 1 to 3 meters tall. It is found in sunny sites.

In America, this species has become an ecologically destructive plant, especially in grassland, shrubs and woodlands.

It has a competitive advantage over native trees and shrubs in North America.

And since its introduction, it has caused not only ecological but also economic problems.

It even affected the performance of the commodity industry.

4It is estimated that it is responsible for the lost timber production which was worth $15 million US dollars last year in Oregon.

As common broom can cause such a big problem, how can we control it?

One way to start is by targeting the common broom plants that are producing fruits.

Then we need to remove these fruit-bearing trees, and that will reduce the amount of seeds added to the soil each year.

5Another way is biological control, like introducing some insects from its place of origin.

They will disturb the growth of this invasive plant.

Next, there’s Japanese Barberry, which is native to Japan and eastern Asia. It tolerates a wide range of soil and moisture conditions.

It is found along woodland edges, roadsides, stream banks, old fields and forests.

6This species was brought to America from Russia in 1975 , and it is now widely seen throughout the US.

7It has yellow flowers and bears bright red fruits. It’s used widely as landscape and hedge material.

It has been replacing native species in America.

Furthermore, the plant can change soil condition and cause diseases to plants like wheat.

In recent years, Japanese barberry has been recognized as an invasive species in many parts of the eastern United States.

A variety of techniques including both mechanical and chemical controls may be effective in dealing with this species, but the exact method should be tailored to the specific conditions on the site.

Buckthorn or Common Buckthorn, is a species of tree-like plant which usually grows two to three meters tall, but it occasionally reaches up to 10 meters tall.

8It has smooth, dark green leaves.

Common buckthorn produces berry-like black fruits in late summer and autumn.

It is invasive in many parts of the western part of the United States.

It is native to Europe, and it was introduced to North America in the early 19th century.

It causes damage to local soil and plants.

Buckthorn can spread widely with the help of birds that eat its fruits.

9They then carry the seeds long distances along their path of migration.

What can we do to control it?

First, we need to learn how to identify common buckthorn.

10It is different from sea buckthorn, which is a plant that can be used to treat serious digestive problems.

Then, we should avoid using it in gardens and landscape.

You can contact the Invading Species Hotline if you find common buckthorn in the wild.

So, let’s look at some pictures of these…