6 Of The World's Most Invasive Plant Species

During the 1900's, people would go on vacation and they would see native species that they believed to be incredibly beautiful. Talk of these mystical plants would travel, and soon the seeds of these magical rooted beasts were brought over to various countries and planted in gardens. Unfortunately, as these people brought these luscious plants into their yards, they introduced these species to an entirely new world.

It's the new species vs. the native species, and the new guy has an advantage; no predators equals easy domination. Some don't have natural predators, others use various animal species to transport their seeds around the world. These 6 plants are ready to take it all.

6 Miconia

Via; www.invasive.org

A tree known as the “Purple Plague of Hawaii” is a small tree native to rainforests. It was introduced to Tahiti and Hawaii as an ornamental tree in the 1960’s, as it is a small and beautiful tree with large dark green leaves that feature an iridescent purple underside and dark purple veins. The flowers are a very lovely white or pink, while the berries are purple or black when ripe. With a height of 15m, the tree has become incredibly invasive, dominating over half of the island of Tahiti.

Via: de.wikipedia.org

The large, complicated root systems have caused many landslides, and they have managed to completely shade out the native plants that normally cover the island’s forest floor. Also described as the “Green Cancer of Tahiti”, the species only needs a few plants to completely take over a forest from the native species. Each tree has thousands of flowers, with many seeds in each berry. Miconia can be found in Brazil all the way to Southern Mexico, and behaves as a forest understory, pioneer species. Tahiti has taken to bulldozing their forests and trying to encourage native species to reestablish themselves on the island.

5 Kudzu


Via: http://www.invasive.org/browse/subinfo.cfm?sub=2425

This amazing species has become a very serious problem in many countries including Vanuatu, Fiji, Australia, New Zealand, Italy, Canada, and the United States. The vine is native to Japan and Southeast China. Kudzu was introduced to the U.S. in 1876, as an ornamental vine due to its sweet-smelling flowers, strong vines, and large leaves. Along with the beauty and growth speed, the vine could be used for medicine, basketry, animal food, and the roots could be foraged for various foods and beverages. Kudzu also has incredibly strong roots that not only form erosion control, but also aid in the improvement of the soil. Unfortunately, even with all the great benefits of the fast growing vine, it out-competes native species for resources and can completely dominate an area in a very short period of time. The vine has completely dominated Georgia, U.S.A, and has reached the north shore of Lake Erie, positioning itself near Leamington, Ontario. Known in the States as “the vine that ate the South”, it continues to reach for world domination.

4 Caulerpa Seaweed


Contrasting to other macroalgae, this seaweed is much more like a dry land plant than an underwater one. Caulerpa Seaweed grows in the form of a green stalk with many leaves extending out, much like a pine tree. The leaves are similar to other seaweed with its slimy texture, but the plant not only crowds out native species, it doesn’t supply the water with the nutrients that normally makes algae so good for underwater ecosystems. Along with being completely unhelpful to the other living organisms, it is entirely inedible to everything. It stores a particular toxin in its leaves that is harmful to all that consume it. Discovered in 1980, German scientists noticed that the seaweed thrived in cold-water environments and decided to try an experiment with the plant. With cross-breeding and exposure to ultra-violet rays, they managed to create an entirely new Caulerpa Seaweed that was even hardier. This was the form that managed to be released into the Mediterranean. Described as the “Killer Algae” the plant quickly consumed 30 kmin just 4 years. The only benefit to the invasive species, was that in the areas that were densely populated by the overbearing plant, the pollution levels of the water, was somehow reduced. Researchers in France have discovered a small aquatic slug that eats the seaweed, and there are plans to introduce them into the water.

3 Hottentot Fig

Via: stephens-views.blogspot.com

A ground covering plant, this little guy was also introduced as an ornamental ground cover and to prevent the erosion of sand dunes. It has since escaped and taken over parts of the Mediterranean, Australia, California, New Zealand, and Ireland. Known as the Ice Plant, it prefers dry, rocky hillsides similar to their place of origin, Namaqualand, South Africa. They also produce an edible fruit that is eaten by many animals, including the Black Rat, another invasive species that spreads the seeds of this plant through its feces. The plant creates an impenetrable blanket over the ground, preventing natural vegetation from getting any sunlight, essentially snuffing out the native species. The removal of these plants is tedious, with hand pulling the plants out of the earth, or tearing up the land with large machines.

2 Cheatgrass

Via: nativeplants.wordpress.com

Introduced into the United States to feed livestock, Cheatgrass has fully managed to establish itself all over the country. Though it has managed to prevent erosion since its introduction in the 19th century, this plant competes against native vegetation to the point of completely changing the health of the soil. Cheatgrass can be identified by its thin and hairy leaves, which often reach a length between 2-6 inches.


The stalk can grow as tall as 24 inches, and the seeds are narrow and fluffy. The biggest threat that this plant poses is its love of starting fires. It has dramatically changed the fire cycle in many Cheatgrass populated areas, and are a great source of fuel for fires. This has caused the growth of native shrubs to be diminished to the point of the shrubs not being able to establish themselves at all.

1 Giant Hogweed


Quite possibly the newest most terrifying stationary species on the planet, Giant Hogweed has become a huge problem that is rapidly spreading across Canada. Also known as Giant Cow Parsnip, this plant packs quite a punch if you get any of its sap on you. Ultraviolet light activates a toxin in the sap that causes severe dermatitis, resulting in extreme burns when exposed to the sun within 48 hours after contact. Purplish scarring can happen that can last for many years, and if the sap comes into contact with your eyes, cases of temporary and permanent blindness have been reported.


The flowers resemble Queen Anne’s Lace, which is part of the reason why they were purchased for ornamental gardens. Its course hairs, purple tinge, extreme size, and hollow insides can distinguish the stem of the appropriately named “Summer Plant from Hell”. Hogweed can reach an impressive 15-20ft, with a stem diameter of 2-4 inches, and make they birth in ditches, gardens, and the banks of streams. This perennial has spread across Europe, United Sates, and Canada.

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