What is the most invasive plant species in the world?

Question

for eg. Prosopis juliflora the mequit.

Answer 1

Since plants are limited by the environment they live in. There is no real answer to the question. Here are a few of these plants and where they inhabit.

Elaeagnus angustifolia (Russian olive western U.S.)
Melaleuca quinquenervia (Cajeput tree wetlands, southern Florida)
Lythrum salicaria (purple loosestrife wetlands, most of U.S.)
Ailanthus altissima (tree-of-heaven most of U.S.)
Lonicera japonica (Japanese honeysuckle eastern U.S. to Midwest)
Pueraria lobata (kudzu southeastern U.S.)
Euphorbia esula (leafy spurge Midwest to West)
Polygonum perfoliatum (mile-a-minute NY to VA and WV)
Tamarix ramosissima ( tamarisk western U.S.)
Imperata cylindrica (cogongrass Gulf Coast states)

Answer 2

take a look at your lawn, all that green grass is invasive. When you stop to think about it nearly everyone has some sort of lawn, not all lawns are composed of the same species but the most popular ones are sold world wide and distributed on nearly every continent. Most people probably wouldnt think of it as invasive but in many parts of the world the grass they grow isnt supposed to be there.

Answer 3

Can't speak for the entire world, but I volunteered in an invasive species control project in Ohio. The worse offenders were Asian Stilt Grass (Microstegium vimineum), Garlic Mustard (Alliaria petiolata), Multiflora Rose (Rosa multiflora), Tree of Heaven (Ailanthus altissima), and Japanese Honeysuckle (Lonicera japonica).
Whacking through Multiflora Rose is no fun.

Answer 4

Caulerpa taxifolia (aquarium strain), also know as killer algae, has been taking over the world's ocean coastlines at an alarming speed. It is inedible to all ocean creatures in these areas and has already destroyed whole ecosystem. The last I heard, scientists still haven't figured out how to completely destroy it, and the only strategy for preventing the spread is outlawing it's use in aquariums, early detection and the use of poisons against it. It is a huge danger to our oceans, which cover the majority of our planet. I hope they find a solution before it's too late. Check out these sites for more information: http://www.press.uchicago.edu/cgi-bin/hfs.cgi/00/13908.ctl
http://swr.nmfs.noaa.gov/hcd/caulerpa/factsheet203.htm

Answer 5

I am not sure about the world, but here in Kentucky it would be kudzu, honeysuckle (bush and japanese), tree-of-heaven, Royal Paulowina, mimosa, fescue, purple loosestrife, and oh so many more. Part of my job is to record the occurances and the amount of these plants in the western part of the state.

Answer 6

Russian Thistle

Answer 7

I would have to say kudzu because here in the south we didn't have any before a soldier brought some back from Vietnam during the war and now it is everywhere.

Answer 8

The strangler fig tree will grow right on top of another tree, sucking everything from it until its roots finally reach the ground and cover the trunk of its host.

I'm sure that's not what you meant by 'invasive', but cool nonetheless.

Answer 9

Kudzu

Answer 10

In the US, kudzu, bindweed, purple loostrife, cheat grass, knapweed, leafy spurge (Agh, just writing that makes me want to go out and buy some herbicides).