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Activists Fight Invasive Weeds - 2003-04-25

One consequence of globalization is the unwanted spread of plants, animals and microbes that can disrupt nature’s balance. Invasive species can impact economies and even pose health threats. VOA-TV’S Tim Wardner found a group in the U.S. Pacific Northwest trying to control invader plants.

NATURAL SOUND: Sandra Diedrich shouting
“Dead ivy, dead ivy, dead ivy.”

Sandra Diedrich is assembling her troops. The invaders are dug in. The enemy is ivy.

NATURAL SOUND: Sandra Diedrich shouting
“It just erupted, exponentially erupted, and started creating these whole huge areas that we started describing as ivy deserts.”

Sandra Diedrich organizes volunteers to clear English ivy from Forest Park in the city of Portland, Oregon. English Ivy is a plant species not native to the United States. Its rapid spread and aggressive nature has classified it as an unwanted ‘invasive plant’ in the Pacific Northwest.

“It can get under the canopy of a natural area or get under the canopy of a forest and grow undetected for a long time until it has established an ivy desert for itself, shrouded the trees and the trees are literally nothing more than a standing snag.”

Several times a week, volunteers go into Forest Park to cut ivy vines and try to control the growth that has come to overwhelm sections of the park. According to volunteer Bruno Precciozzi, their efforts have made some headway.

“All these trees with browning branches on their trunks are trees we have removed ivy from, or cut the ivy off the bases. If you can imagine, all the trees with browning ivy, when we first started, had live ivy on them, pretty mature ivy. You can see why we call this area the ‘heart of darkness’.”

Modern travel and global trade have accelerated the movement of plants that unbalance ecosystems, a serious worldwide problem according to Ernest Delfosse who studies weeds for the U.S. Department of Agriculture.

“Virtually every country in the world has weeds from somewhere else in the world.”

And, we are losing the battle says Mr. Delfosse.

“Invasive species as a whole cost the country close to $140 billion dollars a year.”

The spread of weeds is likened to an explosion in slow motion.


This crew in Virginia is cutting a grove of fast-growing bamboo that interferes with power lines. Development has also accelerated the growth of invasive plants as seen in large overgrowth areas along highways.

“Plants will grow in areas that are disturbed.”

Most people think “green is good.” Horticulturist Joan Feely says most people are unaware of nonnative plants.

“You think you’re seeing the natural woods as you walk along, but you’re seeing a bit of North America in your trees and a lot of China and Eastern Asia in your understory.”

Once a small outbreak spreads, like the ivy in Portland did, eradication is not likely and control is an uphill battle.

NATURAL SOUND: Volunteers shouting