English
ivy, Hedera helix, is an invasive
species in Washington and Oregon. It takes over areas very easily and shades out other plants.7 It also
climbs up trees adding weight and weakening them. It also spreads very rapidly
and is ground cover as well as being a climbing plant.1 Because they have very
shallow roots and crowd out other ground plants soil can become eroded and
poor.8
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| Synthetic figure: distribution of English ivy in the US |
The
plant was native to Europe and was most likely brought over as an ornamental.3 Although
the ivy has been found on both coasts, it is very invasive in the Pacific
Northwest.5 Many people do not understand how destructive this plant can be,
although it has been qualified as a noxious weed in Washington.10 One of the
reasons it is so invasive in Washington state is because it is particularly
good at growing in shady areas.6 This could also be why it is popular as an
ornamental plant that people keep around.
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| Trees covered in ivy |
Although
it is very fast spreading it is also easy to kill. Its roots are very shallow
and when pulled out or have an herbicide used on it the plant will die.
However, it is often hard to get rid of because it has such a large
distribution and as ground cover it is intertwined with many other plants.
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| Ivy on a brick wall |
One
of the most dangerous things about English ivy is that it dramatically
decreases biodiversity. When the ivy gets established it makes it difficult for
small plants to survive around it and eventually it will even take down trees.9
To prevent spreading it is essential to ensure the ivy does not bloom, which
happens when the ivy gets enough sunlight.6 To stop that the ivy must be taken
down before it climbs high enough on trees.
