Monday, June 7, 2021

Pacific Northwest invasive species

English ivy taking over

On my walk back home from the coffee shop in the mornings, I pass by this bench and pretty green area, which is now covered with English ivy (Hedera helix). Although it's pretty, it is invasive. See how it's climbing up the bench? And the entire ground cover is now ivy. This is one of several areas of ivy I see on my walks. It reminds me of kudzu, which I am familiar with from seeing it take over huge swaths of trees in southern states. (That article tells of how the kudzu invasive species, Japanese arrowroot, came into the country.) 

But for now, I'll concentrate on English ivy and how it got here. This article on invasive species tells the tale.

English ivy is an aggressive invader that threatens all vegetation levels of forested and open areas, growing along the ground as well as into the forest canopy. Vines climbing up tree trunks spread out and envelop branches and twigs, blocking sunlight from reaching the host tree’s foliage, thereby impeding photosynthesis. An infested tree will exhibit decline for several to many years before it dies.

So, even though it's pretty, and came here as early as the 1700s, it's not native, and it's something we should cultivate. My friend Peggy long ago showed it to me in the forest and we pulled some out while we were walking. I also learned that it can cause skin irritation in sensitive individuals, but if ingested it's pretty awful. (Don't worry, I won't try it!)

Another invasive species around here is the Himalayan blackberry. I remember when we first moved here and I discovered the sweet, heavy fruit on these plants, I was enchanted. Then I found out that it is not quite the innocent fruit it appears to be. 

Contrary to its common name, Himalayan blackberry (HBB) is a native of Western Europe. HBB was probably first introduced to North America in 1885 as a cultivated crop. By 1945 it had naturalized along the West Coast. HBB occurs on both acidic and alkaline soils, mainly in areas with an average annual rainfall greater than 76 cm (29 inches) at altitudes up to 1800 meters (6000 feet). 

This information comes from a PDF document entitled, "Controlling Himalayan Blackberry," and I learned that it too is very difficult to eradicate. We certainly have enough rainfall around here to entice it to grow. Learning all this doesn't mean I'll stop gathering and eating these blackberries when hiking, but I now have a healthy respect for their ability to take over other species. If only they weren't so delicious!

:-)

17 comments:

  1. Yes most vines can become cumbersome if not controlled. Here along the coast of Texas it's a "tree" they are trying to eradicate...Brazilian pepper tree.

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  2. We had small house on the Washington coast years ago that was not used for years and succumbed to blackberry vines. You couldn't even tell a house had been there. I have to chuckle when people in my intermountain area cultivate blackberries. I'd never heard of such a thing.

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  3. Invasive species can take quite a toll.

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  4. The invasive species ae much smarter than we are. Dandelions are considered native by some people now.

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  5. Ooh, it does sound a bit like Kudzu. That stuff is scary. As for the Blackberries, too bad eating them doesn't stunt them.

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  6. I also note in your photo another invasive species - the rhododendron. We have swathes of them taking over natural areas and although they have beautiful flowers they have to be controlled and removed. Brambles, as we call the wild blackberry, is very difficult once it takes hold and grows so quickly.

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  7. One year at the cottage, I took pics of a number of plants and then looked them up in a resource book. IIRC there were 5 plants that I was investigating, and at last 4 of them were exotic, ie from elsewhere. I don't think any were considered invasive, however.

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  8. Wild cucumber is invasive here. Last year on the trail we saw an area of trees covered with the plants and this spring everything was dead in the area. Invasive species are a threat for sure.

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  9. English Ivy and Kudzu are invasive... and I know that is a problem. But I still like the look of both. Is that wrong? There's a program called "Life After people" that shows how kudzu will take over... if left on it's own.

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  10. Invasive plants, animals, and insects can become quite an issue. That is a pretty one and the blackberries is a delicious one. I would think the bears and other wild critters would love those blackberries. :)

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  11. Yes those blackberies are yummy! Too cold for them here:)

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  12. How interesting! We don't have those plants being invasive here. Instead we have haole koa and the Mexican creeper vines.

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  13. Ivy can be very pretty, but invasive. Too much of a good thing, eh?

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  14. As you know, I'm dealing with quite a few invasive plants in my yard - including a blackberry bush! You truly do not want them anywhere near your yard/garden as they are near to impossible to eradicate. Most vines, however pretty, do have a tendency to take over everything. If one feels they MUST have one - put it in a pot to enjoy.

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  15. Got to watch out for those! We have our own share of invasive species here.

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  16. Eradicating English Ivy and Himalayan Blackberries are never ending struggles here. The ivy has to be cut, very hard work, and the blackberries get sprayed. Not so good either.

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  17. No kidding? An invasive plant with delicious berries. I don't see anything like that here. Then again, I'm not always sure what is actually an invasive species. I loved the scent of white ginger and then found out they are supposed to be an invasive species too. I could trade it for your blackberries though.

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