365 Urban species. #362: English Ivy

[urbpan]

Photos by cottonmanifesto. This planting in Boston's Longwood Medical area has succumbed to its ground cover of ivy, spilling over the edges of its planter.

Urban species #362: English Ivy Hedera helix

While holly has become a symbol tied to a certain holiday, ivy is symbolic of eternal life and fidelity, but is not necessarily associated with Christmas. It clings year-round to the trunks of trees, providing dark green leaves after the tree's own have yellowed and fallen. Even long dead trees standing bare are given the appearance of life with a coating of ivy vines. However the ivy itself may contribute to the demise of the tree it adheres to. Its weight makes the tree more susceptible to storm and ice damage, and the ivy's foliage eventually covers the tree's own, stealing the sunlight.

English ivy is thought to be originally native to central Eurasia, but its attractiveness has encouraged humans to bring it to North and South America, Australia and New Zealand, and many other places. There are hundreds of cultivated varieties available as houseplants, ground cover, and even shrubs and small trees. Ivy takes a decade or more to mature--most urban plantings are a juvenile phase of the plant. It's only when ivy is able to climb a tree or other object that it's able to change into the mature phase and bear flowers and fruit. Ivy is popular as a ground cover because it covers so thoroughly, and its toxic vegetation is resistant to the attentions of rabbits and deer.

Its ability to grow in deep shade makes its presence troubling to woodland stewards. In a forest, ivy may completely overwhelm the habitat, creating what has come to be called an "ivy desert." In the Pacific Northwest a war is being waged against English ivy. In the city of Portland, a group called the No Ivy League has formed to tackle its invasion of Forest Park, the largest urban forest in the country. They attack it by pulling and clipping, but also by encouraging students and researchers to learn more about the plant. For example, its widely thought that birds eat ivy fruit and spread the seeds, but there also seems to be evidence that the fruit is toxic to native North American songbirds. The North American pollinator is likewise unknown. The League also works to educate the public about the ecological danger of ivy, and helped to get the plant listed as a noxious weed by the Oregon Department of Agriculture.


English ivy battles with pachysandra for the habitat of this parking lot planter.

Comments

[sin-agua.livejournal.com]

So, it's like the English kudzu?

Spend a good portion of yesterday trimming this stuff back and tearing it off plaster walls of the admin building. Didn't know that bit about it not flowering or whatever unless it's growing on something upright. Interesting!

[urbpan.livejournal.com]

Pretty much. Kudzu, as I understand it, grows much faster, and can bring down trees with its sheer weight. It does have the advantage of being edible, however.

[bellisaurius.livejournal.com]

Well, that sort of ruins my idea for greening up the city. Here was my thoughts:

Greenery/Plant life is a function of available surface area (As opposed to just two dimensional ground area). The most easily accessible surface area in a city is the sides of buildings. As ivy is one of the species that can grow on buildings, we should encourage such growth since it should have several possible benefits: Creating a dead air zone around a house, acting as cover to keep a house cool, as well as preventing the stones from picking up heat, thus minimizing the urban heat island effect.

[urbpan.livejournal.com]

I like that idea, too. Ivy also has the unfortunate consequence of destroying masonry, so another plant would definintely be a better choice. In the northeast, maybe Virginia creeper? My building used to be covered with Boston ivy but it was all removed. Our apartment was much cooler in the summer when it was there.

Everything in moderation

[(Anonymous)]

Although this plant may be awful looking and spreads like wild fire in the garden, it's actually a very good house plant. The English Ivy can eliminate household toxins, particularly formaldehyde, which is a cancer causing substance that can be found in not only in personal care products but also in no-iron clothes;drape and fabrics;insulation materials, plywood, and particleboard used to build homes; paints; and especially medium density fiberboard, which is used to make furniture and cabinets.
So, please don't eliminate it completely just because it doesn't belong in the garden!

English Ivy?

[(Anonymous)]

Hi, I am trying to find out if English Ivy can be eaten. You say that it can. Have you eaten any?. I know that there is a ground ivy that is edible but that won't be up until the fall one of my sources says. Because ground Ivy is so good for a person I am wondering if I can substitue it with English Ivy. I wouldn't mind hearing from you on this one. Sincerely E. Valentine

Re: English Ivy?

[urbpan.livejournal.com]

I did not say that it is edible. I said it was toxic. Those are opposites. Ground ivy and English ivy are not closely related; do not substitute English ivy for ground ivy.