First, English ivy will grow where IT wants to, not necessarily where you want it to. Second, I would not suggest planting it on a wooden structure. As it is evergreen, it will retain moisture under the foliage (prevents the sun hitting it and evaporation) and this constantly moist situation will promote rot. Third, it is a very desirable hiding/housing environment for rodents. Fourth, ivy that is trained or encouraged to grow upwards will more readily develop into the adult stage and flower and set fruit - a very dangerous condition. And this is all in addition to its rabidly invasive characteristics :-)

Not a plant I'd suggest anyone, in any location, plant intentionally.

Knowing what I do now, I wouldn't do it. It's a beast. It will spread by underground runners, popping up clear across the yard, going up trees, fences, EVERYTHING.

I had wanted some to go up a brick facing on our house. Our neighbor has tons of it and it looks fantastic. She was collecting different types, even has some from Mt. Vernon, George Washington's home. So I went over to discuss it with her (okay, I was hoping for cuttings! LOL) and what she said was: "ARE YOU OUT OF YOUR MIND? Look at this! DON'T DO IT! I am soooo sorry I planted this stuff!" She scared me, and I didn't do it!

In our state, WA, it's on the noxious weed list now. I HATE the stuff and everyone in our neighborhood has been pulling it up and getting rid of it in the past few years. Our neighbor planted some on an embankment between our houses, and I have to cut it back 3 times a year because it grows into my garden.

I'm trying to find a diplomatic way to suggest getting rid of it and planting some other ground cover :)

And speaking of rodents, my Jack Russell Terrier has had many fun times rooting out and killing small rodents that live in the ivy patch.

Well, I think it's a function of what you're trying to do with it, where you're planting it, and what zone you're in. I would NOT try to use it as a groundcover in or near a perennial garden - it does tend to spread and if it gets itself all tangled up with other plants, it will be hard to get it detangled.

And, you certainly could plant it so that it climbs a wooden structure, but it is true that it will retain moisture, and the structure, unless it's very thick and sturdy, may rot sooner than it would otherwise. As for providing cover for rodents, well, I'm on wooded lot, and we are overrun with squirrels, and chipmunks, and God knows what else out there, and frankly, I'm convinced beyond doubt that they'd be there whether I had ivy in my yard or not!

All of that said, I have it in several places in my yard, and I LOVE it where it's planted! One spot is on the ground around a huge old elm tree and on either side of a flagstone walk nearby. It's very thick, and it's climbing the trunk of the tree. Among the ivy, I have Celandine Poppies planted, and they seem to coexist very nicely and are very pretty together.

I know posters will flood this message board with alerts about the dangers of letting it climb the tree, but I have an arborist who helps us take care of it (it's about 100 years old, much taller than our two story house, and the trunk is so big that I can't get my arms around it). He checks the tree (and others on our wooded lot) every year for dutch elm disease, and prunes it so it doesn't send big dead branches slamming into the house when it storms. This guy loves tress and knows more about them than anybody I've ever met. He has assured us, a number of times, that the ivy WILL NOT harm the tree, as long as we don't let it get tangled up in the canopy of tree. Climbing the trunk, though, is fine.

It's very pretty. I do have to say that I keep it trimmed, so that it doesn't creep into my neighbor's yard, and so that it doesn't cover the flagstone walk, and I keep it away from the hostas I have planted nearby, but it's not at all hard to control.

The area is shaded, and we're in zone 5, but winter zaps it pretty severely most years, which I think helps to keep it controlled.

Would I recommend this plant to somebody else? Depends, like I said, on where you're planting it, what you're trying to accomplish with it, and whether you mind going out there a couple of times a months with a pruner. For the right person in the right spot, it could be a perfect choice!

One of the problems that has been hinted at but not explicitly stated: Birds eat the berries, and thus spread the seed all over the woods. The ivy runs rampant there and crowds out the native plants, rendering the area useless for a lot of our native fauna. Some of our natural areas are turning into "ivy deserts", devoid of the normal mixture of species. Please don't contribute to the problem!

I'm not sure that you will be successful at covering a wooden stockade fence with Ivy (Hedera sp.). Since it's only means of support are roots, formed at nodes along the vine, they must have a rough surface with cavities to penetrate, for support. It only climbs trees and shrubs that have rough bark and clings to walls, such as brick and stone, that have closely spaced masonary joints that the roots can penetrate. I planted one near my mailbox post(4x4 treated wood), thinking it would cover and hide the post. After more that 20 years, it has not been successful in climbing that post. It's still just a mounded plant about a foot high.
There are also different types of Hedera helix, some varieties, known as branching type, form offshoots at leaf nodes and can more rapidly cover an area. There are others, with thick woody stems, that grow upright and must be supported with wooden or metal stakes. These are not Adult Ivies and do not flower and produce berries.
As long as Hedera sp. of Ivy is grown in a shady location and not allowed to climb into an open sunny location, where it begins to flower and produce berries (Adult stage), it poses no environmental threat, except in your own garden, of course.
Responsible management can produce a desirable plant for ground cover, Topiaries, Hanging Baskets(alone or as a group planting) and potted accent plants.
I'm sure that climate can effect the dispersal of Hedera sp., but in my area, it is only a problem in Urban areas. As a Native Plant Society member, I have visited many woodland tracts in this state and have never found it growing in any of those.
Rb

Ah, yes, I thought I was reading the Northwestern Gardening forum when I posted my reply. I'll amend it to: Check to be sure it's not a problem in your area.

English ivy (Hedera helix and its 300 or so named cultivars) attaches itself by holdfasts, not roots. It does not require a rough surface but can attach and cling to both smooth stucco or concrete surfaces or to rougher wood or bark. These holdfasts appear anywhere along the stems the plant desires or requires. The development of the adult form does not necessarily require full sunlight - it only requires a certain degree of height, which encouraging it to grow up a wooden fence could certainly accomplish. Yes, it is true that its invasive properties are determined to a large degree by climate as is the case with most invasive species, but it is considered an invasive species/noxious weed in 18 states and the District of Columbia, and by the US Parks Department and the Forestry Service.

And the rodents that find it most appealing for cover and/or housing tend to be rats :-( And where there is any kind of human habitation, there are rats.