We have lived on our 0.7 acre suburban lot in Camas, WA since 1990. Two years ago I found an English Ivy sprout in our yard, the first one I have ever found (after living there 20 years). Lately I am finding more and more sprouts, e.g. this weekend I pulled around 20. English ivy is not present in our immediate neighborhood, but there is some about 3/4 mile away, and there are larger patches beyond that, which have been there ever since we have lived here.
I definitely do not want this plant in my yard. I am trying to figure out what has changed that is causing it to show up? Is my yard now attracting some bird that was not around before? Is there some new patch in one of my neighbor's yards? If that were the case I think I would see it, since in order to be spread by birds (which I believe is what is happening), the ivy has to produce seeds, and in order to do that it has to grow up high (tree, wall, pole, etc.) and is thus more visible. But I have not seen it in any new places.
The only thing I can think of is that more starlings may be coming to our yard because 1) I have been putting out more suet than I used to (not for the starlings, for native birds, but some of the starlings have figured out how to get to it) and 2) our trees are getting fairly large and thus more birds stop in them. I have noticed that most of the sprouts are under trees. Although there were a bunch of them where a robin hung out for a couple of weeks while he had an ongoing battle with his reflection in one of our basement windows. So maybe robins are delivering the seeds?
I'm hoping that someone who knows more about birds and ivy can chime in here. It would make sense that starlings like ivy since they are both native to the UK. But I'm not sure about robins. And maybe there is some other cause. But it makes me really nervous because once ivy takes hold it is pretty tough to get rid of. I will stay on top of it, but I doubt that my neighbors will which means I will be fighting it even more.
I have found orange surveyor's tape useful. After clearing an area, mark it with tape so that you can easily check on re growth. You might have to pull it 5 times to kill it. For years I have kept ivy out of the trees on a 1 km stretch of ocean side park.
flowers in fall, matures berries in spring. that unusual timing means that a lot of critters love ivy. it's a great nectar source for all sorts of bugs when there isn't much else flowering, and it's a great source of fruit quite a bit earlier than just about anything else. I've seen quite a variety of birds eating ivy berries, including cedar waxwings.
my personal approach to ivy is to leave the mature plants that are growing on snags, because I value the nectar for my honeybees. when I see it growing elsewhere, I cut it up. it doesn't seem to be spreading at our place in the last ten years or so that I've been paying attention.
it's also valuable for growing on and protecting masonry walls.
but that's not what you're interested in. many bird species eat ivy berries. some birds cover a fairly large territory, so it isn't necessarily coming from real close by. maybe the dirt in your yard is in better shape now, and more likely to germinate the seeds. unless you can completely fill the niche ivy wants with something else, my guess is that it's going to be one of those things you'll just have to keep an eye on. roguing out little seedlings is certainly easier than removing large established vines.
I think Tel makes good points about its unusual seasons usefulness, I've observed the same things here. Plus I have dairy goats so its valuable late winter early spring green browse for us and I make a big dent in all of it near me. Its about the only berry-ish fruit that they eat for some reason, so we do make a big impact on reducing its spread here locally.
My suspicion after observing local ivy for many years, is that some patch you don't know about in someone's nearby yard or inaccessible area, has matured to start producing the fruit. I've seen big changes when that happens.
We don't have time for this. We've gotta save the moon! Or check this out: