In one place in the yard, there is a carpet of ivy under a black walnut. Would it harm the tree in any way to let the ivy up to the base of the branches? I would like to do this so that the whole scene is green.

  • 2
    Remember that English Ivy is considered an invasive pest in large parts of the US - including, I believe PA.
    – winwaed
    Apr 3 '12 at 12:50
  • Okay so PA hasn't listed it as such, but a number of states with similar climates consider it to be an invasive. I would still be wary - just because it isn't a problem already doesn't mean you should help make it a problem!
    – winwaed
    Apr 4 '12 at 12:00
  • It doesn't do well on its own here. It needs weeding.
    – J. Musser
    Apr 4 '12 at 13:09

No, as long as it doesn't compete for light, the tree is healthy, and the soil situation is normal, ivy is fine on tree trunks. Ivy is not a parasite. Here's a good article.

The Alien Plant Working Group of the Plant Conservation Alliance lists English Ivy as invasive in many states, including PA.


Walnut and butternut trees try to ensure that there are no competitors for light and water by excreting a substance called juglone. It inhibits the growth of some plants. I cannot find ivy listed as being tolerant which would indicate that it's growth would be stunted.

You could try Virginia Creeper which is tolerant however a well established plant could compete with the walnut tree and inhibit it's growth.

With the price of black walnut wood you could be better off pruning it so it has a good form and then selling it when you want to retire.

  • 2
    I would vote "no" to Virginia Creeper, it can be VERY invasive and is hard to get rid of.
    – Shane
    Apr 3 '12 at 18:11
  • 2
    I agree that Virginia Creeper gets out of control easily. However it is native and in the shade of a mature tree could be manageable.
    – kevinskio
    Apr 3 '12 at 18:17
  • Virginia creeper is a weed around here. The Ivy is already growing under the tree, so I don't think it will be a problem.
    – J. Musser
    Apr 4 '12 at 13:13

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