7

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.

J. Musser
  • 51,627
  • 21
  • 115
  • 320
  • 2
    Remember that English Ivy is considered an invasive pest in large parts of the US - including, I believe PA. – winwaed Apr 03 '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 04 '12 at 12:00
  • It doesn't do well on its own here. It needs weeding. – J. Musser Apr 04 '12 at 13:09

2 Answers2

10

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.

Ed Staub
  • 6,389
  • 25
  • 31
4

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.

kevinskio
  • 57,927
  • 9
  • 76
  • 157
  • 2
    I would vote "no" to Virginia Creeper, it can be VERY invasive and is hard to get rid of. – Shane Apr 03 '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 03 '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 04 '12 at 13:13