Rhodos, kalmia and walnuts

tomtuxman(6bNY)March 24, 2010

My dear neighbor and I are planning to plant a mix of rhodos and kalmias along our common fence line. However, we observed that there is a walnut tree (likely a black walnut) only about 25 or 30 feet away from our intended site. Having read several threads on this forum about the incompatibility of rhodos and walnuts, maybe this is not such a good idea.

However, dear neighbor suggested she would like to get rid of the disreputable walnut anyway (nuts dented her car) and that might solve the problem.

Question #1: Will the offending substance in the walnut's roots survive the tree's demise? If so, what is a respectible mourning period?

Question #2: One of the older threads suggested creating a raised bed with landscape fabric underneath and mulching new plants in well. Has anyone had experience or knowledge of success with this approach?

P.S. I have a lilac growing not 15 feet from the despised walnut, and it does fine despite info that lilacs are also incompatible with walnuts.

Your advice much appreciated.

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rhodyman(SE PA, USDA Z6)

Removing the tree and then using a raised bed with landscape fabric and a layer of gavel under it will solve the problem. The poisoning comes from the walnut roots as well as the leaves, etc. If a root cuts through the roots of the lilac, the problem will eventually show up.

I had a walnut start growing near a rhododendron bed. It started killing off the rhododendron branches before I saw it. I killed the walnut by girdling it and dug down around the rhododendron beds with a grubbing hoe and removed all roots that were coming into the rhododendron bed. I was able to save the bed. The walnut took about 5 seasons to die, but it was depleting its roots while doing this.

Steve Henning

    Bookmark   March 25, 2010 at 3:39PM
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