Pears and black walnut?

I have been reading all I can here, and don’t see my answer. How are OHxF87, OHxF97 rootstocks with black walnut trees? Juglone tolerant, or not? My googling has conflicting info about pears.
Specifically- I want to plant some pears near a mature (30+year) black walnut. Up a slope by 4 or 5 feet, about 35 feet or so at closest point. Do you think this will be an issue? I am going to behead and graft several callery-type pears that have not had an issue growing on a drainage swale with black walnut. If I need to, I’ll graft onto callery for the area near the walnut, but the other rootstock is on the way for the rest of the yard. And I was going to try growing some pears own-root, would like an idea if that will work in this area. Edited to add- they would be Seckel or HoneySweet, most likely, but I have other Euro pears to try.


I do not have a scientific answer for you, but I have a large pear near the drip line of a huge black walnut. You can tell the root spread of the walnut reaches out to the pear. The pear is very productive. Unknown rootstock. Can’t find a photo of the tree, but here is a photo of the pears.


The roots of that walnut extend well beyond the drip line. I have them here and have not seen any affect on anything. To be safe. When you dig if you hit any roots move away from them.

I lost two Kieffer pears on OHxF 87 to juglone years ago. I did lots of reading to try and figure out what is and what is not resistant to juglone. I don’t believe there is an “answer”. It will vary from site to site and soil type to soil type.

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Pawpaw, mulberry, and a few others are immune to it. Can’t be deadly to everything or there would be open circles around all of them everywhere.

Actually, there are open circles around many walnut trees. except for grass, raspberry briars and various shrubbery.

I’ll be just as curious if someone has definitive information pertaining to pears.

Apparently apples and serviceberries are somewhat affected by walnut, but it doesn’t always kill them from what I can tell.

I wrote an article for local weekly paper on the juglone issue some years back.

Some magnolias won’t live even 50 feet from a black walnut.
Golden rain tree, Norway spruce, red cedar (Juniperus Virgiana), pawpaw, persimmon, hackberry, American holly, privet hedges, sugar maples, daffodils, hellebores, tulips, daylilies, Asiatic lily, there are quite a lot of things that can be grown in proximity to a walnut.

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@BlueBerry I have always heard that it was the leaves and husks that actually put the most juglone in the ground and the roots were in smaller amounts. For me oak root rot fungus has been more of an issue than juglone.

Nope, walnut tree leaves in your compost pile won’t do nearly as much damage as planting in the root zone…even if the walnut tree has been cut down, the roots will carry the juglone for many years.
(Worse in clay than sand, though).

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Just thought about something. Most of my walnuts are heartnuts and they are said to have much less juglone. Which could be why my minimal problems. I can say 100% certainty sticker bushes are immune. Interested in any? Have plenty to spare.

That’s interesting…but ‘sticker bush’ doesn’t really help me understand what bush you’re referring to.
Wild raspberries thrive under black walnuts…and they definitely have thorns. Any other name for your sticker bushes?

No, just joking. Been trying to kill the sticker bushes for years now. Wild raspberries is another I am fighting a losing battle with. This could actually make a thread of its own. What fruits do you have growing near walnut?

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Some wild callery can adapt to black walnuts which remember are alleopathic. Like cedar we know black walnuts put out an effective poison for other plants. Wild callery can in some cases (they are all gentically unique) adapt to tolerate growing in the proximity of some alleopathic trees. In the woods multiflora rose, poison ivy, poison oak, wild grape, autumn olive, and others have some tolorance. What i would do in your situation is find a wild callery growing with black walnuts and dig it up and bring it home.

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OK- so that one is a no. I’ll try them farther than the callery roots to be safe.

I will do that- I am cutting a callery and topworking it, because it’s there. I have the OHxF87 on order, but I will cut root sprouts from the callery for anything close to the walnuts and property line.
I am putting elderberry, pawpaw, mulberry, willow and currant closer to the walnuts than where the apples are going. From what I understand that should slow any juglone transport as well.
Oh, and black raspberry, that pops up by itself there. I love them, now trellising what grows for more fruit.

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Technically if OHxF87 is not under patent you could graft it to wild callery as well. Im not sure legally what the rules are but physically im saying it could be done. Read more on interstems Interstem aka interstock Pear Grafting and Interstem questions for added compatability Incompatible grafts but stick with callery or bet for the roots

Not all maples can handle juglone. Nut Tree Culture in North America R.A. Jaynes edition has a picture of 3 maple trees planted at different distances from a walnut. The maples are stunted in proportion to how close they are to the walnut. The only thing I ever tell anyone is totally unaffected by walnut is blue grass. The stuff is symbiotic with walnut to such an extent that it is hard to find a walnut that does not have blue grass growing under it.

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Now that brings up some things to experiment with. I might make the wild tree a multi-variety. Still might be deer food, but then I’ll know.
When you interstem, some people do that as two year process, some all in one go- correct? I already plan to try rooting the cut-offs of the OHxF87, might end up with more rootstock.

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Here is an example of one of the interstem grafts i did here The pears you may not have heard of and should consider growing with photos
71D46CEA-45B6-4B48-B8AB-D96A0252660C 35E5ADCC-EE8D-43D6-936E-C5786D038276

Bluegrass, yes. Also tall fescue, orchard grass and red clover do ok.

And, maples are variable, but I would have no fear of sugar maple. and would also do a Japanese maple near a walnut.

At least some pears are tolerant, although maybe not 100% resistant to juglone.
Wild roses, rose of Sharon, black locust, mulberry, forsythia, hawthorns, redbud, persimmon, pawpaw…ok I think I am repeating my earlier post…but quite a few things do well near black walnuts.

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That looks great- how long an interstem do you use? I really need to get familiar with what a callery seedling looks like, can probably find more and faster than I will get suckers off my own tree.

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