Pears and black walnuts not getting along?

I planted a heartnut tree at the end of a row of magness pear trees 20 yrs ago.
They have grown.
The “Jewelbox “heartnut is grafted on black walnut root.and planted At least 20ft. From the Pears.
The heartnut is growing like gangbusters . Looks good.
The last few years I have noticed a decline in the pear trees starting with the one closest to the heartnut and moving down the pear row ( 16 ft apart ).
The over all health , production of the pears in direct proportion to how far from that walnut root.
The aledged effect of the walnut root , now extending 80+ ft from the heartnut tree. Even though the branches are only nearly touching the fist pear. ~ 20 ft branch spread on heartnut.
At this point I will remove the pear. And replace with something more tolerant. (Pawpaw ,persimmon, what else will work.?)
So that’s 20yrs. To cut down and start over.
Lesson learned,
Wish grandpa would have been there , and told me not to plant those so close together.
I knew better at the time , really.
They just looked so far apart as little trees.
I love black walnut trees, and usually try to leave them be.where they come up around the farm.
But have recently noticed the effects they have on neighbor’s.
Not only these pears, but also apple trees , asparagus.gardens, etc.
I believe I am seeing juglone toxicity "”way “” farther away from the many walnut trees here than I would have thought would have been a problem . Sometimes showing itself as a general unthriftyness , lack of productivity,
Need to get my ducks ( trees !) in a row , where they will play “nice” together.
Thinking Pawpaw and walnut play well together ?
What are your thoughts on which fruit trees play well with walnuts?

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Wow, that’s a long way to still be having such an effect. Are the pears downhill from the walnut? Maybe the runoff from around the walnut is affecting the other pear, it may be possible to divert and help the pears.

I would expect any of the juglans specie trees to be tolerant of black walnuts, since they all produce some amount of the same toxin.

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About that, hmm. I planted some Butternuts close to a mature Black Walnut 4 years ago. I don’t believe they’ve grown any appreciable amount in that time. They get plenty of sun and are in very rich soil. They leaf out every year and at least appear healthy. But are only maybe a couple of inches taller than when planted.

I also hope your slope theory holds true. I have some Apple trees within 20 to 30’ of the same Black Walnut, but quite a few feet higher thanks to the probably 30+ degree slope there.

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Supposedly, mulberry can be a very good buffer option between walnut and other intolerant plants.

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(“ supposedly “) ?
That would be good ,I have several grafted mullberry to plant.
Any firsthand accounts they do well in the long term. .?
Hate to lose another 20yrs at this point.:grinning:

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@Bigdoug03
Essentially planted across a slope , on the conture, Heartnut at the end of row.

I’ve seen it mentioned in several places. I don’t have experience with the effectiveness of mulberry as a buffer myself other than repeatedly chopping/mowing mulberry growing underneath walnuts.

Here are a couple pages that mentioned mulberry as a buffer.

John Gordon in his northern nut growing info also says persimmon can work well intercropped with walnut although I don’t know if they would act as a buffer for your pears. Mulberry might be the tougher “weed”.

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My understanding has been that pears and persimmon are tolerant of Juglone/black walnuts? And also mulberries.

Certainly black raspberries thrive under black walnuts. PawPaw seem ok in proximity to black walnut.

Apples and serviceberries don’t work too well, but at 80 feet I would expect it to be OK.

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