Marga
Marga
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  • New York, NY
Asked on Jul 10, 2013

Gardening: Are black walnut trees toxic to other plants nearby?

Sue2102060MargaLouAnn Edel
+12

Answered

We sadly lost a bunch of trees in our little park from Hurricane Irene and Sandy, and were given a black walnut tree as a gift. I've heard these trees can poison their nearby neighbors such as blueberry bushes, lindens and crabapples. We really love the person who gave us the seeds, but maybe it's not quite the blessing we thought. Our space is small and the trees would be next to each other. Anyone ever had success with growing fruit trees nearby? We also have a willow in the area where we want to plant the walnut.
black walnut tree grown from seed. Where to plant?
black walnut tree grown from seed. Where to plant?
15 answers
  • Larose LoganOakes
    on Jul 10, 2013

    We have an Oak tree and then a Dogwood tree(both to the left of the small pond in the middle) and a small pond in the middle and then another Dogwood tree and then a Hickory nut tree to the right of the small pond.Does that make any sense? The leaves on the Dogwood tree that is next to the Hickory Nut tree shrivel up or curl up in response to the Hickory Nut tree.It looks so sad! The Dogwood that is next to the Oak tree is fine.We have lived here for 23 years and the Hickory and Oak trees were here when we moved in but we planted the Dogwoods shortly after we moved in as a birthday present for me one year.The one Dogwood tree is definitely affected by the Hickory Nut tree but it is surviving.I do believe that trees can put out toxins that can harm their neighbors. I used to have a book about that long ago but I can't remember the name of it.I hope this answers your question. Good Luck!:)

  • Patricia Brining
    on Jul 10, 2013

    I have never heard of that if that is the case then it should kill the grass that grows around it!

  • Christa L
    on Jul 10, 2013

    Walnuts (and pecans) produce a toxin which affects the respiratory systems of certain plants. It is called JUGLAN and is produced in the roots, but present in all parts of the tree. It persists in the soil for up to 20 years AFTER the tree has died. Walnut leaves should not be used to compost susceptible plants. Walnut chips should not be used within 40' of susceptible plants. Susceptible plants include tomatoes, peppers, eggplants, apple trees, rhubarb, bleeding hearts. Juglan-tolerant species include melons, raspberries, cherries, plums, beans, beets, daylillies, hosta and strawberries. Check with any agricultural college in your zone for more. Personally, I find the nuts to be a hazard underfoot and curing them is time-consuming and complex. If black walnuts are native to your area, I suggest you ask your local forest preserve if they would like to accept your seedling. Many other plants produce chemicals to suppress competition from other plants as well as to discourage nibbling.

  • Douglas Hunt
    on Jul 10, 2013

    Christa's advice is spot-on.

  • Peg
    on Jul 10, 2013

    Every part of the black walnut is toxic to many plants that cannot tolerate or survive the "juglone". It stays in the soil for decades, it odes not wash out or leach out of the soil. I learned the hard way after buying this "fixer-upper" of a property. If I could, I would cut down every one of them. Besides being toxic, they are messy. The nuts and stems mess up the yard. I had to make a raised vegies garden bed, a very high one so I can grow tomatoes, peppers, potatoes, things from the nightshade group because they will not grow in the toxic soil. There are no pines growing in the back where most of the b.walnuts are. None of the azaleas or rhodos survived, a waste of money and landscaping. My Mother's Day apple tree gift did not survive. I was flooded with plants as house warming gifts when I moved here, it broke my heart to loose so many of them. So, I had to do research to plant things that are tolerant of juglone.

  • Marga
    on Jul 10, 2013

    Thanks everybody! Guess I have to find a place to plant that bad boy all by himself, or with other black walnuts. I'm not taking the risk with the other plants nearby.

  • Dawn Neamon Enochs
    on Jul 11, 2013

    Our property came with a couple mature Black Walnut trees. They now pop up everywhere around the pond every year! Squirrels & Birds love the trees for hiding.

  • Peg
    on Jul 11, 2013

    Marga - I was flooded out by Hurricane Irene. I put up a few pics on here recently. My black walnut are so big, nothing would take them away or down!!

    , That was my back yard early in the day taken from an upstairs window Just the top of the trees are above the water All of my flower gardens are aquatic there LOL
  • Marga
    on Jul 11, 2013

    I love the fact that they produce nuts for the squirrels, and shade for us! Their wood is great for lumber, but we are a small space and I'm pretty sure they take over our garden. Now I need to find a new home for it. Maybe a vacant lot!

  • Virginia A
    on Jul 11, 2013

    yes, they are. Don't plant a vegetable garden near a black walnut tree. Nothing will do well.

  • Nancy Hatcher
    on Jul 11, 2013

    When we built our home in the woods I had never heard of juglone or allopathic effects. For the first 5 years I thought my green thumb had turned black. It was only by accident that I learned about black walnuts when I kept loosing my azaleas, blueberries, tomatoes and potatoes. There are many plants that are compatible. Veggies - green beans, beets, carrots, sweet corn, melons, onions, parsnips & squash. Fruits - peach, nectarine, cherry, plum, wild grapes, black raspberries and blackberries. Hostas, hollyhock, columbine, astilbe, clematis, delphiniums, ginger, mums, common daylilies, coral bells, crocus, most grasses, Siberian iris, Virginia bluebells are among the many flowers that are compatible with walnut. Not only does the juglone stay in the ground for 20 years but it also effects incompatible plants 50-60ft away. You can find a lot of information on the internet about compatibility charts although some information is contradictory. Other varieties of walnut also have juglone but the black walnut is the strongest. Good Luck!

  • LouAnn Edel
    on Jul 11, 2013

    If I were you I would definitely take that Black Walnut and find a home for it elsewhere. We bought our house about 20 yrs ago and have two of those bad boys...one at the front of the property and one at the back. This year they have really tried our patience as we have seedlings popping up all over the place, from the squirrels carrying off the nuts and stashing them. They are coming up in most, if not all, of my flower beds, up against our outbuildings...they seem to be everywhere I look. We're getting our fill of trying to get rid of those seedlings as well as the nuts we find on the ground as fast as we can...AND needless to say the 2 main trees WILL BE CUT DOWN the first chance we get.

  • Marga
    on Jul 12, 2013

    @Larose D. Logan-Oakes - Wow.. that link you posted states that the juglone substance even attacks soil planted in raised beds.. @Peg - I love how these trees are so resilient. But again, I am a community gardener in NYC and our space is too limited for such a powerhouse. Anyone want a black walnut? I've got one for you!!

  • Sue2102060
    on Aug 17, 2015

    Does the juglone from Black Walnut trees effect bird baths when the tree's leaves fall in the water?

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