You will be fine as long as you don't plant under them and keep away 60 feet. [SIZE=10.5pt]Black walnut trees, Juglans nigra, are notorious for killing off gardens. These trees produce a toxic substance called juglone, present in all parts of the tree. This toxic substance causes plants to shrivel, turn yellow and eventually die. The zone of toxicity for black walnut trees can be as great as 80 feet, seeming to ruling out the possibility of a garden for some homeowners  with black walnut trees on their properties. It is entirely possible to grow a garden beneath a black walnut tree if proper care is taken to reduce contact with all parts of the tree, including the roots and the correct plants for the site are chosen.[/SIZE]
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[SIZE=10.5pt]To determine where not to put plants that may be sensitive to the toxicity of your black walnut tree, assume a 60 to 80 foot radius from the trunk of your mature tree. Young trees up to 8 feet tall have a root radius of twice the height of the tree. The toxic radius grows as the tree grows. Even some plants that are reportedly resistant to the effects of juglone cannot be planted too close to your black walnut tree. If you remove your black walnut tree, the remaining roots will keep the ground toxic for some time afterward. Similarly, if you use mulch made from the bark of a black walnut tree, allow it to compost for 6 months before using it on plants sensitive to juglone.[/SIZE]
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[SIZE=10.5pt]Several plants are known to be sensitive to the toxicity of your black walnut tree and should not be planted under or near it. These plants include columbine, asparagus, lilies, alfalfa, rhubarb, silver maples, white birches, apples, crabapples, Norway spruces, several pines, lilacs, yews, blueberries, blackberries, honeysuckle, rhododendrons and azaleas. Vegetables that will suffer under a black walnut tree include cabbage, peppers, tomatoes, eggplant and potatoes.[/SIZE]
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