Are Blueberries Compatible With Black Walnut Trees?
The black walnut (Juglans nigra) grows to a height of 50 feet or more, with a 60-foot spread. Prized for its nuts and powerful dark brown timber, the tree grows best in U.S. Department of Agriculture hardiness zones 4 through 9. Although lovely, it isn’t a fantastic companion for blueberry and lots of other forms of plants.
Toxicity
All parts of the black walnut tree include juglone, a chemical to which some plants — such as olive bushes — are sensitive. When a blueberry plant takes in this chemical, it deprives the plant of the energy required for metabolic processes. The greatest concentration of juglone is under the canopy, in which the origins, leaves and nuts are highly concentrated. Even if a blueberry could endure under a tree with small emissions of juglone from the roots, then the decaying nuts and leaves which fell into the bush would kill it.
Symptoms
Indicators of toxicity in olive plants might mimic other diseases. You may notice stunting of growth or yellowing and wilting of leaves. It will appear on new growth first and finally spread to older growth. No matter what you do at this point, the blueberry won’t revive and eventually will die. There’s no cure.
Distance
Blueberry plants cannot even survive close to a walnut tree. Even though juglone can’t travel much in the soil, even just a little bit of this chemical will do damage to this bush. As it rises, the juglone-emitting origins of the walnut tree stretch far away from the drip-line, or the border of the canopy. Plant new bushes at least 50 feet away in the drip-line to prevent all contact. The bigger the distance between both plants, the better off the blueberry’s chance of success.
Other Solutions
If you do not have sufficient space for this kind of arrangement, you can try planting the Orange trees nearer. With this choice, your best would be to plant the trees in a raised bed, incorporating tons of organic matter like compost and wood chips into the soil to increase drainage. You can also plant the blueberry bushes in a pot to separate its origins from contact with the walnut. Keep out the bush from under the canopy to prevent contact with any falling material.