I planted three frost proof gardenias about a month ago and have noticed that the leaves are yellowing with a few having dropped off. Although not under the canopy of the black walnut tree, they are within its root system. Are gardenias sensitive to the toxicity produced by these trees?
Gardenias and Black Walnut Tree Toxicity
Certified GKH Gardening Expert
Since Gardenias are known to be finicky, the Black Walnut Trees likely have nothing to do with the yellowing leaves.
Gardenias are not on the list of plants sensitive to juglone.
Yellowing leaves are likely related to watering issues or nutrient problems.
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