Black Walnut and the effects of juglone

Asked June 23, 2018, 5:06 PM EDT

We chose a lot and built our house in 1983. There were 2 large black walnut trees close to one side of the property and 2 others were growing even closer, one of which we had felled but not because it was a black walnut. Too late to prevent damage, but the other we allowed to grow. I was raised in England and did not know the effect these trees could have on plant life. I am wondering if there is a test to discover if the soil has recovered. I was once told it would recover in 5 years but that is way out. My vegetable garden is a waste land. A wonderful rose plant was destroyed about 20 years ago and I have just noticed a replacement rose I planted about 5 years ago and has barely survived until now has shown strong signs of improvement this year. I wonder if it could be a positive sign the juglone has seeped away.. Brian Burton. London, Ontario, Canada.

Outside United States black walnut tree horticulture

1 Response

Thank you for your question, Brian. Here is an article on the topic: http://www.omafra.gov.on.ca/english/crops/facts/info_walnut_toxicity.htm Several other Experts have searched for labs that test for juglone, and have been unsuccessful. I suggest you contact your government to inquire about their availability there. I suspect that results will vary from one part of the yard to another, which is why avoiding susceptible plants, and using container gardens is the smarter ‘cure.’ Hope this is helpful. Good luck!