by Julie Martens
When I first saw my backyard I had my mind set on creating a large vegetable garden with room for raspberries. There was just one problem: An ancient butternut tree dominated the space. (It’s the big tree entering the photo from the left.)
The butternut tree’s cooling shade hid a terrible problem: juglone.
It’s tough to garden under black walnut trees and their cousin, the butternut. Both nut-bearing trees produce a chemical called juglone that stunts—and even kills—susceptible plants.
This chemical occurs throughout a black walnut or butternut tree but concentrates most strongly in roots. A tree’s roots extend far beyond the leaves, so I had juglone-infested soil in the sunny areas most ideal for growing vegetables.
Removing a black walnut or butternut tree doesn’t solve the problem because juglone remains toxic in tree roots left in soil. So if you want to garden under black walnut or butternut trees you either need to remove the tree and replace soil or build raised beds.
I chose to build raised beds, starting with a mixture of topsoil and mushroom compost.
I planned to create a series of raised beds with a grass path between, so I had the bulk delivery split into two piles.
I divided the two piles into five separate raised beds radiating from a central path. I also dug paths between each bed.
Besides beating juglone, raised beds offer other benefits:
- Soil warms quicker in spring, which means I can plant early, especially with cool-season crops.
- The beds provide excellent drainage for plants.
My raised beds lack a frame to hold soil in place. There’s enough clay content to bind the soil, so the beds remain intact.
My beds measure 12 inches tall from the path height. The funniest thing about these raised beds is their winter appearance.
Everyone says it looks I’m burying bodies in the backyard. I just laugh and tell them I’m successfully dodging juglone.
To discover more details about gardening under black walnut trees, visit http://learningstore.uwex.edu/assets/pdfs/A3182.pdf.
To learn which plants are susceptible to juglone, visit http://ohioline.osu.edu/hyg-fact/1000/1148.html.