We Plant Under Black Walnut Trees: Busting the Myth Once and For All
If you've ever walked away from a patch of beautiful land because there was a Black Walnut tree nearby, you're not alone. We recently had someone inquire about our Crop Collective who explained they don't have much room because they are surrounded by black walnut trees and so they have to use raised beds. We smiled because every single one of our gardens is under or adjacent to massive Black Walnut trees.
The lore runs deep: "You can't grow anything under Black Walnuts." Garden forums repeat it. Older gardening books declare it. Even some extension services keep the warning alive.
But here's the truth: it's not as simple, or as hopeless, as they make it sound. In fact, with the right knowledge and a bit of patience, you can absolutely have a thriving, diverse garden beneath or near Black Walnut trees.
Let's dig into the myth, the misunderstood science, and how you can confidently plant around these majestic (and misunderstood) trees.
The Root of the Myth: What Is Juglone, Really?
Black Walnut trees (Juglans nigra) naturally produce a compound called juglone. It's found in their leaves, bark, nuts, and roots. Juglone is categorized as allelopathic, meaning it can affect the growth of other plants nearby. In the case of Black Walnuts, it's part of a survival strategy: slow down the competition for nutrients and water in the immediate vicinity.
But here's where things go sideways. The assumption has long been that juglone is universally toxic, and therefore nothing can grow near these trees. This idea has taken hold without much challenge for decades.
In reality, juglone isn't some indiscriminate, plant-killing chemical. Its impact is highly variable and depends on a number of factors, including:
Soil type and drainage
Microbial activity (especially in healthy, organic-rich soils)
Consistent moisture levels
Proximity to the tree's roots
The species and resilience of the neighboring plants
What's more, many older studies that led to juglone's bad reputation were conducted in artificial environments with juglone extracted in high concentrations, which is not what you'd find in the average garden soil.
In healthy, living soil with good water flow and microbial life, juglone breaks down relatively quickly. Unless you're planting right up against the tree's trunk, your plants have a fighting chance, and many don't just survive, they thrive.
The Overlooked Fact: Many Plants Don't Mind Juglone
Let's set the record straight: not all plants are sensitive to juglone. In fact, many species, especially those native to the eastern U.S. or considered hardy, don't show negative effects at all. Gardeners who've worked near Black Walnuts for years have shared long lists of plants that do perfectly fine, even directly beneath the canopy.
Here's a breakdown of what you can plant with confidence:
Vegetables That Can Tolerate Black Walnuts
The following list is based not only on what peer reviewed and reputable sources state on the Internet. We've tried all of these. Most are growing in our garden beds right now directly under the canopy of one 40 foot Black Walnut Tree and not less than 20 feet from another over 60 foot Black Walnut Tree.
Squash (zucchini, acorn, etc.)
Cucumber
Beans (bush beans, pole beans)
Soybean
Corn
Beets
Radish
Potatoes
Carrots
Parsnips
Onions
Garlic
Leeks
Peas
Lettuce
Arugula
Dill and parsley
Most root vegetables and members of the onion family have little to no sensitivity to juglone, especially if you keep the soil moist and enriched with compost.
Perennials and Flowers That Thrive Near Juglone
Daylilies
Black-eyed Susan
Bee balm (Monarda)
Daffodils and snowdrops
Yarrow
Coral bells (Heuchera)
Hosta (surprisingly resilient when well-watered)
Astilbe
Phlox
Zinnia
Marigolds
Blue Cornflower
These beauties don't just survive. They can form vibrant understory displays that give you color throughout the seasons.
Moisture, Mulch, and Microbes: Your Three Garden Allies
If you're still hesitant, here's your secret weapon: water and organic matter. Juglone's impact is most severe in dry, compacted, or nutrient-poor soils. But in well-watered, organically rich environments, it breaks down quickly, especially with microbial help.
We live in West Virginia, and with the exception of drought seasons, we get a lot of rain. Combine that with the fact that our entire property is on a hill, drainage is not a problem for us. But when it's hot and dry, we know we have to drag hoses and ensure our gardens are watered.
Here are some tips for creating the best conditions under a walnut tree:
Water deeply and regularly unless you get heavy rains. Moisture helps dilute juglone and promotes the microbial activity that breaks it down.
Mulch generously with compost or wood chips. Organic mulch feeds soil life, maintains moisture, and acts as a buffer.
Avoid disturbing the tree's root zone too much. Digging too close to the trunk can damage the tree and stir up higher juglone levels. If possible, work around the outer canopy instead.
Pick the vegetables and flowers that aren't impacted, and experiment with the ones that may be.
Busting the Fear: A Fresh Perspective
Black Walnut trees are powerful, beautiful, and ecologically important. They provide food and shelter for wildlife, dense shade in the summer, and rich fall color. It's a shame so many have been removed or avoided based on outdated gardening fear. We love ours and would be devastated to lose them.
Yes, juglone exists. But it's not the gardening death sentence it's made out to be. Like most things in nature, it's a complex process, not a hard rule. And with the right plant choices, water, and soil care, you can grow more than you ever thought possible under that walnut tree in your yard.
Instead of giving up on gardening near a Black Walnut, take it as an invitation to garden smarter, and don't accept every rule as absolute until you've tested it yourself.
Have a walnut in your yard and want to test what works? Start with a small bed or just plant without clearing and try out some veggies like beans and peas, and observe. You might just discover that not all gardening rules are law, and a lot are making us waste space.