What to Plant Under Black Walnut Trees

Black walnut trees are known for their distinctive and valuable hardwood, which is highly sought after in the furniture industry. However, these trees are also notorious for their toxic qualities, which can make it difficult to grow other plants around them. The roots, leaves, and nuts of black walnut trees release a chemical called juglone, which is highly toxic to some plant species. If you want to plant under black walnut trees, you need to know which plants are compatible and which ones to avoid.

Plants to Avoid

If you want to plant under a black walnut tree, there are several plant species to avoid. These include:

Azalea

Rhododendron

Lilac

Holly

Hydrangea

Magnolia

Juniper

Yew

Tomato

These plants are highly susceptible to juglone toxicity and will likely wilt, yellow, and die if planted under a black walnut tree. Additionally, other plants in the rose family, such as apple and blackberry, may also be sensitive to juglone exposure.

Plants That Tolerate Juglone

While there are many plants that are sensitive to juglone, there are also several species that can tolerate the chemical and thrive under black walnut trees. These include:

Hosta

Daylily

Ferns

Bee balm

Columbine

Astilbe

Foxglove

Iris

These plants are generally hardy and can be planted safely under a black walnut tree. However, it's important to note that plants that tolerate juglone may still be affected by other factors, such as soil compaction, water availability, and competition with the tree roots.

Other Considerations

If you want to plant under a black walnut tree, there are several other considerations to keep in mind. First, it's important to choose plants that are appropriate for the light and moisture conditions in the area. Black walnut trees have dense foliage that can create deep shade, so it may be necessary to choose plants that can thrive in shade or partial shade. Additionally, the roots of black walnut trees can be extensive and compete with other plants for water and nutrients. To avoid this, it's best to choose plants that have shallow root systems or can tolerate competition.

Overall, planting under black walnut trees can be challenging, but it's not impossible. With careful selection of compatible plants, you can create a beautiful and diverse garden under the shade of these majestic trees.