THE DARK SIDE OF THE...BLACK WALNUT TREE

If you are familiar with the Black Walnut (Juglans nigra) or you have it in/in proximity of your garden you might have noticed how hard is to grow something underneath it! Let’s see why but first…

…let’s get to know it a little better before judging it.

The black walnut tree is native or North America and its nuts were ‘famous’ already long long time ago in fact the presence of walnut shells is very common in Native American archeological sites and they have been harvested for thousands of years.

In Pennsylvania, Pennsylvania German settlers would choose lands with abundance of this tree and that’s because the black walnut wood was preferred to make cabinets and furnitures. Also, they would plant walnut trees near their farms as there was a belief that they would attract lightnings sparing the house from being struck.

The black walnut is a beautiful tree for shade, especially in large gardens; with its 50 to 100 feet hight it projects a light shade to the ground creating a perfect environment for the plants underneath it….

…but only if these plants are able to embrace the black walnut dark side!

Yes! Black walnut can be a tough partner, in fact, it produces a compound called Juglone that will inhibit the growth of the majority of the plants. Juglone Is released from every part of the tree, although the roots, nuts, and the seeds are the most toxic. It’s not a serial killer instinct, it’s just survival!

Juglone symptoms on apple tree saplings

Juglone symptoms on apple tree saplings

So if your plants experience:

  • wilting

  • yellowing of leaves

  • slow growth

  • death

and they are close to a black walnut tree, well, that might be the Juglone effect and there is no cure for that. The best thing to do is stop planting the black walnut tree!

But there are plants that might be stronger than the black walnut!

Here just a few:

TREES:

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  • Some maples

  • Serviceberry

  • Birch

  • Redwood

  • American beech

  • Plum

  • Cherry

SHRUBS:

Spicebush ( Lindera spp. )

Spicebush (Lindera spp.)

  • Holly

  • Rhododendron

  • Black raspberry

  • Elderberry

  • Rose of Sharon

  • Spicebush

  • Viburnum

  • St. John’s Wort

  • Witch-hazel

  • Sumac

  • Juniper

  • Thuja

  • American hemlock

PERENNIALS:

Coneflower ( Echinacea spp. )

Coneflower (Echinacea spp.)

  • Yarrow

  • Bugleweed

  • Anemone

  • Astilbe

  • Lady fern

  • Coneflower

  • Geranium

  • Hosta

  • Iris

  • Lilyturf

  • Daffodils

  • Primroses

  • Lamb’s ear

  • Tulip

If you have a walnut tree in your garden don’t worry and don’t take it down. Be aware that there are numerous plants that will grow just fine around it and seek the help of an expert.

“ The best time to plant a tree was 20 years ago. The second best time is now.” (Chinese proverb)

Black Walnut tree ( Juglans nigra )

Black Walnut tree (Juglans nigra)