Black Walnut, Junglans nigra, and its close relative, the Butternut, Junglans cinerea, produce juglone which is toxic to many plants.

Image by Mabel Amber from Pixabay 

  • Keep sensitive plants at least 20 feet away from these trees.
  • Many plant species will not die immediately but slowly over a period of years.
  • Other species, particularly those in the Nightshade Solanacea family, are extremely sensitive to juglone and will decline much quicker.
  • Removing the offending tree will not solve the problem, since juglone is contained in all parts of the root system, and unless every piece of root is removed plants in contact with the roots will continue to suffer the toxic side effects for many years.

Rue Anemone – MN native wildflower

 

Perennials Resistant to Juglone

Adiantum pedantum (Maidenhair Fern)
Alchemilla (Lady’s Mantle)
Anemonella thalictroides also known as Thalictrum thalictroides (Rue Anemone)
Aquilegia (Columbine)
Asarum canadense (Wild Ginger)
Asarum europaeum (European Ginger)
Astilbe (Astilbe)
Athyrium niponicum (Japanese Painted Fern)
Bergenia (Pigsqueak)
Brunnera (False Forget-Me-Not or Siberian Bugloss)
Epimedium (Barrenwort or Fairy Wings)
Euonymous fortune (Winter Creeper)
Filipendula rubra (Queen of the Prairie)

Heuchera ‘Cajun Fire’

 

Heuchera (Coralbells)
Hosta (Hosta)
Ligularia (Groundsel or Ragwort)
Matteuccia struthiopteris (Ostrich Fern)
Polygonatum odoratum (Solomon Seal)
Primula sieboldii (Primrose)
Pulmonaria (Lungwort)
Tiarella (Foam Flower)
Tricyrtis hirta (Toadlily)

Hosta ‘Afterglow’

 

Other Plants Resistant to Juglone

Crataegus (Hawthorn)
Malus (Crabapple)
Poa (Kentucky Bluegrass)
Prunus (Cherry)
Robinia (Locust)
Rubus (Black Raspberry)
Trifolium (Clover)
Ulmus (Elm)
Vitis (Wild Grape)

‘Royal Raindrops’.

 

Plants Susceptible to Juglone

Vegetable Plants including: Beans, Cucumbers, Eggplant, Green Pepper, Potato and Tomato

Betula (Birch)
Celtis (Hackberry)
Cotoneaster (Cotoneaster)
Medicago (Alfalfa)
Tilia (Linden, Basswood)
Vitis (Domestic Grapes)

The experts at Gertens are always available to answer your questions!