42 Plants That Die Near Black Walnut Trees / Juglone


It has been well documented for centuries that some plants either struggle to grow near Black Walnut Trees, or are outright poisoned by them [1]. Knowing what plants will struggle near Black Walnut Trees is important so you don’t spend money landscaping with them, or waste time growing certain vegetables [2], only to have them perish [4], [5].

Based on dozens of Journal Articles and University Ag Extensions, I’ve compiled a comprehensive list of 42 flowers, trees, and vegetables that can’t grow near a Black Walnut Tree. They will struggle to grow, or die if planted within 20-25′ of the dripline of a Black Walnut Tree.

Why Does the Black Walnut Tree kill other plants?

The Black Walnut Tree secretes a chemical from it’s roots, fallen leaves, and husk of the black walnut known as Juglone. This chemical gives the Black Walnut Tree (Juglans nigra) an allelopathic effect [3], killing certain plants that are within it’s canopy [5].

What is Allelopathy?

Allelopathy is where a plant secretes a chemical that will inhibit the growth of surrounding plants. Allelopathy is a neat evolutionary characteristic that some plants use to reduce competition. Think about it, if a tree can kill all surrounding plants, then it gets all the sunlight and soil nutrients.

As with any evolutionary process, some plants have been documented to be tolerant of Juglone. These plants can grow near, or within the canopy of a Black Walnut Tree. You may be interested to read the 201 different species of plants that are Juglone tolerant, and can grow near Black Walnut Trees.

Vegetables, Flowers, and Trees that Should NOT be planted near Black Walnut Trees!

NumberPlant TypeCommon NameScientific Name
1VegetablesAsparagusAsparagus officinalis
2VegetablesCabbageBrassica spp
3VegetablesCucumbersCucumis sativus
4VegetablesEggplantSolanum melongena
5VegetablesPeppersCapsicum spp
6VegetablesPotatoSolanum spp
7VegetablesThymeThymus vulgaris
8VegetablesTomatoes [2]Solanum spp
9FlowerBlue False IndigoBaptisia spp
10FlowerButtercupRanunculus
11FlowerChrysanthumumChrysanthumum spp
12FlowerColumbineAquilegia spp
13FlowerFlowering TobaccoNicotiana alata
14FlowerForget-me-notMyosotis
15FlowerHydrangeaHydrangea  spp
16FlowerLiliesLilium
17FlowerLily of the valleyConvallaria majalis
18FlowerPeoniesPaeonia
19FlowerPetuniaPetunia spp
20FlowerRhubarbRheum rhabarbarum
21FlowerCrimson CloverTrifolium incarnatum
22Shrub / VineBlueberryAsparagus officinalis
23Shrub / VineBlack BerryBrassica spp
24Shrub / VineMountain LaurelCucumis sativus
25Shrub / VineGrapesSolanum melongena
26Shrub / VineAmur HoneysuckleLonicera maackii
27TreeApple TreesMalus spp
28TreeBasswoodTilia spp
29TreeBlack AlderAlnus glutinosa
30TreeCottonwoodPopulus
31TreeCrabapple TreesMalus
32TreeCypressCupressus
33TreeEastern White PinePinus strobus
34TreeHackberryCeltis occidentalis
35TreeMagnoliaMagnolia grandiflora
36TreeMugo PinePinus mugo
37TreeNorway SprucePicea abies
38TreeRed PinePinus resinosa
39TreeScots PinePinus sylvestris
40TreeSilver MapleAcer saccharinum
41TreeWhite BirchesBetula papyrifera
42TreeRussian OliveElaegnus angustifolia

How long does Juglone poison stay in the soil after cutting down a Black Walnut Tree?

So, if you remove a Black Walnut Tree and want to start a garden, fear not! There are certain bacteria that can feed solely on Juglone [6], which is likely a large component of the variation.  So, the bacteria known as Pseudomonas putida J1 was found to to break down Juglone rapidly if soil was aerated.

So, if you cut down a Black Walnut Tree in your yard, you will likely be able to begin planting flowers / trees / shrubs after removing a tree. It will just take some time for the bacteria to break down the Juglone in the soil.

Learn More About Black Walnut Trees

References:

[1] – Pliny the Elder, AD23-79. https://extension.illinois.edu/blogs/garden-scoop/2018-08-23-black-walnut

[2] – I. Kocacë Aliskan & I. Terzi (2001) Allelopathic effects of walnut leaf extracts and juglone on seed germination and seedling growth, The Journal of Horticultural Science and Biotechnology, 76:4, 436-440, DOI: 10.1080/14620316.2001.11511390

[3] – J. Chem. Educ. 1973, 50, 11, 782. Publication Date:November 1, 1973. https://doi.org/10.1021/ed050p782

[4] – Dana, M. & Lerner, B. Black walnut toxicity. Purdue Univ. Coop. Ext. Serv. HO-193-W, 2 (2001).

[5] – Brown, Diane. Growing vegetable gardens near black walnut trees. Michigan State University Extension. Retrieved 29OCT2020.

[6] – Schmidt SK. Degradation of juglone by soil bacteria. J Chem Ecol. 1988 Jul;14(7):1561-71. doi: 10.1007/BF01012522. PMID: 24276429.

Joe Foster

Hi - I grew up outdoors in nature - hiking, fishing, hunting. In high school I got my first job at a garden center where I learned to garden and landscape. I've been growing plants from seed and designing native plant gardens for over six years. I hope to share some of my knowledge with you! Additionally I am a wood worker / DIY enthusiast. I enjoy designing/building projects (with hand tools when I can!). I hope to give you some tips and useful information!

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