Practical Permaculture – Planting Under Walnut Trees


“White Astilbe” – Highland Park – Pittsburgh, PA – I’m starting this post off with this photograph of White Astilbe… Tolerant of juglone…. Astilbe will brighten the area beneath any shade tree…

If you live east of the Mississippi River, then you have probably seen a Black Walnut tree at some point in your life. Juglans nigra is the tallest of all the Walnuts, it is not uncommon for a tree to reach 100′ into the sky. Walnut trees have compound leaves that are spaced alternately along the branch. Each leaf is divided into an odd number, from 7 to 23 small yellow-green leaflets. Walnuts are monoecious, male flowers are long, unbranched, drooping catkins and the female flowers are single or short spikes. The fruit is a nut, single or in pairs, and enclosed in a non-splitting shell.

Walnut has an unforgettable scent that is rather difficult to describe, I would describe it as “spicy-citrus”.

Walnut trees have a toxic effect on neighboring plants. Known as allelopathy, the phenomenon involves a plants secretion of biochemical material into the environment to inhibit germination or growth of the surrounding vegetation. Allelopathy enhances tree survival and reproduction. Allelochemicals are metabolic by-products of certain plants that, when introduced into the environment, cause growth inhibition by affecting physiological processes such as respiration, cell division, and water and nutrient uptake. Symptoms include leaf wilting and yellowing, or the death of part or all of the plant.

Black Walnuts are often found growing on landscape sites where they serve primarily as shade trees. When certain other landscape plants are planted close to the tree they will wilt and die. This decline in health occurs because the walnut tree produces a non-toxic, colorless, chemical called hydrojuglone. Hydrojuglone is found in the leaves, stems, fruit, inner bark and roots. When exposed to air or soil, hydrojuglone is oxidized into the allelochemical juglone, which is highly toxic.


“Bee Balm” – Frick Park – Pittsburgh, PA – I swear to God this stuff will grow anywhere you put it… Tolerant of juglone… I will say this though… The times I have seen Bee Balm growing near a Black Walnut it has been obviously stunted…

The toxic Zone from a mature tree occurs on average in a 50 to 60′ radius from the trunk, but can commonly be up to 80. The area affected extends outward each year as the tree enlarges. Young trees 2 to 8′ high can have a root diameter twice the height of the top of the tree, with susceptible plants dead within the root zone and dying at the margins.

Juglone is exuded from all parts of the walnut tree. Although it has a high water solubility and does not move far in the soil, small amounts may be injurious to sensitive plants. Plant roots can encounter juglone when they grow within a half-inch from a walnut root. Walnut trees have extremely extensive root systems often reaching far beyond the drip line of the tree, affecting susceptible plants far from the tree.

The accumulation and depletion of toxins in the soil is affected by factors such as soil type, drainage, aeration, temperature and microbial action. Soil microorganisms ingest allelochemicals as energy sources, and metabolic decomposition can render the chemicals non-toxic to plants.

Wet, poorly aerated soil, very common in many urban areas, discourages microbial growth. Plants sensitive to walnuts may be at a higher risk when planted in heavy urban soils that lack organic matter. Toxins adhere to organic matter rather than being absorbed by plants, and organic matter also encourages a healthy soil microbial population.

Mycorrhizal fungi are commonly associated with forest tree roots and are considered necessary for normal uptake functions. Allelochemicals can disrupt the uptake process by damaging the root hairs or by inhibiting mycorrhizial populations in the soil. These different soil factors all have an effect on the accumulation or depletion of juglone produced by the black walnut tree.

So, if you’ve read this far… You are probably wondering if anything can grow under a Walnut… There are actually a large number of plants that will grow near allelopathic trees, as well as steps you can take to reduce the allelopathic effects. Regular cleanup and removal of fallen leaves and fruit is the simplest thing you can do, meticulous maintenance is key.


“White Variation of Red Trillium” – Frick Park – Pittsburgh, PA – I had to include at least one photo of a plant growing under a Black Walnut… Growing on a slope about 40′ downhill from a few Black Walnuts… I would say this is a tolerant plant…

As a side note… I have noticed the real danger even tolerant plants face… Especially anything that is still growing in October… Is the rainfall of 8 ounce nuts falling from 100′ in the air… These falling bastards crush whatever greenery happens to be in their path…

Now to the plants… I have never personally planted a garden under a walnut tree… This article is the result of observation and research… I have always lived near these trees… And ever since I used them as “car grenades” as a child I have been relatively interested in them… When I first learned of allelopathy I became obsessed with the plants that could survive under these trees…

Tolerant Trees – Black Cherry, Crabapple, Dogwood, Elderberry, Hawthorn (my favorite tree), pawpaw, redbud, sassafrass, serviceberry.

Tolerant Shrubs – Black Raspberry

Tolerant Plants – Aster, Astilbe, Bee Balm, Coral Bells, Daffodil, Shasta Daisy, Daylily, Fern, Dutchmans Breeches, Goldenrod, Grape, Great Solomon’s Seal, Hosta, Jack-In-The-Pulpit, Jacobs Ladder, Lambs Ear, Marigold, May Apple, Morning Glory, Sedum, Snowdrop, Sweet Woodruff, Sunflower, Trillium, Tulip, Violet, Yarrow, Zinnia

Tolerant Vegetables – Beet, Squashes, Melons, Beans, Carrots, Corn, Jerusalem Artichoke, Melon, onion, parsnip

Intolerant Vegetables – Asparagus, Cabbage, Peppers, Rhubarb, Tomatoes, Eggplant, Potato

Tolerant Fruit Trees – Peach, Nectarine, Cherry, Plum, Pear

Intolerant Fruit Trees/Shrubs – Apples, Crabapples, Blackberry, Blueberry

Personally, if I had a piece of property with a Walnut Tree on it… I would probably cut that bad boy down and turn it into kitchen cabinets… I’m not a big fan of the flavor of a Walnut, a little bitter for me, plus I find cleaning up the walnuts annoying.

Most walnut varieties are grafted to Black Walnut rootstock, therefore they all contain roughly the same amount of toxins and should be maintained in the same meticulous manner.

plant petunias and question everything – chriscondello

I am not affiliated with anyone other than myself, all the information presented in this blog is provided by me… If you find this information helpful, please consider purchasing a print or two from my online shop…

http://www.society6/chriscondello… Or you can contact me directly at for commissions or locally/personally produced prints… Thank you for reading…

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This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.


Practical Permaculture – Planting Herbs Under Fruit Trees


“Lemon Basil” – Whitney Avenue – Wilkinsburg, PA

Backyard fruit trees are becoming increasingly popular as the locally grown food movement gains strength. A common question is what, if anything, can be grown in the area directly underneath of a tree? Traditionally, orchards were laid out in parallel lines to facilitate easy mowing and maintenance. Little more than grasses and a few native wildflowers could survive the regular mowing, this often resulted in an orchard that requires supplemental nutrients, as well as insect, fungus, disease and pest control measures.

Backyard trees often suffer the same problems that commercial orchards deal with, the only difference is the professionals have tools available that the backyard grower does not. In my personal experience, when it comes to backyard fruit trees, people want an organic permaculture based solution that will work instantaneously. You see, people who live in the city rarely ever stay in the same place for very long. Whether or not the next homeowner wants a fruit tree growing on their property is the issue, I believe many of the urban fruit trees have a lifespan of only a few years, for this reason, every year of fruit production counts…


“Plum Blossom” – Hamnett Place Community Garden – Jeanette Street – Wilkinsburg, PA

If you plant an apple tree… You want to eat an apple…

What can be planted under a particular tree should be assessed on a tree-by-tree basis, every tree canopy is different, no tree is the same. Fall is an excellent time to sow plants under a mature tree, once the leaves fall, water can easily reach the soil. Often times seeds sown in the fall right before the leaves fall, will sit underneath the leaves waiting till spring to germinate… Seeds that germinate before the tree leafs out seem to have the best chances of survival.

Successfully planting underneath of a fruit tree is simply a matter of timing, you want your plants to establish as they would in a natural forest, or while the trees do not have leaves. Many plants, including herbs, can survive extreme conditions once established. Likewise, the actual yield of a herb is often the leaves themselves, which does not require as much light to produce a yield as a fruit or vegetable… Making them perfect plants for an edible guild centered around a primary fruit tree…

Herbs, although extremely tasty as seasonings in our foods, serve a number of other purposes directly affecting the health and wellbeing of a tree. Everything from beneficial insect attraction, repelling pests, Nitrogen fixing, forage and ground burrowing prevention… Herbs can play a role…  Herbs can also be used in the creation of organic oils and solutions that may be helpful in the war against pests and diseases, as the popularity increases so will the availability of these types of products. The jury is still out with me as far as many of these organic/homemade products are concerned. Recent memories of me getting lit up by wasps after using a suggested chili powder and citric acid combo may be tarnishing my thoughts a little bit though…

I’m not one of those permies that will blow smoke up your ass as far as what is possible in the garden. Although plants will grow under a tree, they do not grow with nearly as much vigor as plants that are growing in sunny conditions. In short, don’t think you are going to be able to grow perfect show-worthy specimens under that 40′ apple tree. It is important to remember that what you are doing is primarily to benefit the tree, the fact that you can enjoy them is secondary.


“Allium” – Hamnett Place Park and Ride – Center Street – Wilkinsburg, PA

Because everyone likes a list of plants… This is by no means the end all of lists… As always… It is just a starting point…

Allium – I’m talking from Chives to Ramps, plant them. Even the ornamental varieties will not only survive, but benefit the entire guild from canopy to root. When in full flower, an expanse of Allium can attract so many pollinating insects that from a distance the entire garden will appear to pulse and move. Allium, although tasty to humans, is typically not the favorite food of most foraging and burrowing animals, they will typically forage somewhere else if even the slightest presence of these plants is detected. Garlic is apparently effective as a peach tree borer deterrent, it may be useful as a remedy when planted in very close quarters to an affected tree.

Basil – My absolute favorite herb, cinnamon, lemon, lime, Thai, purple, red, large leaf, Minette, greek globe, spicy globe, sacred… I could go on forever… I grow it in every corner of my garden, I think it is beautiful when grown as an ornamental. Late in the season when the asters and goldenrod are blooming, basil will extend its wispy flower heads high above the other plants in the garden. These flower heads are different shades of pink, purple to white or yellow and attract beneficial pollinators… This year I have even noticed hummingbirds visiting my front yard Basil plants…

Comfrey – You can’t do a list of beneficial herbs without mentioning this storied plant. Comfrey is a well-known nutrient accumulator that has been written about by just about every organic garden writer. Tap-root grows deep, yadah, yadah, yadah… Makes great compost, yadah, yadah, yadah… It is all true… My gripe is really from removal… Because it is practically impossible… I have written about it before in a post titled – Comfrey Cautions – I’m not saying don’t plant it… I’m just saying plant it cautiously as it can get out of hand quickly… And it can become a nightmare for any future people who may occupy your house… Respect the Comfrey…

Oregano – Another staple that can simply be used fresh off the plant in all your favorite dishes, and it is easy as dirt to grow anywhere. Potted plants are typically the normal sales method, often times you can find these plants at a sharp discount late in the year… I like to wait until the leaves have fallen off the trees and then plug them in… It won’t look pretty… But the plants will grow normally in the spring often times starting well before nurseries have them available in the spring…

Sage – Regular old garden Sage, or Salvia Officinalis is often one of the first herbs to bloom in the spring, which in my garden is timed perfectly with many of the neighborhood fruit trees. The distinctive aroma of Sage is also supposed to ward off many pests, kids don’t like it either. When grown under a tree, Sage tends to stretch and grow horizontally instead of vertically. Where the stems touch the ground the plant will root creating a new crown, these can then be dug up and moved around your garden… Or left in place to allow the plant to grow in size…

Mint – Mint is an incredibly invasive perennial weed, I strongly urge you to consider all other options when contemplating planting any variety of mint. The menthol contained in the mint is a powerful insect repellent, it is a common ingredient in many organic insecticides. Mint has a tendency to grow very tall, believe it or not, I have seen it successfully outcompete a newly planted dwarf fruit tree on more than one occasion. Mint also has a tendency to grow thick in the early spring months, this is a problem when it shades the graft union on a dwarf fruit tree typically causing the scion to sprout roots and eliminate all of the dwarfing characteristics of the rootstock.

Lavender – If you have ever had the chance to see a field of Lavender you will not need sold on this Summertime favorite. The dark blue flowers against the silver foliage is simply stunning. Prefers full sun but will do just fine in the shade… Though the flowers are typically more sparse in the shade… Lavender repels fleas and moths, specifically the codling moth making it a perfect companion to just about any fruit tree.

Lemon Balm – You can’t do a list of beneficial herbs without good old lemon balm. Lemon balm contains citronella compounds that deter all sorts of insects… Including the disease carrying nuisance mosquitos that seem to become more dangerous every year. Lemon balm has a tendency to voraciously self seed, clipping the flowers before they go to seed is the only remedy for this.

Dill and Fennel – I am lumping these two together because Fennel is said to be allopathic and therefore should not be planted with anything, except Dill apparently. Both of these plants deter pests. Fennel attracts beneficial insects like ladybugs, wasps and hoverflies… It is also a good flea repellent. The flower heads of both of these plants are an excellent nectar source for a bunch of beneficial insects.

Thyme – Another one of my favorites… Available in practically every size, color and flavor imaginable. Some of them creep along the ground making a beautiful living mulch, while others grow more upright. Both types are simply stunning when they bloom in proliferation, and they too attract swarms of beneficial insects. My favorite is the variegated lemon thyme, I will purposely step on it to release the citrus smell.

Wormwood – The reason I am including this plant is because it keeps animals out of the garden, though it also has a tendency to be allopathic and will in turn kill plants that get to close to it. I only recommend planting it on the outside of the trees drip line to prevent accidents, better safe than sorry. Wormwood is said to repel slugs, moths, snails, black flea beetles and fleas rather effectively, as with all organic compounds I recommend research and experimentation before diving right in.

One of my gripes with permaculture is it offers very few immediate solutions to common fruit tree problems. Although garlic can repel the peach tree borer, it can often take several years for the effects to work, this can be too long for modern families that rarely stay in the same house their entire lives.

plant petunias and question everything – chriscondello

I am not affiliated with anyone other than myself, all the information presented in this blog is provided by me… If you find this information helpful, please consider purchasing a print or two from my online shop…

http://www.society6/chriscondello… Or you can contact me directly at for commissions or locally/personally produced prints… Thank you for reading…

If you would be interested in reading more – Urban Herb BenefitsPlanting Under Fruit Trees

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This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.