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Black Walnut Tree: Meals With A Darkish Facet

For those who’ve been within the shade of a black walnut tree, you know the way beautiful it’s. Couple that with a black walnut harvest, and it’s straightforward to understand why walnut is a food regimen staple for folks dwelling in North America. 

Not solely are the nuts scrumptious, and stuffed with diet, the bushes are straightforward to develop. They’re a pioneer species, sweeping by means of barren environments to take residence. The walnuts are additionally the principle supply of meals for the jap fox squirrel. 

The black walnut tree will get a nasty rap as a result of pure herbicide it secretes in its leaves, nut husks, and roots. These components irritate human pores and skin and put livestock in peril. The herbicide additionally makes it troublesome to develop different crops across the black walnut tree. 

However don’t let that cease you! Black walnut bushes have their disadvantages, however sure crops can survive round close to them. So long as you’re cautious and put on gloves, caring for them is a worthwhile (and engaging) endeavor. 

Good Merchandise At Amazon For Rising Black Walnut:

Fast Care Information

Black walnut tree
The black walnut tree has a nasty rep as a result of it’s allelopathic. Supply: Sue1454
Widespread Title(s) Japanese black walnut
Scientific Title Juglans nigra
Days to Harvest 120 days
Gentle Full solar
Water Simply above 2 inches per week
Soil Fertile, well-draining
Fertilizer Granular, excessive nitrogen 
Pests Black walnut curculio, walnut shoot moth, ambrosia beetle, squirrels
Ailments Fusarium wilt, thousand cankers, nectria canker

All About The Black Walnut Tree

Black walnut fruit
Black walnut fruit on the tree. Supply: dmott9

The black walnut tree (Juglans nigra) is a local tree within the Japanese United States. You’ll discover it thriving in riparian areas alongside river and creek banks. The black walnut has a longtime place amongst Apache peoples, who eat uncooked and cooked nuts in myriad methods and use them for topical medication. At present, the black walnut thrives all through temperate zones of North America. It’s used for its dependable hardwood. The nuts are additionally a outstanding business crop the world over. 

The black walnut tree is a deciduous tree that grows 25 to 100 toes tall. The black walnut roots are taproots, extending 10 toes underground. As a result of taproots make moisture retention troublesome, the tree lives alongside river and creek banks. Darkish inexperienced walnut leaves are compound, pinnate, and comprise 15 to 23 toothed leaflets which can be 1 to 2 toes lengthy at maturity. They emerge in early spring from dense, bushy lateral buds. Terminal buds are heart-shaped and bundle collectively in threes. The tree’s cover spreads as extensive as it’s tall.  

In Might by means of June, female and male black walnut flowers bloom with spiked feminine flowers and male catkins and are yellow-green in shade. With profitable pollination by wind or bugs, walnut fruits type in September by means of October. Fruiting doesn’t happen till the fifth 12 months of progress, and a full harvest might not happen till 20 years. The life span of a black walnut tree is roughly 100 years. 

Juglans nigra bushes are related to the chemical juglone, which prevents the expansion of sure different plant species. Juglone is secreted within the roots, walnut shells, and leaves. Close by crops might expertise herbicidal results, however not all crops are prone to juglone. However there are numerous species of crops that don’t have susceptibility to juglone of their roots, and plenty of are floor covers. So some crops are appropriate in shut proximity to black walnut.

The fruit husks are harmful to livestock and pets. This generally causes seizures in canine and laminitis and colic in horses. Juglone dissipates inside 2 to 4 months, making bushes and tree components helpful in well-aged compost.

Not solely had been Juglans nigra bushes well-liked amongst Native People, however early settlers loved the black walnut as effectively. Black walnut hardwood can be prized for its sturdiness and is commonly used as a straight-grained veneer. The veneer is coveted amongst “walnut rustlers” who steal it from lumber yards. Non-veneer wooden is utilized in furnishings and fence posts.  


Plant Juglans nigra saplings in fall. Keep away from rising black walnuts in containers. They’re too giant. As an alternative, select a website with a minimum of 12 by 12 toes between every seed or sapling. Preserve the tree out of direct winds in full solar, in well-draining, wealthy, and moist soil. Juglans nigra accommodates pure herbicides that sluggish progress of prone crops. Don’t plant the tree close to crops delicate to juglone, particularly different bushes. Many crops can face up to juglone, however in case you’re not sure, don’t danger it.  

Dig a gap giant and deep sufficient to accommodate the black walnut taproot with out twisting or distorting it. Place the tree within the gap, and change the filth. When the opening is ⅔ full, add water, and press the soil down, eradicating any air pockets. Then fill within the remaining soil, mounding the filth across the base of the tree, leaving a couple of inches between the trunk and the soil. Mulch effectively across the planting website for moisture retention. 

Propagate black walnuts through grafting. Connect the twigs of viable, productive bushes onto one other rootstock, like English Walnut or Pecan. Choose a size of twig that includes the present 12 months’s progress. Minimize 6 to eight inches of twig with a pointy knife or pruning shears. Then make 3 vertical incisions within the bark of the rootstock, and minimize the spherical finish of the twig right into a 45-degree angle. Put the slicing into the three-section and affix them collectively, wrapping them with aluminum foil. Then cowl that with a plastic bag and tie it across the base. Inside 3 to 4 weeks, new progress signifies a profitable graft.

A Be aware on Planting Location

Black walnuts in the husk
Retrieve fallen husks to forestall extra juglone unfold. Supply: BlueRidgeKitties

As we’ve talked about, black walnut roots, walnut hulls, and leaves secrete the pure herbicide juglone. Different nut bushes, younger bushes, and sure different plant species can have slowed progress or no progress because of planting close to black walnut. The fruit husks are harmful to livestock and pets. This generally causes seizures in canine and laminitis and colic in horses. Don’t plant this tree the place pets and livestock can snack on any a part of the tree. All the time put on gloves when dealing with the husks as pores and skin irritation and marking can happen from dealing with the husks.

English walnut bushes are sometimes grafted onto black walnut rootstock. Whereas English walnut accommodates decrease quantities of juglone than black walnut, it may very well be grafted onto black walnut. 

Juglone deteriorates rapidly, and primarily spreads by means of the foundation system across the tree. It’s potential to develop raised mattress crops under the tree so long as leaves and husks are eliminated promptly after they fall. So long as you’re not going to make use of the compost from the tree components instantly, it’s helpful there. Walnut will not be possibility for a meals forest, as a result of it takes 2 to 4 months for the juglone to go away the bottom the place a tree was planted.

There are numerous species of crops (a lot of them floor covers) that develop simply tremendous within the floor round these bushes. Right here’s a fast listing of among the number of crops that may develop inside shut proximity to black walnut, however there are others too!




Canopy of a black walnut
The black walnut’s cover supplies numerous shade. Supply: ShamanicShift

Let’s discuss methods to look after black walnuts in your backyard. With the proper care, you’ll have a beautiful, wholesome tree, producing harvests for the remainder of your life. 

Solar and Temperature

The black walnut tree wants full solar to thrive, at a minimal of 6-8 hours of direct solar per day. Black walnuts develop greatest in zones 4 by means of 9. Established black walnut bushes are adaptable to each tropical warmth and sustained winters. Saplings have a more durable time in chilly and want a tree wrap. The black walnut tree does greatest when there are a minimum of 170 frost-free days in a 12 months. Very best temperatures vary between 45 and 65 levels Fahrenheit. Sustained freezing temperatures at 28 to 32 levels trigger extreme harm to the unprotected. The warmth isn’t any drawback in any respect for this southern native tree. 

Water and Humidity

A black walnut tree wants 1 inch of water per week, and just a little greater than 2 inches in its fruiting section in summer time. In most areas, spring and fall shall be accompanied by sufficient rain to fulfill the 25-inch water requirement. Place a soaker hose or drip irrigation across the drip line of the tree, and water completely within the morning to a depth of three to six toes as soon as per week in spring and fall, and a couple of to three instances per week in summer time. If it rains usually, there’s no want to offer further irrigation. 


Make sure the place you planted your bushes is wealthy in natural matter, loamy, and well-draining. If the earth is excessively sandy or silty, add some peat to retain moisture. Black walnut grows greatest in soil that was labored a minimum of a couple of toes in. If you until, add in well-rotted compost, leaf mildew, peat moss, and lime if the pH is very acidic earlier than planting. Black walnut grows greatest at a pH of 6.0 to six.5 however tolerates 5.0 to eight.0. Compacted earth isn’t any good for tree progress or producing fruit.  


To extend the expansion fee of your bushes, apply an ammonium sulfate granular fertilizer (21-0-0 NPK) in spring after the primary 12 months of progress. All the time apply fertilizers a minimum of 1 ½ toes away from the trunk of the bushes. In the summertime, because the tree begins to fruit, add a full spectrum granular fertilizer (15-15-15) in the identical method because the ammonium sulfate. Apply these fertilizers yearly. 


In younger bushes, take away branches that time inward or downward. Minimize the aspect branches to six inches to advertise higher fruit harvests. Wait till mature bushes drop walnuts to the bottom in fall to prune the branches. Take away stubby branches first on the trunk. Take away diseased and broken branches or those who cross one another or the trunk of the tree. Prune aspect branches to be shorter than cover branches. Take away suckers from the bottom. By no means prune greater than 25% of the branches per 12 months. Nuts drop from the tree after they’re prepared for harvest, so no have to take away them. For those who’re involved about juglone within the backyard, rake up the leaf matter, bark, and dropped twigs. The husks particularly ought to be eliminated as a result of they comprise the very best focus of herbicide. 

Harvesting and Storing

Black walnut harvest
As walnuts drop, remember to harvest them promptly. Supply: taratara69

One of the best a part of rising black walnut within the backyard is the harvest! Right here’s methods to get nuts out of your tall walnut tree, shell them, and extract them. 


Walnuts drop from tall heights to the bottom of their husks after they’re prepared for harvest. Collect them in a basket within the early to mid-fall. Put on gloves when performing the harvest to make sure your arms are protected against irritants. Discard any broken walnuts.

To hull them, both place them in a bag in your driveway, and drive over them, or drill a 1 ⅝ inch gap in plywood and hammer every by means of. Each strategies take away the husks from the outer shell. Then, compost the remaining husks. Keep in mind to permit the compost to interrupt down for a couple of months earlier than utilizing it. Wash them, and treatment walnuts that aren’t going to be eaten by laying them in a single layer in a cool darkish place for a number of weeks.

One vital post-harvest step includes raking up any hulls, brown leaves, and branches across the base of the tree. Particularly in case you’re rising tomatoes, peppers, butternut squash, sure shrubs, and pine bushes, the removing of the tree matter will forestall herbicidal results. Compost the tree matter for a couple of months, then display out any remaining wooden so it could proceed to compost down.  


Retailer walnuts inside their shell in burlap sacks at room temperature for as much as 1 12 months. Enable shelled walnuts to dry for a day or two earlier than storing them within the fridge in an hermetic container for a couple of months. Frozen shelled nuts hold in jars or plastic baggage for two or extra years. Throw them into meals as wanted, and add vitamins to your favourite meals.


Eurasian red squirrel with black walnut
Squirrels equivalent to this Eurasian pink squirrel discover black walnuts tasty. Supply: stanzebla

Issues generally occur once you develop a tall tree like black walnut. Right here, we’ll focus on a couple of points that may come up. 

Rising Issues

For those who planted on the improper time or uncovered a sapling to bitter chilly, it takes on chilly harm and should even die. Guarantee there’s a wrap current at planting in these zones which can be vulnerable to snap freezes.

When the tree doesn’t get sufficient moisture, it could get sunburned. Make sure you’re soaking the highest 2 to three toes of the earth round mid-fall, particularly in summer time months. 

The commonest subject folks expertise when rising black walnut is harm to close by crops on account of juglone within the walnut’s roots and plant components. Preserve your pine, peppers, and tomatoes freed from black walnut particles. 


Black walnut curculio is a protect bug that feeds on the vitamins in walnuts, and deposits its larvae inside them, damaging yields. The larva overwinters within the backyard floor under. Whereas there are not any natural pesticides that reliably management curculio, handle them culturally by eradicating any prematurely fallen nuts as quickly as potential, and disposing of them within the trash. Mow across the trunk frequently.  

Walnut shoot moths and their reddish-brown larva feed on the flowers and buds of black walnut. They go away small spherical holes in buds, inflicting improper flower progress and decrease yields. Take away any broken components of the plant as they present shoot moth harm. Then use corrective pruning within the dormant season to remove infestations.  Spinosad is efficient towards the moths and their larvae.

Ambrosia beetles bore into trunks and should unfold fungal spores within the course of. Flooding is a situation during which these beetles thrive. Keep away from waterlogging the backyard once you water. They wilt foliage and go away boring mud exterior the small holes they make. Bait them in early spring and late winter with ethanol traps. Pyrethrin sprays utilized after you entice a couple of beetles management them and the fungus they unfold. Reapply each two to a few weeks till traps now not have beetles in them.

Squirrels like to eat walnut fruit. They may even pelt you with a nut or two! To maintain them off, reside entice them and launch them in a close-by squirrel habitat. In saplings, cowl the fruit with a mesh bag. There’s not a lot you are able to do when squirrels need to get to nuts. In mature specimens, just a little meals for the squirrels received’t dampen your harvest. 


Fusarium wilt is a fungal soilborne illness. The fungus causes yellowing leaves, defoliation, and a wilting cover. There isn’t any therapy for fusarium, so prevention is crucial. Guarantee the bottom is well-draining across the tree, and apply mycological bio-fungicides that can cut back the unfold of fusarium fungi.

Thousand cankers is an aggressive fungal illness that impacts single branches of plant species, shrubs, and nut bushes inflicting yellowing and leaf wilting. For those who discover scarring, wilting, and powdery white signs related to thousand cankers, contact your agricultural extension workplace to find out the following steps. There isn’t any treatment for the illness.

Nectria canker seems as sore-like wounds on branches and trunks that turn into pink, orange, and yellow fruiting our bodies. That is attributable to two totally different fungal pathogens and doesn’t have any related therapy aside from corrective pruning. An arborist ought to be consulted to debate the cankering. 

Ceaselessly Requested Questions

Q: Are you able to eat black walnuts from a tree?

A: Sure, however hull and shell them first. Use gloves when dealing with hulls. 

Q: How lengthy does it take for juglone to interrupt down?

A: 2 to 4 months. 

Q: Are black walnuts toxic?

A: To not people, however components of the crops are poisonous to livestock. 

Q: Are black walnut bushes poisonous to canine?

A: The husks are poisonous to canine. Fruits throughout the walnut shells will not be as poisonous, however smaller canine could also be extra prone than giant canine. Seek the advice of your vet in case your canine consumes among the shelled fruit. Alternatively, hold them away from pets altogether to keep away from any points.

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