Here’s How Often Walnut Trees Actually Bear Walnuts

Ripe walnuts on the tree

Walnut trees are rather distinctive because of their large, baseball-sized green fruit. Inside those fruits are some of the most delicious nuts: walnuts! But just how often do walnut trees produce walnuts?

Walnut trees will bear fruit once per year. However, the amount will vary each year. Occasionally, walnuts will not produce any fruits during the growing season because of stressors such as drought, pests, or lack of nutrients. Walnut trees bear walnuts around 7 years of age.

There are many trees in the walnut family, each with its unique characteristics. Let’s check them out and talk about how often you can expect walnuts on your tree!

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Which Walnut Trees Produce Walnuts?

Walnut trees are found throughout the world in temperate and warm climates. There are a variety of different species, but only certain types are available in the US.

The four most common trees that produce walnuts in North America include:

  • Black walnut
  • English walnut
  • Butternut (white walnut)
  • Heartnut

All walnut trees produce walnuts, but the number of nuts produced will depend on the weather and the available nutrients. 

Walnuts are cold-sensitive according to Utah State University. They don’t like super cold springs or early frosts in fall. One exception is the heartnut tree, which is native to Japan and is cold-hardy.

Their sensitivity to cold means that walnut trees may bear less fruit when the area they grow has late frosts in the spring or early frosts in the fall before the tree has time to harden off.

Black walnut and English walnut are the two most popular trees used for nut production. California is the country’s number 1 walnut producer. Oregon and Utah are two more states that produce walnuts, among others.

The walnut that most of us recognize and eat is from the English walnut tree. Black walnuts are still grown and used for nut production, but the shells are more difficult to crack and the taste is far bolder than that of an English walnut.

These commercially important trees are grown in orchards similar to how apples or other fruit trees are grown. Orchards keep the trees smaller than their natural height of over 100 feet. 

Orchard walnut trees are chosen selectively based on their trait to yield high amounts of nuts and resist pests and disease. 

Those who have a walnut tree in their backyard may observe low walnut yields, which could be because of the genetic makeup of the tree or the conditions under which it grows

Or your walnut tree might drive you crazy because it produces too many walnuts!

How Often Do Walnut Trees Bear Fruits/Walnuts?

Walnuts in the wooden bowl on the table under the walnut tree.

If it seems like we are interchanging the word fruit and nut in this article, it’s because we are! Nuts are considered the fruit of the walnut tree.

If you don’t believe me, the U.S Forest Service even defines nuts like walnuts as fruits as they have a single dry seed, hard shell, and protective husk.

Nut-bearing trees produce nuts enclosed in some kind of protective husk, which is then protected by another outside layer. This last layer is leathery or waxy.

In the case of the walnut tree, the outer layer can be green or a washed-out yellow-green color. The inner ‘nut meat’, as it’s called, is the actual walnut. 

Walnuts are an important food source for wild critters as well. Squirrels especially like to nab walnuts and hide them away for winter.

So, how often can you expect your backyard walnut to bear these delicious and healthy fruits, nuts, whatever you want to call them?

Walnut trees will produce a crop of walnuts every year starting around age 7 to 15, depending on the species. High yields occur about every 2 to 3 years, with low yields in between.

The best nut yields will not occur until the tree is over 20 years of age.

If you want to learn more about how many walnuts you can expect on your tree, check out our piece, How Many Walnuts Grow On A Tree? Full Walnut Timeline.

Why Isn’t My Walnut Tree Producing Any Walnuts?

Have a walnut tree, but it’s not producing any nuts? What gives? 

If your walnut tree does not seem to produce any nuts or the yields have been consistently low, there are several reasons this is happening.

Late Frost

Grape vines and old walnut tree in frost

We mentioned earlier walnut trees are not big fans of cold weather. They need plenty of time to prepare for winter by slowing production and growth when the days get shorter.

The same can be said for spring. Walnut trees may bloom too early in the spring and then the blooms are killed off by a late frost in April. In this case, the flowers and catkins needed for pollination will not bloom. Without pollination, the fruits will not develop.

Lack Of Nutrients

Nutrients are important for any tree to survive and thrive. Fertilizers are typically packed with the nutrients that trees need, such as phosphorus, nitrogen, and potassium, depending on the species.

Once a tree is established, it does not need any help to get the nutrients it needs because the roots of the tree can extrapolate the minerals from the soil.

However, some soils that are disturbed by humans will lack proper nutrients for walnut trees. Leaf litter is an important organic material that is degraded in the winter and absorbed into the soil, providing nutrients for the tree the next year.

In areas like HOA suburban neighborhoods or cities where leaf litter is required to be picked up, trees will suffer more because of it.

If a walnut tree cannot get the proper nutrients it needs, it cannot transport them to the stems and leaves, and the tree will struggle to produce fruits and new buds.

According to the University of Missouri Center for Agroforestry, the most important nutrients for a walnut tree are:

  • Nitrogen
  • Phosphorus
  • Potassium
  • Calcium
  • Magnesium
  • Iron
  • Manganese
  • Zinc
  • Boron
  • Copper

If your walnut tree is struggling to produce fruit and you notice some browning leaves or early leaf drop, your tree may need some fertilizer to help it out.

You can purchase something like Jobe’s Organics Tree Spikes for Fruit and Nuts. This product comes as a spike, which you hammer into the ground around your walnut tree’s dripline.

The spikes offer a constant, slow release of the required nutrients your walnut tree needs. It comes with a pack of 8, so you can surround your tree with the spikes, keeping your tree happy and healthy.

Some reviews mention dogs like to dig up the spikes, so check your work every few days to make sure Fido is not getting into trouble!

Pests

There are hundreds of different pest insects to all kinds of different trees. Beetles, caterpillars, ants, flies, and mealybugs can all affect trees, among others.

The walnut husk fly is the most common pest of walnut trees. After emerging from the soil in July, adult husk flies will mate and lay eggs beneath the surface of the walnut husk. Once the eggs hatch, the maggots (gross) feed on the walnut husk for a few weeks.

Once they are rolly-polly from eating the husk, the maggots drop to the soil to pupate and start the entire process over.

The walnuts of your tree are still edible despite the flies and their maggots, but the nuts are often stained black and are unsightly. If you know maggots have touched the nut, would you want to eat it?

While pests may not cause your walnut tree to produce less fruit, they may cause the nuts to be uncollectable or useless.

There are a few ways you can control these pesky husk flies so they do not bother your walnut tree.

  • Remove All Fallen Nuts: Picking up all the fallen nuts as soon as they fall can remove some of the larvae still on the nuts, reducing next year’s population.
  • Use Traps Paired With Spray: You can use sticky fly traps to gauge when the adult husk flies are emerging from the soil. Once the traps fill up with the flies, it’s time to use a spray to keep them off your walnut tree.

A sticky trap like Trappify’s Hanging Fly Stick Trap will work great at attracting the husk flies and trapping them. It comes with a hook so you can hang it from any branch of your walnut tree or on a nearby shepherd’s hook.

As soon as you notice husk flies lurking about, use a spray like Monterey’s Garden Insect Spray with Spinosad Concentrate. This is a concentrated product, so it will need to be mixed with water. 

Always follow the directions on the label for the proper mixing levels.

It is okay to use this product directly on your tree as it is approved for organic gardening. Pairing the trap with the spray is a great idea if the first two suggestions do not seem to work for your husk fly problem.

Alternating Pollination Periods

Another reason your walnut tree is not producing as many nuts is because of the lack of pollination.

Walnut trees are monoecious, meaning both the male and female parts are present on the tree. This typically means that the tree can self-pollinate.

However, with the walnut tree, self-pollination does not always happen. The male may disperse its pollen when the female flowers are not receptive. If the trees cannot pollinate, fruits will not form.

How Many Years Will A Walnut Tree Produce Walnuts For?

Ripe walnut inside his cracked green husk in nut cluster among the leaves on walnut tree in orchard close-up in selective focus

Whether you enjoy gathering fallen walnuts or cannot stand them littering your yard, at some point your walnut tree will age and slow down.

In orchards, walnut trees only last for about 35 years, according to the University of California, Davis. In the wild, walnut trees can live for hundreds of years, but on average they last around 200 years.

If your walnut tree is young, do not expect it to stop producing nuts soon. 

As all trees age, they slow their growth, and eventually, growth becomes minuscule. This is about when a tree reaches its maximum height. At this point, walnut trees will continue to produce fruits, but the yields will be much lower than when the tree was a strapping young adult.

The walnut tree will struggle to defy gravity to transport water and nutrients to the rest of the tree, which will limit flowering and therefore fruit production.

How To Make A Walnut Tree Not Produce Walnuts

The large fruits of a walnut tree can dent cars, thump noggins, and surprise the heck out of you if you’re walking beneath a tree while the fruit is falling.

Not to mention, walnut fruits will litter your lawn as they fall, creating a mess of green and blackened fruits and husks. Is there any way to stop this from happening?

If you are not interested in collecting the walnuts and would rather not litter your yard with them, there are a couple of things you can do.

Use Fertilizer

This may seem counterproductive. After all, doesn’t fertilizer help trees grow faster and provide more nutrients?

Well, that’s kind of the point. We want to flood the tree with nutrients to promote new growth.

The more energy the tree is putting into growing, the less energy it is putting into fruit production. Fertilizers rich in nitrogen should do the trick!

Clip New Walnut Blooms

This option is only viable while the tree is young. You can use a pruning tool to clip off new blossoms in the spring. 

This prevents the flowers from ever blooming, which means no pollination, which means no messy walnuts to clean up in the fall.

Cut Down Walnut Saplings

Squirrels help propagate walnut trees all over the place. They bury their nuts in the soil and then forget about them. These buried nuts then grow into new walnut trees.

As the saplings emerge, you’ll want to clip, cut, or saw them down. Having more than one black walnut tree in your yard increases the chance of wind pollinating, which will increase fruit yields. 

While the tree itself can self-pollinate, yields are smaller than if more walnut trees are around to help with pollination.

Black walnut trees may harm your garden as well. This might drive you to get rid of them on your property. To learn more, take a look at 20 Plants Not To Grow Under A Black Walnut Tree.

How Do I Know What Kind Of Walnut Tree Is In My Yard?

If there are tons of varieties of walnut trees, how are you supposed to know which walnut you have growing in your backyard?

Black walnuts are the most common walnut trees in the wild. Butternut trees will also grow in the wild but are not as common as black walnuts. English walnut trees are grown strictly in orchards and are not common to see in the wild.

If you’d like to learn more about the difference specifically between black walnut trees and other walnut varieties, take a look at our article: 8 Differences Between Black Walnut Trees and Walnut Trees.

Let’s check out some differences between these two trees so you know exactly which tree is littering your yard with fruits and nut husks!

Walnut Tree Height

Height at maturity is a big indicator. Black walnut trees will grow up to 100 feet, while a butternut tree’s maximum height is only 60 feet.

However, if your tree is not fully grown, it can be difficult to tell the difference between the two, as they have many similar characteristics.

Walnut Tree Fruit

Another way to tell the difference between black walnut and butternut trees is to check out the actual nuts once they fall off.

Black walnuts are round, while butternut walnuts thin out at the ends in a tear-drop. Sometimes they will have points at both ends, and sometimes one end is rounded while the other is more pointed.

Walnut Tree Bark

Just like height, the bark of your walnut tree may be difficult to distinguish when the tree is young. But if your tree is mature, the bark should appear different between the two.

Black walnut trees typically have heavily furrowed, dark brown bark. Butternut walnuts, or white walnuts, have smooth greyish white bark

That’s A Wrap!

As this article comes to a close, you should be packed to the gills with walnut knowledge! Who knew there was so much to know about walnut trees?

To recap, walnut trees will bear fruit once per year, ripening in the fall. High yields of walnuts happen every 2 to 3 years, with low production in between.

You can expect your walnut tree to continue producing nuts through its lifespan, but as the tree ages, fruit production will continually decrease. If you do not want the walnuts at all, there are a few steps you can take to lessen or eliminate walnut production.

References

Avanzato, D. (2010). TRADITIONAL AND MODERN USES OF WALNUT. Acta Hortic. 861, 89-96 DOI: 10.17660/ActaHortic.2010.861.11

Cannella, C. and Dernini, S. (2005). WALNUT: INSIGHTS AND NUTRITIONAL VALUE. Acta Hortic. 705, 547-550 DOI: 10.17660/ActaHortic.2005.705.80

Chudhary, Z., Khera, R. A., Hanif, M. A., Ayub, M. A., & Hamrouni, L. (2020). Chapter 49 – Walnut. Medicinal Plants of South Asia, 671-684.

Mamadjanov, D.K. (2005). WALNUT FRUIT FORESTS AND DIVERSITY OF WALNUT TREE (JUGLANS REGIA L.) IN KYRGYZSTAN. Acta Hortic. 705, 173-176 DOI: 10.17660/ActaHortic.2005.705.20

Molyneux, R. J., Mahoney, N., Kim, J. H., & Campbell, B. C. (2007, October 20). Mycotoxins in edible tree nuts. International Journal of Food Microbiology, 119(1-2), 72-78.

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