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The Horse Apple

“Horse apples!†you may have heard someone exclaim in lieu of a saltier phrase about bulls that means “nonsense†or “malarkey.† Not to worry, those aren’t the horse apples this post is about!  To be clear, this isn’t a post about apples at all, but about one of the more interesting plants you might not have heard of.

When is an “apple†not an apple?  Keep reading about the horse apple and you’ll learn the answer to that question!

Closeup of a horse apple on the ground in the fall.
Most people would never think “apple” when they see a horse apple.

History of the Horse Apple Tree 

The first mention of the horse apple (Maclura pomifera) was in 1804 by Scottish explorer, William Dunbar, who encountered it during a journey from Catherine’s Landing on the Mississippi to Ouachita River.

The plant was often called the “hedge apple” because it grew thorny shoots that became dense and interwoven — these shrubs were planted to form hedges to keep livestock out of gardens and agriculture fields.  These living barriers were described as “horse high, hog tight, and bull strong.†These trees were used for livestock-proof hedge purposes until barbed wire was invented in 1874 and became the preferred method for containing or excluding livestock.

The wood of the horse apple tree was prized for bow-making among the Osage and Comanche Native Americans.  One bow carried a price tag of a horse and a blanket.

Horse apple trees were widely planted in the 1930s as part of President Roosevelt’s plan to prevent soil erosion in the Great Plains states.

Besides being known as a hedge apple, this plant also called the following names:

  • Osage orange
  • Mock orange
  • Irish snowballs
  • Monkey ball
  • Monkey brains
  • Yellow-wood
View of a horse apple tree with fruit.

Horse Apple Tree / Horse Apple Characteristics

A horse apple is a deciduous shrub or tree typically grows 30-50′ tall, but mature trees can grow 45-60′ tall with a 40’ spread.  It takes about 10 years for a tree to fully mature and will take over the space where it’s planted if left unmanaged.  While larger animals are wise to steer clear of this tree, it creates a habitat for birds and small wildlife.

The trees have short trunks with rounded-top canopies.  Their bark is dark and scaly, with deep furrows.  When cut, the stems and branches secrete a sap that can irritate and stain skin.  The trees have shiny, dark green, oval-shaped leaves that turn bright yellow in the fall.  In May or June small green flowers bloom on the tree.

The trees are either male or female.  Female trees develop fruit that falls to the ground after ripening in September and October.

The tree wood makes good tool handles and fence posts – posts have to be set when they’re green because the dried wood is too hard to use staples to attach fencing.  The wood is decay-resistant and because it burns longer and hotter than oak or maple, it makes ideal firewood.

Branches and yellow foliage of a horse apple tree in the fall.

Horse Apple Fruit

Horse apple fruit is 6-8″ in diameter, round, bumpy, and bright green.  It’s the largest fruit of any tree native to North America.

This is a “multiple fruit” that’s formed from a cluster of flowers that fuse together and create a collective fruit (pineapples, figs, and mulberries are other examples of multiple fruit).  They look like little softball-sized green brains, which is probably one reason why kids find them irresistible to throw.

The inside of the fruit has a creamy white center surrounded by yellow-green and contains up to 200 seeds.  If you cut into one, wear gloves to avoid contact with the milky white sap the fruit secretes.

Horse apples, one cut in half.

The fruit has a floral scent “with hints of orange blossoms, pears, apples, and cloves.”  But even with that positive quality, they’re only eaten by a few kinds of wildlife such as deer, squirrels, and birds — most wildlife find the fruit unappealing!

The fruit is also considered a nuisance in landscaping that gardeners have to clean up in the fall.

A squirrel with a horse apple.

Common Uses For Horse Apples 

Horse apples are generally considered inedible by humans (and most animals, including horses).  The size of the fruit has caused livestock fatalities from choking.

The floral industry uses these fruits decoratively in arrangements.

Closeup of a floral centerpiece arrangement including horse apples.

What Does the Horse Apple Taste Like?

To be absolutely clear, we don’t recommend you eat or even taste one of these fruits since things that irritate your skin can also be harmful internally!

There are a few recorded instances of people eating horse apples and their reviews are interesting.  Queen Victoria supposedly tasted one of these and didn’t like it.  At all.

‘Connie Barlow, author of a 2000 book, Ghosts of Evolution, tried hedge apples as well. “The fruit tasted surprisingly good, but more like air freshener than food … delightfully clean, with perhaps a hint of cucumber,†she wrote. But the latex-y sap stained her hands and was difficult to clean off.’

Cooking

There are no cooked uses for this fruit.

Eating raw

This isn’t something you’d want to eat in cooked form, let alone raw.

Canning / Freezing / Drying

You wouldn’t want to do any of these things either.

Recipe Ideas For Horse Apples

There are none.  If you do come across one, we recommend you not make it!

Health Benefits of Horse Apples

When studied, extracts of the fruit have shown significant anti-cancer, anti-inflammatory, and anti-oxidative properties but it’s not a recommended fruit to add to your diet.

Where To Buy Horse Apples

Farmers markets and nurseries sometimes sell these, marketing them as natural insect repellents.  In reality, the amount of compounds in a fruit is too small to be an effective repellent (has to be concentrated).

Three horse apples on a rustic wooden table.

Can You Grow the Horse Apple at Home?

Technically, yes, you can.  But you might not want to unless you have a very specific purpose in mind, such as needing a hedge to keep out livestock (or the neighbor’s dog). 

Growing the Horse Apple Tree

You can grow a horse apple from the seeds of the fruit or plant a shrub.

Where to Plant a Horse Apple

Grows well in zones 4-9.

Choose your location carefully — branches shouldn’t come into contact with pedestrians or cars, which could mean a lot of pruning on your part.

Large horse apple trees trained to form a "tunnel" over a path in a park.
A park path “tunnel” created with horse apple trees.

Sunlight

Prefers a location with full sun.

Soil

Flourishes deep fertile soil, but grows all over the US as a hedge shrub.  It has a shallow root system, but it grows best in deep soil rather than shallow or rocky soil.

Water

While the plant is becoming established, water enough to keep the soil moist.  Once it’s established, you’ll only need to water twice a month to supplement natural rainfall.

Horse Apple Tree Care

These are very low-maintenance plants.

A large, mature horse apple tree in a garden.
A large, mature horse apple tree — the massive roots are covered by moss

Fertilizer

If you feel it’s absolutely necessary, feed with a 10-10-10 fertilizer twice a year — once right before first new growth and then once more 6 months later.

Diseases & Care 

Horse apples are nearly disease-proof.

Pests 

These trees are highly resistant to pests, except one – borers have been reported as a problem.

Spraying

Spraying isn’t necessary unless your horse apple falls victim to borers.

Pruning

These trees must be pruned regularly to manage and control their size.  When female trees are neglected they become fruit-bearing, so diligent pruning can prevent fruit from developing and making a mess to clean up in the fall.

When to Harvest Horse Apples

If fruit develops, it ripens and falls to the ground in September of October.  If you’re using it for decorative purposes, pick it from the shrub or tree during those months. Use pruning shears and wear gloves to protect your skin from the sap.

Closeup of a horse apple on the ground in the fall.

Where To Buy The Horse Apple Tree

There are online retailers that sell horse apple trees and seeds. Starter plug and seeds are available on Amazon.

Wrapping up The Horse Apple

Person holding a horse apple fruit.

We’ll admit this is a strange plant.  It’s not meant for eating, it’s not an ornamental species, and it’s not invasive.  Scientists think it evolved as a food source for the long-extinct giant ground sloths or mastodons.  Yet it’s still with us today.

Most gardening experts would say “Don’t plant this!”  But if you’re someone who enjoys going against conventional wisdom and you enjoy oddball specimen gardening, the horse apple might be right up your alley.

Are you a gardening non-conformist who grows a horse apple tree? Or did you inherit one that was previously planted? We’d love to hear your experiences with this unique specimen in the comments section below! To read about another unusual “apple” that you can eat, read our blog post about the Custard Apple.