Observe those Osage oranges!

Ian Stewart

Happy New Year everyone! If you’re looking for an interesting New Year’s Resolution to get you outdoors, why not seek out and learn about a different tree every month? This is exactly the time of year to spot one of Delaware’s most distinctive trees – the Osage orange.

The Osage orange (Maclura pomifera) is a small to medium-sized deciduous tree native to the Midwest that was originally restricted to a relatively small stretch of Arkansas, Oklahoma and Texas. It is not related to oranges but is in the Mulberry family. The name refers to the bright orange color of its wood and the Osage Nation, a midwestern Native American tribe who used the wood for making bows and apparently supplied early settlers with young plants.

The exposed orange roots of a fallen Osage

Although their original range was small, Osage oranges are now found throughout the lower 48 states after lines of them were planted to provide windbreaks in flat open landscapes such as farmland and isolated homesteads. Lines of Osages were also planted throughout the rest of the country to act as natural thorny fencerows for housing livestock and to delineate driveways and land borders, which is why you most often find Delaware Osages arranged in rows on either side of old country roads. Coverdale Farm Preserve’s famous ‘Avenue of the Osages’ contains no fewer than 72 of these striking trees which were probably planted over a hundred years ago.

Coverdale Farm’s famous ‘Avenue of the Osages’, with fallen fruit in foreground
Gnarly, orange-tinged bark of an Osage

The easiest time of year to identify Osage oranges is in the middle of winter as the bare trees now reveal their distinctive gnarled orange-tinged bark made up of many twisted strips. Some trees still bear their large green fruit, commonly known as ‘monkey brains’, although most of these have now fallen to the ground. Be careful – if they fall on a sidewalk or road they become a slippery hazard to pedestrians and motorists alike!

Osage orange fruit with knobbled surface
Interior of an Osage fruit with some seeds

Osages occur as either male or female trees but only the female trees produce the softball-sized fruit which contains several small seeds within its gooey white flesh. Although the fruit is edible almost all animals ignore it as it is tough, unpalatable and exudes latex, so the clusters of monkey brains simply remain where they fall until they decay. Squirrels do eat the seeds however, which may be why you see so few young trees mixed in with the old ones.

Interestingly, almost every Osage I see has a poison ivy vine growing up its trunk, perhaps because the vine finds it easy to grip onto the furrowed bark. Next time you are a passenger in a car being driven along a country lane, try to spot some rows of Osage oranges. If you spot some it might make you resolve to learn about our local trees in 2019!

This Osage was cut down at Coverdale and has about 90 growth rings, suggesting it was at least 90 years old. The poison ivy vine seen in cross-section on the left of the trunk had 19 growth rings so it had been attached for many years.

6 thoughts on “Observe those Osage oranges!”

  1. You might have mentioned the nasty thorns. Also, if you think on burning this wood, the heat produced from dry Osage orange wood has qualities often compared to coal. However, the wood actually burns so hot you can easily damage a wood stove if you’re not careful and it makes showers of sparks when you open the stove door or stoke an open fire, as in a fire place. It should be cut and split while it is still green.

  2. I briefly mentioned the thorns as these help to make them such good fence rows. You’re right to warn people about the thorns though, years ago I punctured my bicycle tire when cycling beneath one and found a big Osage thorn in it! Interesting point about burning the wood, I didn’t know about that. Thanks!

  3. I remember my Forestry professor telling us the old saying for Osage Orange was “Horse high and hog tight” because a horse can’t jump over it and a hog won’t go through it because of those thorns. I found a reference to the saying that includes “bull strong” in middle. I guess a bull won’t push through there, either.

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