Plant Story--Red Cedar, Really a Juniper of Course

If you live in the central United States, especially in cattle country, you can’t miss red cedars, the one evergreen native to the plains. Solid, evergreen and fragrant, city people like them as yard plantings.

Red cedar is a misleading name because it is in the genus Juniperus. It could be called a juniper. Most of its relatives use juniper as their common name. They are gymnosperms, plants with needle-like leaves, cones and no flowers, cypress plant family, Cupressaceae. Red cedar is related to the common juniper (Juniperus communis) from whose berries Europeans make gin and not as closely related to cedars, genus Cedrus, such as the Cedars of Lebanon described in the Bible. Eastern red cedar, Juniperus virginiana, grows from the Atlantic Ocean to west-central Nebraska, Kansas and the Dakotas. West of that and up into the Rockies, the very similar tree is Rocky Mountain juniper, Juniperus scopulorum. Southern Colorado’s juniper of the pinyon pine-juniper community which extends into New Mexico is the one-seed juniper, Juniperus monosperma. Farther west there are additional species, see for example USDA/plants. (link)

Where eastern red cedar and Rocky Mountain juniper meet they hybridize, creating plants that defy plant identification books. Different regions of the U.S. have different native plants, largely because climates differ, but where two related species meet, often there is a hybrid zone, as in this case. 

Rocky Mountain juniper in Rocky Mountain forest

In the Rocky Mountains, Rocky Mountain juniper is just one of the conifers, and not nearly as commanding a presence as ponderosa pine or blue spruce. In the plains, however, eastern red cedar is, for hundreds of miles, the only native conifer. Consequently it has received special attention. Tribes such as the Cheyenne respected the red cedar because, unlike almost every other plant, it remained green all year. It never seemed to grow old. Red cedar featured in Plains tribes creation stories, for example among the Omaha, and was the wood of choice for ceremonial objects because of that. Many tribes, including the Omaha, Kiowa and Lakota, used its fragrant branches for incense in religious ceremonies. Steam with red cedar was used in sweat houses and other purification ceremonies. 

Across the plains, the durable wood, deep red as if dyed with blood, was fashioned into both ordinary tools and special objects such as flutes and lances.  

Medicinally, people have long used red cedar, for colds and congestion, both as steam and as a tea. In Europe, people used their local juniper trees in the same way, indicating important shared chemistry in these trees and similar observations by people on both continents.

Settlers also appreciated eastern red cedar, building with it and using it for coughs and colds, when they could find it.

Red cedar is much more common on the plains now than it was 100 years ago. Chiefly, that is because settlement of the plains has reduced the frequency of wildfires. Red cedars are very flammable. The resins that give them the pleasant smell let the branches easily catch fire, even when green. A red cedar can survive a fire that sears its lower branches, but if the whole crown burns, the tree dies. Unlike cottonwoods, red cedars do not regrow from the roots. Note the how solitary red cedars are: there is never any suckering.

Red cedar does have some fire-resistant characteristics. The trunk isn’t easily ignited. If the branches are high enough, a ground fire won’t seriously injure the trunk. A second fire-resistant characteristic is the dense shade cast by the tree. Very little light comes through, suppressing plants, especially grasses, that might grow underneath it. With little fuel under the red cedar, it is harder for a fire to catch in its flammable leaves.

Young red cedar, less than 2' tall
Too short to survive if it was surrounded by grass in a fire

Before settlement, fires swept through the five foot tall grasses of the eastern plains—what is now the Corn Belt—every three to five years. A red cedar seedling would be low to the ground and so incinerated. Farther west it was drier with less plant cover, so fires were less frequent. There, drought generally confined red cedar to moister areas, such as along streams.

With the removal of wild fires, not only have red cedars been allowed to grow in peace, but they have spread, thanks to birds. Although we often call red cedar fruits berries, actually they are small cones, as in pine cones, but covered in a sweet fruity flesh to make them attractive to birds. All sorts of birds eat red cedar berries, then defecate the seeds that were inside the berries somewhere across the plains, spreading red cedar. The result is a bloom of red cedar in states like Kansas, Nebraska, and eastern Colorado. The settlers would have been pleased, but today’s ranchers are not. Cows don’t eat red cedar.

Juniper with nearly-ripe "berries" (fleshy cones)

Berries of juniper species vary from very edible to so resinous as to be both unpleasant and dangerous to eat. A good general rule for all potentially edible plants is: if it doesn’t taste good, don’t eat more. Writers of books on edible plants find neither eastern red cedar nor Rocky mountain juniper very palatable and marvel that Indians used them so extensively. Plains tribes did sometimes eat juniper berries plain, but mostly they were used to spice other foods, for example pounded with dried meat into a form of jerky. A few of our red cedar berries go a long way as a condiment or spice. The berries of American Juniperus species are safe to eat, at least in small amounts, but the berries of some very similar-looking European species are considered poisonous so don’t try berries from cultivated trees unless you have actually identified the tree. 

Immature juniper cones

Red cedar is dioecious, with “male” plants whose cones make only pollen and “female” plants whose cones receive the pollen and develop into the berries. Red cedar’s pollen is released by the male trees into the air, to swirl around until it lands on a female cone. Clearly, this kind of pollination means that the more pollen a male tree throws into the air, the more female cones it is likely to reach. Like many pollens, there are distinctive compounds in the pollen of red cedars that cause allergies. With the increase in these trees across the plains, this is more of a hazard to people with allergies, and for a longer period of time each spring.

Dioecy also means that unlike, say, wild plums, where each tree usually has some fruit, only half of the red cedars have fruit—the female trees. The fruits take three full years to ripen, receiving pollen the first year, filling out as green berries the next and ripening to a blue-purple the third year. Difficult as all this seems—finding another tree of the opposite sex as a mate and waiting three years for ripe seeds—it is working well for red cedar, they’ve already turned pastures in the Midwest into red cedar forests.

Enjoy the fragrance of these trees.

Comments and corrections welcome.

Kathy Keeler, A Wandering Botanist

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