Flint Hills, Tall Grass

A weed, otherwise known as an Eastern Redcedar, grows amid tall grasses of the prairie.

Weeds attack even the best of gardens. Those who manage a landscape, any landscape, from the simplist garden to the largest ranch spread, struggle constantly to keep weeds out.

But what are weeds, actually? Why is one plant considered a pest to be eliminated and another plant is a welcome guest to be nurtured? It comes down to competition, I suppose, since plants, like people and other wild animals, compete for resources in their respective landscapes. Such is the case for one of the worst weeds in the tallgrass prairie of the Flint Hills, the eastern redcedar.

Redcedars, or just plain cedars to most Kansans, are known technically as Juniperus virginiana, which to lovers of the prairie translates roughly from the Latin into a bunch of cuss words. There are other invasive species that are harder to control, but none stand out as so visible a reminder the prairie is a fragile ecosystem that needs some help to survive. Cedars can quickly overtake a pasture and eliminate the native tall grasses. By some estimates, if the spread of cedars in a particular field is not stopped, then in as little as 40 years, the entire area will become a cedar forest and the prairie grasses entirely lost.

Cedars are trees, of course, and their wood is valued for closets and chests everywhere, since the wood repels moths. The trees spread with the help of birds, who eat the blue, berry-like seed pods and then deposit the seeds after it passes through the bird’s digestive tract. So whenever you see a cedar, think where it came from.

Controlling the spread of cedars isn’t unusually hard. They do not resist fire very well, so some regular regime of controlled burns will usually keep the cedars out. It is becoming more difficult to fight them off, however, even with regular burning. It’s sort of the prairie’s version of invasion of the body snatchers, but more on that in a moment.

All of this brings me to the question of why there are so many cedars in the Flint Hills. Since they are not good for the prairie, and fire keeps them out, then why are they becoming more and more numerous?

Just the other day, for example, I was driving home from Nebraska on highway K-177, just west of Tuttle Creek Reservoir. There are some beautiful prairie landscapes along that route, with the enticing curves of grass-covered flint hills rising up over the lake. To the east, the wind-blown deposits of loess soils over the Flint Hills permits quite a bit of cultivation, but there are still native tallgrass prairie grasses dominating many pastures along the route. All of a sudden on my trip, however, the grass disappeared and I found myself driving through a cedar forest. Just north of the bridge over Fancy Creek – land once explored by George Sibley and Isaac McCoy, the prairie grass had given way to thick, dense stands of cedars.

The simple explanation is the lack of fire. Stop burning and cedars will soon take over. The threat is growing, because the more cedars that grow, the more blue berries will sprout from their branches. And the more blue berries, the more birds will come for the feast. After the feast, the birds fly off and deposit the seeds with the rest of the crap in other pastures. That is why I said earlier it is becoming more difficult to keep the cedars out. There are more and more seeds being spread.

To be fair, I’m sure there are many people who love cedars and look at them as a valuable asset. As mentioned above, the wood of cedars is valuable material for many projects. The wood resists rot and makes for good fence posts. Others plant cedars as a windbreak to protect homes and farm installations from wind and snow. Quite a few animals can find shelter in the branches. (Some native prairie birds, however, are actually on the decline because of the influx of cedars, but I’ll save that story for another post)

Cedars, however, are a weed in the prairie landscape. They grow well in the thin soils of the Flint Hills and survive on reduced amounts of moisture. When a cedar is established, it changes the soil chemistry and native tallgrass plants are eliminated. When an entire field is overtaken by cedars, the soil is changed to such an extent it may take years to recover the lost prairie ecosystem, even if the cedars are cut down and burned.

How big a problem are cedars in the Flint Hills? I don’t have the information to put a number on the problem, but anyone who drives through the Flint Hills regularly and loves the prairie will tell you there are far too many fields dominated by these weeds.

Consider, for example, the Google satellite view below. A simple fence row splits this field in two. Above the fence, the field is burned regularly. Below the fence, fire has been eliminated for several years. It’s not hard to miss the difference cedars make.

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So if you are lucky enough to own even a small part of the prairie, don’t neglect your garden. Keep the weeds out.