Tuesday, December 2, 2008

Why control native shrubs?


A question has been raised about why we are trying to control native shrubs such as sumac and gray dogwood. Good question. I need to be reminded occasionally that our efforts to control native shrubs are not so obviously beneficial.

First: we don't try to eradicate these shrubs, but just work to keep them under control. These shrubs are all clone formers, and have the potential to spread and completely suppress other native vegetation. An example reported at the last Prairie Conference was of a prairie which over the years had become half sumac. Because of the dense shade under the sumac, virtually no "good" prairie plants can grow.

The photo above is of a sumac clone on a county highway which threatens to completely occupy all the space. This might be all right on a highway, but do we want our prairie to look like that?

In addition to sumac and gray dogwood, other native shrubs that are clone formers are brambles, prickly ash, and red osier dogwood. Quaking aspen is a clone-forming tree which we also control.

All of these woody plants are top-killed by fire, but fire will not get rid of them. After a few fire-free years, they will be dominant again.

Several of these native shrubs are favorite wildlife food. Because of this, we always leave a few large clones for the birds and butterflies. But if we are going to have the high diversity of prairie and savanna forbs and grasses that we crave, we must control the shrubs, whether they are native or nonnative.

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