Monday, January 23, 2012

Fragrant Sumac in the Prairie

Being a native plant doesn’t mean that the plant cannot also be invasive.  I consider a native plant to be invasive if it becomes established in a desired ecosystem and has the ability to replace the existing plant complex with something else.  The invasive designation is based on management goals.  This means that a single species can be both a desirable native plant and an invasive plant depending upon where it is found at Blue Jay Barrens.  A good example of this is the Fragrant Sumac, Rhus aromatica, shown here invading a tall grass prairie, but growing a hundred yards away as a desirable native understory shrub.

This process of ecosystem replacement is called succession and is a natural and perpetually occurring event.  Grassland is taken over by brush – Brush gives way trees – Trees grow into forest.  If the process was never disrupted, all we would have is forest.  The idea of ecosystem management is to inject intentional disruptions that hold succession at a particular stage. 

The Fragrant Sumac forms a dense stand of branches that eventually eliminates the tall grasses and prairie forbs.  The branches of the sprawling shrub can be overtopped by the tall grass, so the incursion is often hard to detect until the sumac is well established and expanding its territory.

I find a lot of value in Fragrant Sumac when it grows in a field edge or shaded understory situation.  These buds will develop into early spring flowers that are visited by a wide variety of butterflies, moths, flies and beetles.  In my management activities, I try to leave plenty of these shrubs in a condition to bloom.

When a patch of Fragrant Sumac gets out of control in the prairie, I work to reduce its vigor or eliminate it entirely.  This clump of sumac was mowed and will be sprayed in the spring.

There’s very little left in the way of prairie vegetation at the heart of the sumac infestation.  The green grasses are bluegrass and fescue, both of which are non-native and undesirable in the prairie.  I’ll eliminate the grass along with the sumac.  Deciding what must go and what can stay is one of the hardest jobs of ecosystem management.  When you get to the point of actually eliminating a species, you just hope that your decision to take that action was correct.


  1. Is that a nice, healthy Formica exsectoides mound in the background? Careful to mow around. :~)

  2. Hi James. You're right about the mound ID. I'm always careful not to damage the mounds. I once confined a guest to my front porch because he kicked a mound after I had told him to leave it alone.