Those following these posts are aware that we have been working hard to completely eliminate sumac from the natural areas Kathie and I manage. Some of the details can be found on earlier blog posts.

Sumac eradication: http://pvcblog.blogspot.com/2012/10/sumac-eradication-techniques.html
Sumac biology and control: http://pleasantvalleyconservancy.org/sumac.html

A Search on Tom’s Blog will lead to further posts on this topic.

The sumacs at Black Earth Rettenmund Prairie have been a special target of these efforts because it is a high-quality site that had lots of sumac, and its small size makes it convenient to canvas. Our work there began seriously in 2009, at which time there were several areas with large amounts of sumac. Detailed surveys using GPS were made in 2010 and 2011, as shown on the map.

GIS map of the 2010 (red dots) and 2011 (yellow circles) sumac surveys. The red polygons show the presence of unusually large clones. #8 is the Narrows and #7 is the Wide Narrows (near where the photo below was taken).

Beginning in 2010 crews worked through the prairie, mainly in the late fall when the sumac “red” made location easy, and basal barked (with 20% Garlon 4 in bark oil) every stem found. To keep track of the work, the top of each stem was broken to indicate that it had been treated. Several large clones were dealt with separately, as described in the links cited above.

By 2012 we were starting to get on top of the problem, and by 2014 eradication was almost complete.

Yesterday I made a survey of the Saddle and Wide Narrows areas, where large clones had been present. Happily, I found practically no sumac. The photo here shows a small single sumac stem that was buried within the prairie grass and forbs.

Because the intense sumac red has not developed completely in these small plants, a crew will be deployed for a mid-October follow-up survey. The members of that crew will be equipped with spray bottles of Garlon 4, and each sumac plant found will be basal barked.

View across the Wide Narrows looking north (photo taken 9-25-2015). In 2010 there was a large sumac clone here. In June 2015 this area had a large population of wood lilies and in August there was blazing star.