Tom's Blog

Wednesday, October 5, 2011

Seeing red: goodbye sumac!

Those who follow these posts know what we think about sumac. Get rid of it! And now that it has turned red, this is the ideal time.

Yesterday, all five of us spent the whole day on sumac. Our intrepid crew (Amanda, Marci, and Susan) worked on some unfortunately large clones in Units 6 and 7 and Kathie climbed among the little bluestem on the Pleasant Valley Conservancy road cut. I did clones in the sunnier areas of three savannas.

Our technique is simple but effective: basal bark with Garlon 4 in oil. We add a red dye to help keep track of where we have been. Since most of these sumac clones have lots of stems (100-200 is not unusual), the dye is necessary.

Most of our backpack sprayers are Solos, which have proved sturdy and reliable. Experience has taught us that it is essential to have the right spray nozzle to keep from wasting herbicide. The treatment consists of a brief wetting of the lower part of each stem.

We have been working on sumac control for the past three years, as time permits. Although our technique is very effective, you don't eradicate sumac with a single treatment, as these clones have impressive underground networks, and root sucker ferociously. Because we top kill our sumac by burning every year, the clones are hard to find nestled down in the tall grass. But now, as is evident in the photo below, the red sumac plants really stand out. Unfortunately, they are also starting to drop their leaves (the unusually warm weather is probably partly responsible), so there is great urgency to get at them now.

While the crew was working on the tallgrass prairie, Kathie was on another tangent, killing the quite large number of small, scattered plants on the road cut above Pleasant Valley Road. In this dry, rocky environment, sumac plants are fairly short, and clones are rare, but if we are going to eradicate this menace we have to get every plant. Working the road cut involves a lot of hill climbing, since after you climb up to the top of the road cut, we have to climb back down and start over a few yards away.

Sumac is a species that grows best in open, sunny areas, so it is less of a problem in our savannas, and no problem at all in the oak woods. Prairie people from here to Nebraska have been dealing with sumac for 100 years. John Weaver, a noted prairie researcher, wrote a paper about sumac in prairies in 1917.

There is, unfortunately, a lot of misinformation about how to eradicate sumac. The data are clear that the only way to get rid of it is by the use of an herbicide, and Garlon is one of the best. (A researcher at Dow Chemical published a paper on the use of Garlon with sumac over 50 years ago.) However, you don't eradicate a clone in a single pass. You have to come back next year and treat again, to kill the inevitable root suckers, and probably repeat again for a third year. (Kathie and I did some careful experiments on this at Pleasant Valley Conservancy.)


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