Tom's Blog

Thursday, October 23, 2008

All out attack on buckthorn

I hope folks don't get too bored with my rants about buckthorn. It really is an awful plant, and much of the literature on its control is either wrong or vaguely described.

There is a short period of time in the fall when buckthorn plants still retain their leaves and most of the native vegetation has senesced. This is one time to use a foliar spray. Since glyphosate did not work well last year, we have switched to Garlon (either Garlon 3A at 5% or Garlon 4 aqueous at 4%). The photo shows our crew seeking out and spraying buckthorn in Unit 10, one of our nicer bur oak savannas. I estimated that in this unit about 60-70% of the surface had buckthorn plants, sometimes single or small clumps, occasionally large clumps.

Our systematic approach to spraying is to mark about 10 foot wide swaths with colored tape, using a compass to run North/South lines. We start at one end of the unit, move through in one direction spraying every buckthorn plant we can find, and then turn and move back in the opposite direction in the adjacent swath. The photo shows three people working side by side. In some cases I worked along side so we had four people (although three is probably optimal).

In several cases there were what can only be called clones. The literature does not mention that buckthorn shows clonal growth via rhizomes, but this is my conclusion after carefully digging up a number of plants. The presence of rhizomes is unmistakable.

An example of what I am calling a buckthorn clone is shown in the photo below. It takes a lot of herbicide to deal with this mess! Fortunately, Garlon does not affect grasses, and we will be seeding such areas next spring.

I estimated the person/hours to spray this unit, and then converted the number into hours per acre. It took us 27 person hours to spray this 2.5 acre unit, which is about 11 hours per acre. Plug in your hourly cost to figure out how much this would cost you.

Remember that we are not dealing here with the original buckthorn shrubs. Those had been successfully removed in 2000-2001. Here we are dealing with the results of the seed bank, and in a site that has had successful annual burns for the past 6 years!


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