Tom's Blog

Wednesday, July 21, 2010

Problem with pale Indian plantain

Pale Indian plantain (Arnoglossum atriplicifolium) is a species that is often found on lists for savanna restoration planting. It also grows well in mesic to wet mesic prairies. When we started savanna restoration work about ten years ago, we included this in our species mixes. Unfortunately, it has thrived too well in some of our restorations, and we are now having to deal with the consequences.

One of the "worst" infestations was an open savanna area in Unit 11A, where it had been planted about 9 years ago. In the southeast corner of this unit, near the "saddle" road, it had formed a massive "wall" of plants that shaded out virtually everything else. In fact, it had eliminated one of my best purple milkweed sites.

Our intern crew had some time yesterday, so we put them onto this infestation. Since pale Indian plantain is a perennial, herbicide use had to be part of the process. And in order to protect any other species, we cut the plants with loppers rather than brush cutters.

As the above photo shows, these stems had grown more than head height. They were so dense that nothing else could grow. Because of the massive amount of biomass, the cut stems were hauled off the site and taken to our brush/weed pile. Three truck loads of material were removed!

Each cut stem was immediately treated with Garlon 4, as if it were a woody plant, using a hand spray bottle. The photo here shows how large the stems were. Most of the plants were multi-stemmed.

Even though these plants are not woody, this treatment procedure is appropriate, and experience with other species has shown that it works. (We have used the same procedure for reed canary grass and creeping bellflower.) The point is to get the herbicide down to the roots, so resprouting will not occur.

This job took six people all morning to complete. The photo below shows the weed pile after all the cut material had been tossed on it. Quite a mess! Quite a job!

I am not sure why Arnoglossum thrived so well in this particular site. In many other of our savannas it seems much better behaved. It is a little disconcerting to have to spend all this effort to control a native species that is really desirable and is found in many savanna species lists. According to Iltis and Cochrane, it is "conspicuous but rare." A Google search did not turn up any particular problems. Hopefully, a lot of the other natives that had been in this site are still present in a suppressed state and will return!


Anonymous Anonymous said...


July 22, 2010 at 8:56 PM  

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