I haven't talked a lot about the second component of this experiment, looking at herbicide vs allowing native vegetation to grow under the trellis, but keeping it mowed. We are looking at this in our research vineyard at the LIHREC in Riverhead. This is a replicated trial in Merlot. Treatment one is mowing only all season long, treatment two is herbicide only during the season (in this experiment it is post emergent only - glyphosate), treatment three is mowing with one herbicide at the end of June and treatment four is mowing only with one herbicide treatment at the end of July. The idea behind this work is that if a grower didn't want to give up herbicide entirely, is there a key time during the season when an application is more beneficial, in terms of the groundcover's impact on vine growth. This work is in the fifth season and we have seen impacts on vine size. The vines that had herbicide season long have been larger than those with mowing only. The treatments with a single herbicide had more variability from year to year. The interesting thing that came out of this experiment is that a grower may be looking to limit growth in vines. There could be an especially vigorous variety or block where this strategy would be beneficial in managing those vines. In our trial, although the vines with cover are smaller, they are by no means struggling so the impact is not that extreme so far. But we have a few more years of this experiment to flesh this idea out. To see more in depth results of this experiment check them out at our website: http://ccesuffolk.org/grape-research/.

Here are some pictures of the mowing only treatment before and after it is mowed.

Here is a photo of two treatments next to each other - herbicide only vs mowing only.