Blooming multiflora rose in a pasture.
Multiflora rose has been a common topic of conversation among pasture-based livestock owners for as long as I can remember. Although considerable progress has been made in understanding and controlling it, one doesn't have to drive far around the countryside in Pennsylvania to see there is still room for improvement. The spread of multiflora rose in Pennsylvania has caused it to be designated as a noxious weed in the state.
Control of this problem often involves an integrated approach. There are physical, biological, chemical, and cultural means of control. Multiflora can be controlled, but it takes considerable effort.
Start by thinking about prevention and cultural aspects. All the things we normally talk about in progressive management of pastures will help to keep multiflora from becoming established in the first place. Maintaining pH and fertility, planting adapted forage species, rotational grazing, and leaving plenty of residual after grazing, are all things that can go a long ways toward preventing multiflora rose from becoming established.
But what do we do if there is already an infestation of multiflora?
On the biological side, there have been some interesting developments. Probably the most promising of which was the arrival of rose rosette disease (RRD). RRD is a virus that is spread by mites. Within two years of infection with RRD, the entire multiflora rose plant will be dead. RRD has spread across a large part of Pennsylvania over the last several years. In my region of the state, areas that once had nasty infestations of multiflora rose are looking very different as RRD takes out large stands of multiflora. When we first started hearing about RRD moving northward years ago, I actually had farmers asking if we could bring in mites from areas with RRD and release them to allow them to do their work in spreading RRD. A good indicator of how badly despised this weed is.
Another biological option is the inclusion of sheep and/or goats into the grazing system. It is no secret that goats like to browse and will strip leaves and bark from multiflora bushes. In my experience, sheep will strip leaves and eat new growth that is within their reach. Ultimately, goats are probably more effective in eliminating multiflora rose. As a cattle owner, you may not have any interest in raising small ruminants, but there may be producers who would bring either of these species to your farm to help get rid of multiflora. It would even be possible for a small ruminant owner to target certain areas on your farm by using portable net fencing to keep the goats/sheep confined to one location.
On the chemical side, there are several options to gain control. These treatments can be categorized into soil, foliar, thin-line, and basal bark treatments. Herbicides recommended as being effective on multiflora rose are 2,4-D, Banvel /Clarity (dicamba), Crossbow (2,4-D LVE + triclopyr), Roundup (glyphosate), Metsulfuron-methyl 60DF, and Spike 20P. The selection of which herbicide to use is based on several factors. For more information, consult the Penn State Agronomy Guide orMultiflora Rose Management in Grass Pastures. As always, consult the label before using any of these materials and pay particular attention to the grazing restrictions after use.
On the physical side, we can sometimes mow, dig, pull, or bulldoze multiflora to eradicate it. Mowing repeatedly can destroy the plant's ability to manufacture food. Research has shown that control of multiflora with mowing requires 3-6 mowings for more than one year. Another means of physical control is excavation, which involves digging or pulling the plants out of the soil. All roots with shoot buds need to be removed. Of course the success of physical eradication depends on the size of the plants and the size of the infestation. Large plants and large infestations may require heavier equipment. Physical means of eradication can become expensive when attempted on a larger scale.
Finally, once you have gained control of multiflora rose on your farm, don't relinquish it. As mentioned earlier, a well-managed pasture and grazing system will generally not be overrun by multiflora. A pasture sward that is managed will be able to out-compete weed threats. The occasional multiflora plant may turn up underneath a fence, but can be easily dealt with at that point.