The Montana Noxious Weed List Advisory Committee met in Helena in early December.  Marijka Wessner attended the meeting, representing MNPS in Marilyn Marler’s absence (how can a weed meeting compete with Japan and Thailand?).

   The committee voted to recommend a change to the Administrative Rules of Montana pertaining to weed categories.  A new Category 4 Watch List would be added to the three weed categories already designated in the rules.  The purpose of the Watch List for newly invading weed species is to allow the gathering of more information and monitoring for occurrence and spread.  Information collected may be used to justify future inclusion in Categories 1, 2 or 3.  The same criteria used to place species on the existing list would be used to designate a watch species.  One advantage of having a legally designated category for watch species is it gives the Department of Agriculture the authority to regulate the sale and transport of species suspected of being invasive in the state.

   One such species is Japanese knotweed (Polygonum cuspidatum).  The committee reviewed a petition to place the knotweed complex, also including giant knotweed (Polygonum sachalinense) and Himalayan knotweed (Polygonum polystachyum) on the state noxious weed list.  The petition, submitted by Marijka Wessner of the Missoula County Weed District, pointed out the invasive quality of these plants in Greenough Park and other areas near Missoula and the plants’ ability to spread vegetatively.  Several states, including California, Oregon and Washington have added Japanese knotweed to their noxious weed lists.  Japanese knotweed was introduced into the United States as an ornamental and continues to be sold for landscaping purposes.  Adding the knotweed complex to the Watch List will allow a moratorium on sale and transport of the shrubs while the plant’s distribution and status are reviewed.  The committee is doing more research on the knotweed complex in the state and is expected to make a recommendation in April.  All in all, a Watch List sounds like a good idea.  It is much better to deal with a potential problem when it is first noticed, instead of waiting for a full-blown invasion.