[MAIPC] Fallopia japonica

[Locke, Andrea S]

In addition to the methods provided, I’ve found success using stem-injection with glyphosate, especially for areas adjacent to water. My understanding is also that japanese knotweed (Reynoutria japonica) doesn’t produce viable seed, however giant knotweed (R. sachalinensis) and the hybrid bohemian knotweed (R. x bohemica) do. Looking at the photographs provided, this is probably bohemian, not japanese. Leaf size and shape are good characteristics to use for differentiation. In my area, bohemian is the most common knotweed, by far.


Andrea Locke
WNY PRISM Coordinator
716.878.4708
lockeas at buffalostate.edu



From: MAIPC [mailto:maipc-bounces at lists.maipc.org] On Behalf Of Judy Fulton
Sent: Friday, September 2, 2016 12:00 PM
To: MAIPC <maipc at lists.maipc.org>
Subject: [MAIPC] Fallopia japonica


I was recently sent the attached two photos of what looks like Fallopia japonica (aka Polygonum cuspidatum and Reynoutria japonica), which were taken in May. Apparently, the homeowners, whose property borders Back River in Baltimore County near Rock Creek Park, Maryland, are quite pleased with their decision to plant “Japanese bamboo” to reduce erosion.

I’m concerned because Fallopia japonica can live in salt environments, such as salt marshes. I’ve been informed that the mouth of Back River is at the southern edge of the fresh water zone of the Chesapeake Bay with average salinity of 6 ppt, but salinity can range from <1 ppt to 10 ppt depending on weather conditions.  I’m assuming that the pieces of rhizomes that might break off in a major storm could survive in Back River to colonize other areas, especially if the storm reduced the salinity in the river. Does anyone know if this is correct? Also, would the seeds remain viable if they were transported to another location by Back River?

If the homeowners were convinced to remove their Fallopia japonica, what would be the best way to eradicate it so near the water? Something like Rodeo plus a non-ionic surfactant?

Thanks for your advice.

Judy
____________________________________________

Judith P. Fulton
Consultant, University of Maryland Extension
Master Gardener, University of Maryland Extension
Chair, Maryland Invasive Species Council Subcommittee on Invasives Lists
410-337-3701
jfulton5 at gmail.com<mailto:jfulton5 at gmail.com>
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