[APWG] Mile-A-Minute, Polygonum perfoliatum

[Michael Schenk]

I've been doing a great deal of tearthumb removal this year, and I'd like to share some observations.  

The tool I used is a lightweight collapsible hoe, with three tines opposite the hoe blade.  These tines worked well for grasping the vines with a twirling action, like spaghetti on a fork.  The barbs on the vines make a mass of vine self-adhesive.

I have attempted to get the root with each removal.  The key to that is to pull on the vine slowly, so that the root hairs release from the soil before the vine stem parts.  There is a characteristic ripping feel transmitted through either the hands or the tool if the root comes out, as contrasted with a popping sensation if the stem breaks.  Don't try to remove so many stems at a pull that the vines part before the roots pull.  If the vines are well-entwined in shrubs or firm stems, a slow sweeping motion with the tool near the ground will uproot the vines before the barbs let go of their substrates.

I began removal in May, and continued last week (June 21-23).  The plants in May were small and the roots came out readily, but the small size made them harder to spot and  reach.  I simply hoed many smaller plants.  By June 9, vines in sunny locations were covering shrubs and climbing tree stems, and were going to seed.  The roots were still loose and small enough to come up easily.  In large masses, I would gather an armful.  The stems would diverge to many root locations.  I would then use a tool or free hand to pull roots one small area at a time, until the entire mass was uprooted.

By June 16 I began seeing rare seed pods turning blue.  The roots were becoming firmer and harder to uproot before the stem broke.  By June 23, seeds in green pods which I opened were blue.  I don't know if this indicates an ability to germinate.  The roots were firmer yet, and I had a greater percentage of stem breakage versus uprooting.  Tree seedlings and small shrubs were being bent to the ground under the vines.

My overall strategy was to attempt 100% removal in hard-to-access spots and edges of the infestation. In easy-to-access spots, I concentrated on speed, removing stems which were going to seed.

I examined areas which were infested last year.  Those areas which we worked on in July had relatively few vines.  The areas we worked on after seed set had many young vines this year.  We used weed-whackers last year to cut the vines near the ground in some heavy infestations.  Those spots did not show evidence of heavy regrowth from the roots -- the wall of dead vines was not bridged by regrowth, although new vines from this year were climbing the old dead vines from last year.  I conclude that there is a large advantage to removing old vines, since new growth uses these for ladders.  Winter removal of dead vines is a good idea.

Vines which were removed last year and which bore blue seeds were bagged on the spot and left to compost in situ, so as not to spread seeds.  I dumped several of those bags out this Spring, and saw little germination from the piles, so I conclude that this treatment killed most of the seeds.

Germination appears to be continuous through the season.  Areas which were absolutely cleared of vines June 9 had vines growing June 23.  It will be necessary to perform periodic removal at a site until first frost, I believe, until the seed bank is exhausted.

In this process, I broke some pokeweed and raspberry stems, uprooted a few small tree seedlings, and broke several black cohosh flower stalks, but overall there was very little damage to the native plants.  Bedstraw vines tended to be pulled along with the tearthumb.

I observed growing ends of a minority of tearthumb vines which had holes in the leaves, and observed one Japanese beetle chewing on a tearthumb vine.

I would estimate that we removed 90% of tearthumb from several thousand square feet in about 80 hours field work.

Areas which received early effort last year were dramatically less dense in tearthumb this year than areas which received quick, late attention.

Best regards,
Mike Schenk


-----Original Message-----

>Message: 1
>Date: Tue, 26 Jun 2007 07:20:42 -0400
>From: "Marc Imlay" <ialm at erols.com>
>Subject: [APWG] Mile-A-Minute, Polygonum perfoliatum
>To: <apwg at lists.plantconservation.org>
>Message-ID: <5u1lfe$csqjiv at smtp01.lnh.mail.rcn.net>
>Content-Type: text/plain; charset="us-ascii"
>
> 
>
> 
>
>Three of us used garden rakes followed by hand pulling in Little Paint
>Branch Park, Beltsville MD on 
>
>June 22, 2007 and removed 20% of the massive 25' by 100' patch of
>Mile-Minute in an open area 
>
>in 2 hours. For example, the three volunteers in 15 minutes used the rakes
>very gently to remove 
>
>about 80% of the Mile-a-Minute in a 20' x 20' patch about 50% invasive vine
>cover over 50% native 
>
>cover including sensitive fern, asters, sycamore and sweet gum seedlings and
>Virginia creeper. The 
>
>herbaceous natives were not damaged and it was then easy enough to hand pull
>the remainder in 
>
>30 minutes. When we tried to pull very hard at another spot, native plants,
>including a virgin creeper, 
>
>were damaged. Hand pulling alone would have been seen as hopeless and
>herbicides would have 
>
>damaged the natives. Bio-control is having mixed success according to
>reports. Cheers.
>
> 
>
>Marc Imlay
>
>Laura Malick
>
>Mike Breen 
>
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