Selected Case Studies

Black swallow-wort, multiple sites.  This vine produces pods that release airborne seedpuffs (like milkweed) which then carry to new locations.  There are numerous sizable infestations of black swallow-wort up the Connecticut River corridor from the Putney area as far north as Randolph.  Spreading along valleys and transportation vectors, the vines have established colonies as far west as Bridgewater on Route 4.  Preliminary results of control work were published in 2012, and follow-up treatment in 2013 found only 4 to 6 plants where there had previously been several hundred.  The method was simple; the vines break off at ground level rather than pull out completely.  They are stubborn, but three visits in one season really sets them back, and after that it’s just mop-up.   Published in The Ripple Effect in July, 2012

Summer Science, Pomfret, VT.  This project takes place on school grounds during the summer, with students treating garlic mustard and Japanese barberry.  Since the work involves children, I will release the annual write-ups by specific request only.  The young students earn a little money,  get credit for their work, learn how to use spreadsheets, learn about job safety,  and even report on their accomplishments to the school board.  Almost 500 barberry plants pulled or flush-cut so far over four summers.  The annual summaries may be available in the Pomfret town reports.  Or email me.

Giant hogweed, E. Montpelier, VT.  This site is on a town-owned parcel containing a historic cemetery and an overgrown drainage.  Neighboring properties have also been impacted; the site is roughly three acres in size and treatment began with the 2012 growing season.  I broke the site up into three distinct treatment areas, and one approach in particular yielded amazing results.  View the reportPhotoAerial View.  Video and a powerpoint is also available, but they are huge files.

Giant hogweed, Woodstock, VT.  Town funding of this control project closed out in 2012 after six years of manual treatment.  Happy to report that in 2015 individual plants are still hanging on, but I’m seeing no new germination.  The seed bank appears to be exhausted, but I’ll continue to proof that.  The report is available from the town of Woodstock.  With property ownerships mentioned by name, a sensitivity to privacy and property values requires that I not publish this report except by special request.  Feel free to email me.

Wild parsnip, multiple sites in Vermont and New Hampshire.  These attractive biennials are capable of rapid spread across open landscapes.  Unfortunately, the sap of the plants is sunlight-activated and seriously harmful to human skin.  The key is early detection and proper timing of treatments. With a seed life of five years, I am seeing great results on sites once I get past Year Three.  While I do not encourage anyone to take on wild parsnip themselves, I do encourage them to call me the first moment plants are noticed.  One site that had been perfectly “clean” for years suddenly had 49 wild parsnip scattered across the fields in 2013.  This definitively tells me that equipment from elsewhere brought the seeds to the property (since the area gets either mowed or brush-hogged every September), but I was really surprised to see 49 plants.  That’s an awfully big number with over 2000 seeds per plant.  On the positive side, solarizing appears very successful against wild parsnip.  When set up properly, landowners accomplish many years of control in just 60 days. Finally, I’m alarmed at the fact that I observed wild parsnip in full flower on 24 October; the extended growing season is not helpful here.  Pre-treatment photo

Multi-flora Rose, two sites in Randolph, VT.  I measure Multi-flora Rose  infestations by the number of orbits or concentric circles radiating out from the original bush.  MF Rose spreads like raspberries and Japanese barberry.  The arcing stems come into contact with the ground and then root, creating a ring around the parent plant, so I always ask about the number of orbits observed at an infestation.  MF Rose is stubborn, especially in full sun, but if it does not cause erosion or rip up a stream bank, I pull the bushes with a Weed Wrench or the WHaTS tool.  They come back strong for at least two growing seasons, but it gets easier to continue cutting back the re-growths.  I cut or stress this plant every time I’m on site, up to eight times in a growing season.  I cannot really report yet on the effectiveness of flaming.

Common and glossy buckthorn, Norwich, VT.  These two species respond to treatment very differently.  My approach revolves around intercepting seed rain.  Stress or impact these infestations by early July, and that should prevent or certainly reduce any fruiting.  My observations show that three treatments over two growing seasons kill off the majority of the buckthorn.  Since I do not like climbing over huge piles of brush, I tend to girdle these dense stands, but common buckthorn is hardly phased by a 6-inch wide girdle.  Amazing.  Glossy buckthorn dies off completely above the girdle band, and re-sprouts less than half the time.  When I do cut larger trees, I leave them at waist-height.  This makes them much easier to find when I come back through, and it saves my shins from getting shredded by ankle-high spikes.  On the second and third passes, I just cut a couple inches lower to lop off all the re-growth.  Buckthorn can also be uprooted, but that gets much harder to do by hand once they gain some height.

Japanese knotweed, Randolph and Royalton, VT.  Intensive control began on the Randolph site in 2011 with ten cuttings, followed by nine cuttings in 2012 and eight cuttings in 2013. That’s an aggressive approach, but it seems to have been hugely successful.  The patch was definitely well-established, but after three aggressive seasons, I’m projecting a much simpler follow-up phase: three more years, but only six treatments annually.  And whereas the cutting took two full hours in the first year of treatment, I should be able to knock it out in a half hour going forward.  Honestly, the biggest challenge is finding the stalks amidst all the other plant life.  I’ll focus on the May / June timeframe to flush-cut any re-growth.  There are perhaps eight to ten young trees, various species, still surviving in the area.  I planted them, but they are not yet dominating the site.  The work in Royalton concerned a riverbank that had been ripped up by Irene flooding.  Two hundred meters of gently sloping, full-sun riverbank was saved from the import of Japanese knotweed fragments.  Knotweed was never allowed to take hold, and grasses have come in strong on the site.  Again, I planted perhaps three dozen trees to accelerate the recovery.

By way of updating the knotweed sites, they look great in 2016.  In Randolph a site that was roughly 75 feet long is now dominated by other plant species, to include 9 trees.  When I comb through, I find and pull around 30 knotweed stems the width of spaghetti strands.

The Shrubs (Barberry, Honeysuckle, Autumn olive, Burning bush)  I take these on with size as my guide.  If there is no threat of creating erosion, I pull smaller shrubs; that requires the Weed Wrench as they get larger.  When I encounter huge shrubs, the approach is simply to repeat stress events.  This can involve removal of all branches to leave just the skeleton.  Re-growth is then stripped on succeeding visits.  Flaming is effective during fall months, but getting perfect conditions can be a challenge.  I cannot leave a smolder in the ground below the root collar, so flaming is somewhat a last resort.  Three stress events over two growing seasons is enough to kill all but the toughest shrubs.  I find them to be most difficult when rooted in shallow water; honeysuckle thrives in such a bog setting.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s