Control Methods

  • Biological Control: Using herbaceous animals or diseases as a means to control.
  • Manual Control: Manually pulling stem and roots using hands, “Weed-Wrench”, or other simple tools for control of individual plants.
  • Mechanical Control:  Simply cutting or girdling individual plants, mowing, “weed whacking” or similar action of cutting large number of plants with tools.
  • Chemical Control: Cut stump: Involves horizontal cutting or girdling of a stem, then applying herbicide according to directions given and on herbicide container. Application of herbicide can be done by special equipment or paint brushes.
  • Chemical Control: Foliar spray: Applying herbicide according to directions given and on herbicide container, by spray, special tool, or paint brush on leaves of plant.

 
Species Specific Controls:

Norway Maple Acer platanoides

Biological Control

None known.

Manual Control

Hand-pull smaller trees (saplings), girdle larger trees.

Mechanical Control

Cut, or girdle trees most effective, may require re-cut to control re-sprouts.

Chemical Control: Cut Stump

Apply 8% triclopyr applied directly to cut.

Chemical Control: Foliar spray

Apply 41% glyphosate applied to foliage.


 

Japanese Barberry Berberis thunbergii

Biological Control

None known.

Manual Control

Uproot plants in the spring after leaf out, when soil is still damp. Root fragments can re-sprout, ensure that all root fragments are removed and be diligent about re-sprouts.

Mechanical Control

Cut in the late summer prior to seed production.

Chemical Control: Cut Stump

Apply 25% triclopyr or glyphosate solution mid-summer to fall.

Chemical Control: Foliar spray

Apply 2% glyphosate in water with surfactant, early in season before other plants have matured. Late summer during fruiting is seen as most effective, yet damages surrounding plants.

Notes/ comments

If lacking berries, plants can be left in place to decompose. If berries are present, bag and remove from site.


 

European Barberry Berberis vulgaris

Biological Control

None known.

Manual Control

Hand-pull, ensure that root stock is removed.

Mechanical Control

Control by mowing at least three times per year, for a number of years.

Chemical Control: Cut Stump

Apply 25% glyphosate to cut stem in mid-summer to fall.

Chemical Control: Foliar spray

Apply 2% foliar glyphosate mid-summer to fall. Application of triclopyr is most effective in early spring.

Notes/ comments

If lacking berries, plants can be left in place to decompose. If berries are present, bag and remove from site.


 

Oriental Bittersweet Celastrus orbiculatus

Biological Control

None known.

Manual Control

Entire plant should be hand pulled when the soil is moist including the root portion then bagged and disposed of in landfill, burned or fully dried out. Cut portions will re-sprout and continue to grow.

Mechanical Control

Cutting as close to root collar as possible, every two weeks in growing season. Continue to cut in this manner year after year until root supply is exhausted.

Chemical Control: Cut Stump

For larger vines cut about two inches above the ground and immediately apply 25% glyphosate or triclopyr. Use trimmer or saw to make a band around the bark of the vine apply 20% triclopyr in basal oil with penetrate to cut. 

Chemical Control: Foliar spray

Apply 2%- 8% triclopyr mixed in water and a non-ionic surfactant, ideally in October. For dense low patches: cut entire patch early in growing season, one month later, apply 1-2% solution of triclopyr using backpack sprayer.

Notes/ comments

This plant is fairly tolerant of glyphosate.


 

Black Swallowwort Cynanchum louiseae or Vincetoxicum nigrum

Biological Control

None known.

Manual Control

Remove pod bearing plants and destroy them (burned or bagged and disposed in landfill). Complete root crown must be dug out before seeds ripen.

Mechanical Control

Mowing even several times a year will not eliminate, but will prevent seed crop if done early to mid-July. Plow under and plant annual crop until seed bank is exhausted > 5 years.

Chemical Control: Cut Stump

Apply 50-100% solution of herbicide concentrate (Roundup Pro ®, is more effective than Garlon® 4) immediately after cutting.

Chemical Control: Foliar spray

Cut just below the lowest pod, or mow in the summer, then spray re-growth August-September. Do not spray too soon in the spring or summer.


 

Autumn Olive Elaeagnus umbellata

Biological Control

None known.

Manual Control

Remove plants when they are large enough to grasp, but before they seed when ground is moist. Root fragments can re-sprout, be diligent about follow-up.

Mechanical Control

Cut at ground level or girdle, just when plants are flowering. Control re-sprouts in subsequent years.

Chemical Control: Cut Stump

Cut stem in August or September, immediately apply 50% glyphosate or triclopyr to at least 20% of the stem.

Basal bark method: Apply 25% triclopyr 75% horticultural oil solution from base of tree to 12-15 inches up when ground is not frozen.

Chemical Control: Foliar spray

Apply 2% glyphosate or triclopyr with 0.5% non-ionic surfactant.


 

Burning Bush Euonymus alatus

Biological Control

None known.

Manual Control

Plants can hand pulled and destroyed.

Mechanical Control

Repeated cutting to ground.

Chemical Control: Cut Stump

Cut to just above the ground and treat with glyphosate or triclopyr.

Chemical Control: Foliar spray

Apply glyphosate in the early summer months.


 

Yellow-flag Iris Iris pseudacorus

Biological Control

None known.

Manual Control

Hand-pull plant and rhizome system.

Mechanical Control

No effective methods.

Chemical Control: Cut Stump

Cut at round level and apply glyphosate.

Chemical Control: Foliar spray

No effective methods.

Notes/ comments

Identify when plant is in flower, as it is very similar to native Blue-flag Iris.


 

Japanese (vine) Honeysuckle Lonicera japonica

Biological Control

Grazing goats have been effective.

Manual Control

Prescribed burning prior to seed dispersal, late summer – early autumn. Hand pulling without disturbing soil too much. Must remove roots.

Mechanical Control

Repeated cutting once a year until no more re-growth.  Mowing mid-July and mid-September with chemical application DO NOT clip in winter, only makes plant come back stronger. Clip only in summer months. Cutting alone will not eliminate population.

Chemical Control: Cut Stump

25% glyphosate mid to late fall.

Chemical Control: Foliar spray

Seedlings 1% glyphosate, adult plants 2.5% solution w/ water and surfactant mid to late-fall. 2% solution of triclopyr.


 

Morrow’s Bush Honeysuckle Lonicera morrowii

Biological Control

Grazing goats have been effective.

Manual Control

Prescribed burning prior to seed dispersal, late summer – early autumn has been shown to be effective on large patches. Hand-pull individual plants ensuring full removal of roots.

Mechanical Control

Repeated cutting once a year until no more re-growth. Mowing mid-July and mid-September with chemical application. DO NOT clip in winter, only makes plant come back stronger. Cutting is not effective for elimination, can be means of control.

Chemical Control: Cut Stump

Apply 25% glyphosate summer, fall, winter (when not freezing). NOT effective treatment in spring.

Chemical Control: Foliar spray

Seedlings 1% glyphosate adult plants 2.5% solution w/ water and surfactant summer to mid-fall. 2% solution of triclopyr.


 

Purple Loosestrife   Lythrum salicaria

Biological Control

Insects are seen as most effective long term solution for large infestations: root-mining weevil (Hylobius transversovittatus), and two leaf-feeding beetles (Galerucella calmariensis and Galerucella pusilla). Two flower-feeding beetles (Nanophyes).

Manual Control

Patches of small number (<100), young (<2 years) plants may be pulled by hand prior to seed set.

Mechanical Control

Do not cut or mow, as they can reproduce vegetative.

Chemical Control: Cut Stump

Late in the season, cut 6 inches above the ground apply 20-30% glyphosate.

Chemical Control: Foliar spray

Apply 2% glyphosate in water plus 0.5% non-ionic surfactant as plants have begun flowering. Follow up for three years.

Notes/ comments

Planting native vegetation after removal deters new growth.


 

Common Reed Phragmites australis

Biological Control

None known.

Manual Control

Hand-pull small populations and individuals. Burn after plant has flowered, burning in spring or summer will stimulate growth.

Mechanical Control

Repeated mowing may be effective in controlling, but not eliminating. Cut below the lowest leaf. Material should be removed from site.

Chemical Control: Cut Stump

Glyphosate has been found most effective. Apply in late summer or early fall, after the plant has flowered.

Chemical Control: Foliar spray

Glyphosate has been found most effective. Apply in late summer or early fall, after the plant has flowered.

Notes/ comments

Cutting at times other than at the end of the growing season will stimulate growth. Restoring the flow of salt water to the site has been found to help eliminate plants.


 

Japanese Knotweed Polygonum cuspidatum

Biological Control

Shade the knotweed with other plants/ trees, as knotweed is highly light dependent and the shade will slow the growth.

Manual Control

Digging tools can be used to remove entire plant including roots and runners. All plant parts should be bagged or disposed of, as they can re-sprout.

Mechanical Control

Cut close to the ground for at least three times a year, for several years.

Chemical Control: Cut Stump

Cut stems about 2 inches above the ground and immediately treat with 25% glyphosate or triclopyr.

Chemical Control: Foliar spray

Apply 2% glyphosate or triclopyr in water w/ 0.5% non-ionic surfactant in late summer. Cut in late June, let re-grow, foliar spray w/ glyphosate after August 1.

Notes/ comments

Re-introduction of native plants should help to prevent re-colonize of the knotweed. All plant parts can re-sprout, be diligent about follow-up cutting, chemical applications, etc.


 

Common Buckthorn Rhamnus cathartica

Biological Control

None known.

Manual Control

Pulling of plants ensuring that the root stock is removed. 

Mechanical Control

Cutting of stems twice (June and August) repeated for 2 or 3 years. Girdling is effective by two parallel cuts deeper than the cambium and bark is removed.

Chemical Control: Cut Stump

Apply a 25% triclopyr solution to cut stump during summer and fall. Or apply a 20% glyphosate solution to cut stump in mid to late fall.

Chemical Control: Foliar spray

Apply 2-3% glyphosate solution in the spring.


 

Glossy Buckthorn Rhamnus frangula

Biological Control

None known.

Manual Control

Pulling of plants ensuring that the root stock is removed.

Mechanical Control

Cutting of stems twice (June and August) repeated for 2 or 3 years. Girdling is effective by two parallel cuts deeper than the cambium and bark is removed.

Chemical Control: Cut Stump

Apply 25% triclopyr solution to cut stump in the fall.

Chemical Control: Foliar spray

Apply 2-3% glyphosate solution in the spring.


 

Black Locust Robinia psuedoacacia

Biological Control

None known.

Manual Control

Pulling alone is ineffective at eliminating.

Mechanical Control

Cutting alone is ineffective at eliminating.

Chemical Control: Cut Stump

Cut then apply 6.25% glyphosate or 25% triclopyr solution in mid-summer. Follow up in a few years.

Chemical Control: Foliar spray

Triclopyr spray is effective when fully expanded leaves.


 

Multiflora Rose Rosa multiflora  and Rugosa Rose Rosa rugosa

Biological Control

A virus, Rose Rosette Disease (RRD), which is transmitted by a mite (Phyllocoptes fructiphilus), and the rose seed chalcid (Megastigmus aculeatus var. nigroflavus Hoffmeyer), a small wasp that lays eggs in and kills developing rose seeds. 

Manual Control

Hand removal difficult due to thorns and dense thickets.

Mechanical Control

Mowing or cutting 3-6 times a year for 2-4 years.

Chemical Control: Cut Stump

Apply glyphosate to cut stump.

Chemical Control: Foliar spray

Apply 1% glyphosate solution early summer (after flowering) till fall. Triclopyr can be applied before or during flowering.


 

Special notes:

Another method of chemical control, stem injection, is a method of injecting herbicide directly into the stem through use of special tools. Research has shown this method to be effective to control plants and prevent the release of the herbicide to unwanted areas.

Prescribed burning and livestock grazing has also been used in some areas as control methods. These methods would not be preferred due to the smaller acreage lots, with houses and neighbors relatively close by.

“Glyphosate products referred to in this fact sheet are sold under a variety of brand names (Accord®, Rodeo®, Roundup Pro® Concentrate) and in three concentrations (41.0, 50.2 and 53.8% active ingredient). Other glyphosate products sold at home improvement stores may be too dilute to obtain effective control. Triclopyr comes in two forms – triclopyr amine (e.g., Garlon® 3A, Brush-B-Gone®, Brush Killer®) and triclopyr ester (e.g., Garlon® 4, Pathfinder®, and Vinex®). Because Garlon® 3A is a water-soluble salt that can cause severe eye damage, it is imperative that you wear protective goggles to protect yourself from splashes. Garlon® 4 is soluble in oil or water, is highly volatile and can be extremely toxic to fish and aquatic invertebrates. It should not be used in or near water sources or wetlands and should only be applied under cool, calm conditions.” (Swearingen 2006)

This document does not endorse nor condone the use of these or other herbicides, or any treatment method, we are just presenting the latest information for you, the landowner, to make an informed decision.
 

Sources:

Cornell University Non-indigenous Plant Species Program: www.invasiveplants.net

invasives.org: Invasives.org is a joint project of The Bugwood Network, USDA Forest Service and USDA APHIS PPQ.

The University of Georgia: Warnell School of Forestry and Natural Resources and College of Agricultural and Environmental Sciences - Dept. of Entomology

Swearingen, Jil M., National Park Service, Washington, DC ©2006
“Weeds Gone Wild” - Alien Plant Invaders of Natural Areas

The Nature Conservancy: tncweeds.ucdavis.edu/handbook.html

UCONN Invasive Plant Management Guide (2001): www.hort.uconn.edu/cipwg/art_pubs/GUIDE/guideframe.html

University of New Hampshire Cooperative Extension: extension.unh.edu/forestry/Docs/invasive.pdf

Weeds Gone Wild: www.nps.gov/plants/alien
 

© 2008 Great Bay National Estuarine Research Reserve/USDA Forest Service


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