Invasive Exotic Plant Tutorial - Reed canary-grass MC

Species Management and Control Information

Reed canary-grass
Phalaris arundinacea L.

Source: The following information is taken from a number of sources and those sources are identified at the beginning of the referenced information. The intent of this resource is to provide the user with as much of the information that exists for management and control of this species as is practical. It is important to note that new and improved methods are added regularly which will require you to visit the websites provided for updates on this information. Bibliographies and resources referenced by these sources are not included here, but are included at the websites from which this information was extracted.

READ THIS FIRST!

Before administering any of the following management and control options, it is imperative that you are familiar with the background information provided under the General Management and Control Section.

For additional, and potentially more current, information on management and control of this species, use the Mid-Atlantic Exotic Pest Plant Council (MA-EPPC) listserve or any of the other listserves identified in the Resource - Listserve section of this tutorial. You will find directions for subscribing to the list serve there. The MA-EPPC listserve has an archives feature that saves past discussions (beginning in 1999) about specific species control. These messages are at: http://groups.yahoo.com/group/ma-eppc/messages.

GENERAL MANAGEMENT CONSIDERATIONS:

Delaware River Invasive Plant Partnership - Invasive Plant Fact Sheet - Reed canary-grass - http://www.paflora.org/DRIPP.html -Authors: Ann F. Rhoads and Timothy A. Block - April 2002.

Whatever means is used to eliminate reed canary-grass, it is essential to replant immediately with something that can out compete any residual plants or seeds, and retard erosion.

The Nature Conservancy - Invasive Species Initiative - Species Management Summary (ESA or Element Stewardship Abstract) - Phalaris arundinacea - http://tncweeds.ucdavis.edu/esadocs/phalarun.html - Author: Kelly E. Lyons - December 22, 1998.

As with most invasive species the best management strategy is prevention (Lesica, 1997). Control is difficult due to the rhizomatous nature of the species and may require herbicide treatment for several years. In addition, few herbicides may be used in wetlands or areas near running water, where reed canarygrass is usually most troublesome. When reed canarygrass is eliminated, there may be a danger of soil erosion if other species fail to cover the area quickly. Reed canarygrass is itself especially good at invading denuded areas and one way to prevent it from becoming established is to control erosion and replant eroded sites with competitive native species (Hoffman & Kearns, 1997).

Hutchison (1992) suggests that reed canarygrass should never be completely removed from a site because it is impossible to tell the difference between native and nonnative strains. If you determine that the plants are rapidly spreading, extremely competitive, and displacing many native species at a rapid rate, however, consider complete eradication as a goal.

A mixed management strategy may prove most successful for control of reed canarygrass. For example, Paveglio & Kilbride (1996) compared five different treatments: disking, mowing, early and late treatments with glyphosate herbicide, late glyphosate treatment alone, and early glyphosate treatment + disking. Glyphosate was applied as a 0.5% solution of Rodeo at 5.26L/ha (2.25 quarts/A) plus LI-700 surfactant. The early glyphosate treatment plus disking suppressed reed canarygrass and promoted the growth of other species. The early and late glyphosate application was also effective, providing 99% control in the first year.

The type of control chosen should depend on site characteristics. Where reed canarygrass is mixed with other species, burns or mechanical removal will be more effective as the area will be readily occupied by species that could potentially outcompete reed canarygrass and control erosion. Non-selective herbicides like glyphosate are most effective on sites that are totally dominated by reed canarygrass (Henderson 1987). Any patch left denuded is subject to erosion and re-invasion.

Wisconsin Department of Natural Resources - Invasive Plant Fact Sheets - http://www.dnr.state.wi.us/org/land/er/invasive/factsheets/reed.htm

Reed canary grass is difficult to eradicate; no single control method is universally applicable. In natural communities, mechanical control practices are recommended. In buffer areas and in severely disturbed sites, chemical and mechanical controls may be used. If herbicide is used, care should be taken to prevent contact with non-target species. Any control technique to reduce or eliminate reed canary grass should be followed by planting native species adapted to the site. As reed canary grass can enter a wetland area from eroding hillslopes, erosion control and catch-basins around a preserved wetlands are appropriate preventative measures.

MANUAL AND MECHANICAL CONTROL:

Delaware River Invasive Plant Partnership - Invasive Plant Fact Sheet - Reed canary-grass - http://www.paflora.org/DRIPP.html -Authors: Ann F. Rhoads and Timothy A. Block - April 2002.

Hand pulling is practical in small areas that are newly infested. Follow-up will be needed over 4-5 years, as fragments of rhizome will inevitably remain and grow. Mowing 5 times in a season has been found to be effective. Discing or plowing is another way to control reed canary-grass; however, many places where it is a problem are too wet for this to be practical. Flooding will kill the seeds, which cannot survive prolonged inundation, but established rhizomes are unaffected.

Illinois Nature Preserves Commission - Vegetation Management Guidelines - Reed Canary Grass - http://www.inhs.uiuc.edu/chf/outreach/VMG/rcanarygr.html - Vol.1, No. 19 - Author: Max Hutchison - February 6, 1990.

Hand removal for control may be feasible in small stands. There is evidence that hand chopping the culms at flowering time may kill small clones.

Ohio Department of Natural Resources - Division of Natural Areas and Preserves - Invasive Plant Fact Sheet # 6 - Reed canary-grass - http://www.dnr.state.oh.us/dnap/invasive/6canarygrass.htm - January 8, 2003

In smaller patches, hand-pulling or digging may be effective. Mowing can be used to control seed production by mowing in early to mid-June and early October before seed matures. This also exposes the soil to light which will promote the growth of other species. Discing or plowing can also be used to control a well-established population.

MECHANICAL: Removal of reed canarygrass by hand-pulling is practical only for small stands and requires a large time commitment (Hutchison, 1992). Henderson (1987) found hand-pulling was effective if done over the entire population 2-3 times per year for five years.

Hoffman and Kearns (1997) suggest covering reed canarygrass infestations with black plastic. They claim that for this method is to be successful, light levels should be reduced to less than 40% of normal intensity and the plants should not be allowed to grow beyond the plastic. (Shoots emerging beyond the edges of the covering will provide food to covered rhizomes.) Following successful control with black plastic, the area can be seeded with local, native species. However, this method was found to have little success by Apfelbaum & Sams (1987), who observed plants persisting even after two years under cover.

COMPETITIVE CROPS/RESTORATION: Native grasses and forbs are the best plants to use as competitors. Seeds can be collected and raked into the soil after reed canarygrass control. Competitive crop management has been most effective when used in conjunction with prescribed burning (Hutchison, 1992).

Desert saltgrass (Distichlis stricta) may be used as a "replacement species" in alkaline or saline soils where erosion may pose a problem after herbicide application and subsequent removal of reed canarygrass (Marquis et al., 1984). While native to the United States, desert saltgrass is found primarily in salt marshes and alkaline habitats (Hickman 1993) and may grow poorly outside of these habitats.

CUTTING: Cutting can effectively control reed canarygrass. Reed canarygrass was practically non-existent in fields after they had been cut five times in one season, even though the fields that had started out as roughly equal mixtures of reed canarygrass, Kentucky bluegrass (Poa pratensis), timothy (Phleum sp.) and mixed clovers (Trifolium spp.) (Wilkins and Hughs, 1932). If the plots were cut only twice during the season, reed canarygrass persisted.

DISCING/PLOWING: Reed canarygrass is quite sensitive to discing or plowing, and in some situations other plant species readily outcompete reed canarygrass afterwards. Paveglio and Kilbride (1996) found that an early season herbicide application (Rodeo at 5.26liters/ha) followed by discing three times late in the season suppressed reed canarygrass. The herbicide application prior to discing causes reed canarygrass rhizomes to deteriorate. Applying an herbicide prior to discing eases the task of discing and suppresses post-discing seedling emergence. Later applications of herbicide may be necessary to control seedlings.

ALTERATION OF WATER LEVELS: When wetlands have had their water levels lowered (for example, by ditching) restoration of original water levels may control reed canarygrass. Vegetative portions of reed canarygrass are generally regarded as intolerant of prolonged inundation (Hutchison, 1992) but some studies have found opposing results where rhizomes tolerate prolonged inundation (LeFor, 1987).

The seeds of reed canarygrass are generally short-lived when inundated. Long periods of inundation may serve to eliminate reed canarygrass seeds from soils. Comes et al. (1978) found most reed canarygrass seeds decomposed and/or germinated after only three months but germination rates of some seed remained high for 3-12 months after inundation. After 48 months of inundation, however, seeds of reed canarygrass no longer germinated.

Wisconsin Department of Natural Resources - Invasive Plant Fact Sheets - http://www.dnr.state.wi.us/org/land/er/invasive/factsheets/reed.htm

Small, discrete patches may be covered by black plastic for at least one growing season; the bare spot can then be reseeded with native species. This method is not always effective and must be monitored because rhizomes can spread beyond the edge of the plastic.

Mowing twice yearly (early to mid-June and again in early October) may help control reed canary grass by removing seed heads before the seed matures and exposing the ground to light, which promotes the growth of native wetland species. Discing the soil in combination with a mowing or burning regime may help by opening the soil to other species. Hand-pulling or digging may work on small stands in the early stages of invasion. Grazing can enhance diversity, although it will not control reed canary grass. A bulldozer can be used to remove reed canary grass and rhizomes (12-18" deep), after which native species should be seeded. Discing or plowing can also be employed in this manner.

In small areas with few natives, another method involves repeated cultivation for one full growing season followed by dormant seeding near the first-frost date. Disrupting the plant roots every two to three weeks weakens the remaining plants and depletes the seed bank. When combined with spot herbicide application in sections too wet for early or late cultivation, results after two years have been good. Frequent and continued cultivation is important since one or two cultivations would simply cut the roots up and increase the number of individual plants.

PRESCRIBED FIRE:

Delaware River Invasive Plant Partnership - Invasive Plant Fact Sheet - Reed canary-grass - http://www.paflora.org/DRIPP.html -Authors: Ann F. Rhoads and Timothy A. Block - April 2002.

Burning also works, however, timing is important; late spring or late fall are recommended.

RECOMMENDED PRACTICES IN NATURAL COMMUNITIES OF HIGH QUALITY: Fire can help control the spread of reed canary grass and keep it out of high quality wetlands. Repeated late autumn or late spring burning for several years can control this species. Annual burning may be needed for 5-6 years before good control is apparent. Burning is most effective where other species are present or in the seed bank, since fire allows native, fire-adapted species to compete successfully. Fire is not very effective in dense monocultures of this grass where seeds or plants of native species are absent.

Although prescribed burning can be effective, it must be repeated annually for 5 or 6 years. Timing may be difficult due to fluctuating water levels and the growth stage of the plants at burn time. A combination of these measures used together may improve results.

Fire is an effective form of control for reed canarygrass in highly productive wetlands. Some wetland species are unable to out-compete reed canarygrass without prescribed burning (Hutchison, 1992). Fire should be reserved for sites containing a healthy seed bank of fire-adapted native species that will readily colonize the area after a burn.

Apfelbaum & Sams (1987) describe a study that successfully contained reed canarygrass in low quality areas of a wetland using a two-year or three-year burn rotation cycle. Prescribed fire may be required for five or six years. The timing of burns is important. Henderson (1991) found that early spring burns accelerate the spread of reed canarygrass while late spring burns weakened reed canarygrass stands. Unfortunately, these late-season burns can harm other species. Late autumn burns are also beneficial.

Wisconsin Department of Natural Resources - Invasive Plant Fact Sheets - http://www.dnr.state.wi.us/org/land/er/invasive/factsheets/reed.htm

Prescribed burns in late spring or late fall may help reduce the reed canary grass population if repeated annually for 5 to 6 years. However, these fires are difficult to conduct due to water levels and/or the greenness of the grass at the time of burning. The application of 1.5% active ingredient solution of glyphosate will "brown off" reed canary grass enough to conduct prescribed burns. Burning is also ineffective in dense stands of reed canary grass that lack competition from native, fire-adapted species in the seed bank. A late-spring burn followed by mowing or wick-applying glyphosate to the emerging flowering shoots will eliminate reed canary grass seed production for that year.

GRAZING:

Grazing may be effective means for controlling reed canarygrass but the palatability of reed canarygrass is questionable--the genus Phalaris is notoriously unpalatable and an illness associated with the affects of consumption is called 'Phalaris staggers' (Marten et al., 1976). Grazing can also be inappropriate in wetland settings (Hutchison, 1992). However, Haslam (1973) suggests employing wetland meadows for the production of "marsh hay." Ponies are preferable grazers as they are more agile in waterlogged soils and may be left unattended while cattle and sheep may get stuck in the mud and perish.

Palatability decreases with plant maturity (Marten et al., 1976; Gomm, 1979) and continuous grazing may decrease palatability. Plants' chemical and physical defenses may be induced by herbivory, but cutting often fails to elicit the same defensive response (Agrawal, 1998). The literature does not address the response of reed canarygrass alkaloid concentrations in response to grazing.

BIOCONTROL:

Delaware River Invasive Plant Partnership - Invasive Plant Fact Sheet - Reed canary-grass - http://www.paflora.org/DRIPP.html -Authors: Ann F. Rhoads and Timothy A. Block - April 2002.

No biological control options are currently known.

There are currently no biological control methods in use for reed canary grass.

CHEMICAL CONTROL*:

Delaware River Invasive Plant Partnership - Invasive Plant Fact Sheet - Reed canary-grass - http://www.paflora.org/DRIPP.html -Authors: Ann F. Rhoads and Timothy A. Block - April 2002.

Glyphosate will control reed canary-grass; but, because it often grows in or near water, only formulations approved for aquatic use (Rodeo) should be utilized.

Illinois Nature Preserves Commission - Vegetation Management Guidelines - Reed canary-grass - http://www.inhs.uiuc.edu/chf/outreach/VMG/rcanarygr.html - Vol.1, No. 19 - Author: Max Hutchison - February 6, 1990.

RECOMMENDED PRACTICES IN BUFFER AND SEVERELY DISTURBED SITES: Certain herbicides are effective where there is no real concern for damage to surrounding native species. Rodeo, a formulation of glyphosate designed for use in wetlands, will kill reed canary grass, especially young plants, when applied to foliage according to label recommendations. Rodeo should be applied in early spring when reed canary grass is green and most native wetland species are still dormant. The area should be checked after spraying, and any surviving reed canary grass should be sprayed the following spring. Dalapon and Amitrol also reportedly kill canary grass, although no Illinois natural area managers were found that have experience with these herbicides. All 3 herbicides are licensed for use in aquatic areas. Rodeo and Amitrol are nonselective herbicides that will kill all vegetation contacted. Dalapon selectively kills grasses and monocots, but not broadleaf plants. Spraying foliage with Roundup (a formulation of glyphosate) mixed according to label instructions and subsequent burning of dead residue has been moderately effective in northern Illinois. However, Roundup is not licensed for use in aquatic areas and should only be used in areas without standing water. When using any herbicide, precautions should be taken to avoid contacting nontarget species. Do not spray so heavily that herbicide drips off the target species. The herbicide should be applied while backing away from the treated area to avoid contacting wet herbicide. By law, herbicides only may be applied as per label instructions and by licensed herbicide applicators or operators when working on public properties. Where practical, it can be useful to sow in seed of nearby native grasses and forbs after reed canary grass has died (due to control efforts) or gone dormant. Seed of nearby native grasses and forbs should be collected when ripe and then raked into the sod as soon as the reed canary grass has died.

Ohio Department of Natural Resources - Division of Natural Areas and Preserves - Invasive Plant Fact Sheet #6 - Reed canary-grass - http://www.dnr.state.oh.us/dnap/invasive/6canarygrass.htm - January 8, 2003

Herbicides, such as Accord® or Glypro®, can be applied to control reed canary grass. Fusilade DX®, a grass specific herbicide, can be applied in non-wetland areas. Herbicide should be applied in early spring when nontarget species are still dormant. Removal of the previous year's growth to expose the new green shoots aids effectiveness of the chemical and minimizes the amount needed. Foliar application of Glypro® to larger monocultures of reed canary grass can be effective. Chemical treatments following mowing in the fall season can help control this grass as well.

Several herbicides have been tested and proven effective for controlling reed canarygrass. The most effective include glyphosate and fluazifop butyl. When applying herbicides, take precautions to avoid contact with non-target species.

In general, reed canarygrass is more effectively controlled by herbicides on upland, drier areas of a site (Hodgson, 1968). In one experiment, upper areas on a canal ditch had 100% control while in the lower, wetter areas only 50% of the reed canarygrass was removed. Bruns (1973) was also unable to kill all shoots at the waterline. This was due to dilution of the herbicide when applied at or near the water and removal of the herbicide from the soil by water.

Reed canarygrass is rarely fully eradicated and yearly, or even monthly, attention to the control of this weed is necessary. Hodgson (1968) found consecutive, yearly treatments were required to control reed canarygrass. Hoffman & Kearns (1997) suggest that old vegetation be removed before herbicides are applied to ensure that the herbicide contacts new growth. Where large populations of reed canarygrass are eliminated, seeds of other species should be sown to increase competition with resprouts and prevent erosion.

FLUAZIFOP-D (FUSILADE, HORIZON)
Apply fluazifop at 0.28-0.42 kg ai/ha (0.25-0.375lb ai/A) (1 to 1.5 pint product/A) to actively growing reed canarygrass with 1% v/v crop oil concentrate or 0.25% v/v nonionic surfactant. Fluazifop acts very slowly (2-4 weeks before results are seen). Do not apply to stressed grasses. If regrowth occurs, repeat application. Do not use crop oil concentrate if treating reed canarygrass ornamentals. Do not apply if rainfall is expected within 1 hour (William et al., 1997).

GLYPHOSATE (RODEO OR ROUNDUP)
Rodeo is a formulation of glyphosate that is specifically designed for use in aquatic habitats. It will kill reed canarygrass if applied to young plants according to the manufacturer's directions. It should be applied in early spring when reed canarygrass is just sprouting and before other wetland species germinate. Rodeo is nonselective and should be applied only in areas where damage to other species is unlikely (Hutchison, 1992). Roundup is not registered for use in aquatic areas and is designed for use only where there is no standing water. Rodeo and Roundup (1.4 to 2.8 kg ai/ha; 1.2 to 2.25 lb ai/A) should be applied to actively growing plants at early heading or in the fall. Follow the manufacturer's instructions regarding surfactants (William et al., 1997).
An application of Roundup according to the manufacturer's recommendations and combined with the burning of dead residue was moderately effective in Illinois (Hutchison, 1992).
In Prosser, Washington, glyphosate was applied to seedlings of three species (reed canarygrass, red top and creeping fescue) at three, five, seven, and ten weeks post-emergence and to 15 month old plants in the spring. Applied at 1.1 kg/ha, a decrease in reed canarygrass at all age stages was observed without causing much damage to red top and fescue. For 15 month old plants, glyphosate applied at 2.2 kg/ha yielded up to 95% control (Comes, 1976). · At TNC's Middle Fork John Day preserves, Roundup was reported to be an effective control measure at high concentrations (Youtie, personal communication).

SULFOMETURON (OUST)
Apply at 26-43 g ai/ha (3 to 5 oz product/A) to preemergent or early postemergent plants. Oust is labelled for use on non-cropland only. Do not apply to frozen ground. Maintain constant agitation while mixing in spray solutions. Add 0.25% v/v nonionic surfactant to increase the activity of postemergence applications. Powder, dry soils and light, sandy soils should not be treated when there is little likelihood of rainfall after treatment (William et al., 1997).

Wisconsin Department of Natural Resources - Invasive Plant Fact Sheets - http://www.dnr.state.wi.us/org/land/er/invasive/factsheets/reed.htm

Small, scattered clones (2 feet in diameter) can be controlled by tying the stems together just before flowering, cutting them, and applying glyphosate in a 33% active ingredient (a.i.) solution to cut stems.

A formulation of glyphosate designed for use in wetlands will kill reed canary grass (especially young plants) when applied to foliage. Apply in early spring when most native plant species are dormant. Any herbicide application should be done only after removing dead leaves from the previous year in order to maximize growing shoot exposure and to minimize herbicide use. A 5% a.i. solution of glyphosate formulated for use over water applied as a foliar spray will kill reed canary grass. Two herbicidal applications may be necessary to ensure complete coverage. Herbicide applied with a wick applicator attached to a tractor affects taller stands of reed canary grass without impacting the shorter vegetation.

A late mowing in mid-September, followed by the application of 5% glyphosate a.i. in October (after big bluestem is dormant) can help to control reed canary grass.

Because reed canary grass productivity is reduced by shade, planting native shrubs or wetland trees in areas of chemically-treated grass may be effective.

While herbicide kills reed canary grass, the seed bank may germinate and recolonize the site. Several herbicidal application may be necessary to inhibit seed bank recolonization. After the first application of herbicide has killed living plants, disturbance of the soil can encourage seed bank germination. When this occurs, the site can again be treated with herbicide to deplete the seed bank.

An alternative method involves wick application of glyphosate in the first to third weeks of June, followed by a late June to mid-July burn. This technique reduces reed canary grass cover, depletes the seed bank, and stimulates native seed banks.

In non-aquatic environments, DalponTM and Trichloracetic (TCA)TM effectively treat reed canary grass when applied in late fall or early winter. Both are soil sterilizing herbicides that must be sprayed on dried foliage in a rate of 20 to 40 lbs. per acre. Aquatic systems may also be treated with DalponTM for control up to two years. DalponTM is weakly cationic and is not absorbed by substrates the way most herbicides are.

* Mention of pesticide products in this document does not constitute endorsement of any particular material.

OTHER CONSIDERATIONS:

Illinois Nature Preserves Commission - Vegetation Management Guidelines - Reed Canary-grass - http://www.inhs.uiuc.edu/chf/outreach/VMG/rcanarygr.html - Vol.1, No. 19 - Author: Max Hutchison - February 6, 1990.

FAILED OR INEFFECTIVE PRACTICES:

The Nature Conservancy - Invasive Species Initiative - Reed canarygrass: Control and Management in the Pacific Northwest - http://tncweeds.ucdavis.edu/esadocs/phalarun.html - Author: Mandy Tu - June 7, 2004.

Control Summary
There is no immediate one-year "fix" to convert a RCG infestation into a native community, but much can be accomplished within 2 to 3 years. Continued monitoring and follow-up treatments will be required for up to 5 to 10 years to prevent reinvasion. Reed canarygrass is difficult to control due to its persistent rhizome system and its ability to reproduce both vegetatively and sexually. However, depending on available time and resources, even highly infested areas can be restored to more desirable vegetation. Be sure to use an adaptive management process to determine your management objectives, to develop your work plan, and to be able to continually update that plan as results of your management actions become apparent. The successful restoration of your wetland system from RCG will likely involve five steps:
1. The control/removal/kill/local eradication of the existing RCG plants and rhizome system.
2. Exhausting the RCG seed bank.
3. Depending on how long the RCG infestation has been in your site, active restoration (replanting or reseeding of desirable vegetation) may be required. If your RCG infestation has not been at that site for over 5 to 10 years, there may be enough of a remnant native seedbank to allow passive restoration.
4. Prevention of new seeds or stem fragments from entering your managed area, and/or changing those conditions that facilitated RCG invasion in the first place.
5. Finally, continued monitoring and follow-up treatments are necessary for lasting results.

There are a variety of methods available for the control of RCG. Which method or combination of methods you choose will depend ultimately on your management goals and objectives (are you trying to fully restore a Puget Sound wetland or just add structural diversity to a Willamette Valley riverbank?). Also, how many resources you are willing to invest and for how long, what resources do you already have available, and the size, distribution, and location of your RCG infestation will all determine which option you should choose to manage RCG. Unless you only have a few small isolated patches, the long-term successful management and control of RCG will require a multi-year commitment.

Prevention
Prevention of new invasions is the most efficient and cost effective method of invasive species management and control, and the prevention of new RCG infestations are no exception to this rule. Maintaining a healthy community of native or otherwise desirable plants, taking care to not disperse RCG seed or propagules, and carefully monitoring your managed area periodically (especially along roadside ditches and other disturbed areas) and eradicating small RCG populations as soon as possible and in neighboring lands can greatly benefit your RCG management efforts. Another prevention method is to work to change those environmental conditions that allowed RCG invasion in the first place. Recent research completed from Wisconsin and Minnesota have shown that when levels of available soil nutrients (namely nitrogen) are reduced via carbon enrichment, a native sedge, Carex hystericina, is able to competitively suppress the growth of RCG. Sustaining a mosaic of microtopographies (by preventing sediment accumulation) facilitates native species richness, and maintaining complex herbaceous canopies also work to prevent RCG infestation, since RCG seed germination is dependent on amounts of light penetration.

Manual & mechanical methods
Digging: Isolated plants or small patches of RCG can successfully be removed by digging out and removing the entire root mass. Removal is easiest when the soil is moist. Be sure to remove all rhizomes and roots, as small rhizome fragments can resprout. Properly dispose of plant material, since rhizomes and stems can develop new roots if inundated, or if kept in contact with moist ground. Be sure to follow-up to catch any resprouted stems.

Mowing/Cutting: Mowing or cutting (using a mower, brush cutter, weed eater, tractor-drawn mower, machete, etc.) by itself will not kill RCG. In fact, if RCG is mowed only once or twice per year, it actually stimulates additional stem production. Continued mowing (5x or more per year) for 5 to 10 years is reported as successful in controlling RCG, but this has not been demonstrated on a large scale in the PNW. Mowing can be used in combination with another control method, such as followed by a herbicide application, for good control. Additionally, mowing prior to or at the onset of flowering can eliminate seed set for that year. So, you can choose to mow RCG for several years to eliminate the seed bank, and then a final mow followed by herbicide application to eliminate mature RCG. Mowing can also facilitate the installation of shade cloth, or be used as a pre-treatment for tillage, since it will remove or break up the thick layer of dead litter.

Tillage/Cultivation: The use of large tillage machinery can successfully eliminate RCG if combined with a proper flooding regime. The USFWS Refuges at Ridgefield (near Vancouver, WA) and Finley (near Corvallis, OR) have successfully used a combination of tillage + flooding to convert large RCG infestations into native wetland habitats. This method, however, requires the use of large, expensive equipment,and requires the ability to manipulate water levels. Additionally, use of tillage to manage RCG assumes that you have no species or communities of concern that you are trying to preserve at the site. If you are working in a sensitive area or in a relatively intact native system, this may not be a viable option. The purchase of the large tillage equipment (48-inch tillage plates and tractor) can be prohibitively expensive, but it may be available locally for rental or borrowing. To eliminate large, dense RCG infestations using tillage + flooding, you should till through the RCG sod layer as soon as it is possible in the field season (usually, as soon as it is dry enough). The initial tillage may require several passes of the equipment, since the RCG sod layer may be thick and tough. Let the exposed stems and rhizomes dry-out. You will need to till several times during the field season to break-up and dry all rhizome fragments (until you have nothing left but broken-up clods of soil). Finally, when the winter flooding begins, close floodgates and keep the entire area inundated at least 18 inches deep through late spring (late May-June) the following year. This combination of methods will eliminate large infestations of RCG, but follow-up (i.e. spot herbicide treatment with a backpack sprayer) will still be required for several years, since some RCG plants will survive or will reinvade the site. Active restoration will be necessary if a remnant seed bank does not exist.

Flooding without tillage: Controlling the hydrology of the site to lengthen the time an area spends totally submerged may be a viable control strategy if you have control over the hydroperiod of your site. Local experiments are underway using this technique by the USFWS at the Sandy River Delta and by the Port of Portland at the Vanport wetlands along the Columbia River. Other treatments will be necessary along the edges of the flooded zone.

Prescribed Fire
Burning generally does not kill mature RCG, and similar to occasional mowing, actually appears to stimulate additional stem production unless the fire burns through the entire RCG sod layer down to the mineral soil (which in turn, may create other problems). In most cases, RCG remains green long into the season, and so does not burn very hot. In the PNW, prescribed fire can only occur in the fall, and burning RCG in fall does little to control it. Herbicide treatment prior to burning can facilitate a prescribed fire, especially outside of typical "fire seasons." Prescribed fire can however, be used as a pretreatment to tillage, shade cloth, or prior to herbicide application for good results, since the fire will remove the aboveground dead litter and standing vegetation. Burning for several years in a row is generally not possible because of lack of fine fuels after the first-year burn.

Solarization, Shade Cloth, & Mulching:
Solarization (essentially baking under clear or black plastic) or the use of a thick woven geotextile shade cloth can be used to eliminate RCG. In dense areas of patchy RCG growth this method can provide specific, targeted control photograph 8). In areas where RCG is mixed-in with desirable species, the kill of those desirable species may or may not be an option. Also, the use of certain materials for this method depends on your overall management goals. There are reports from the Puget Sound region of good RCG control by using several layers of cardboard covered by 4 to 6 inches of wood mulch. The addition of these materials into your site may or may not be acceptable. Excellent control of RCG can also be accomplished by using a thick woven plastic fabric (Mirafi(r) or Amoco(r) brands), held in place by 7-inch gutter spikes and washers and duck-bill tree anchors. The fabric is kept in place for over one year (over an entire growing season), even under inundation. This method will kill all plants under the cloth. Revegetation or reseeding is generally necessary with this method. Shade cloth is initially expensive (approximately $400 per 12 ft x 350 ft roll), but can be reused several times, and this method does not require follow-up visits during treatment. Mowing prior to the installation of shade cloths greatly facilitates installation. Small patches can likely be treated using black plastic bags, if they are kept in place for the entire duration, the edges are tacked-down firmly, and the bags do not shred.

Grazing
Grazing alone does not control RCG. It is likely that much of the RCG present in the PNW today comes from European cultivars planted purposefully for pasture, so grazing has little to no negative impact on the growth and survivorship of RCG. Cattle prefer RCG when stems and leaves are young and succulent, but do not prefer it once stems become old and tough. Goats and sheep will graze on RCG. Grazing can be combined with another treatment method (followed by tillage, herbicide, shade cloth), for good control.

Chemical Control Methods
RCG can be successfully controlled by the proper use of herbicide. Small stands or clumps of RCG can be effectively killed with one application, but large infestations will likely require several applications over several years to be effective. Since RCG frequently grows in wet areas, only aquaticapproved herbicides are allowed in many situations. As with all herbicide use, be sure to read and follow all label instructions and to abide by all state regulations. Glyphosate (Rodeo(r), Aquamaster(r), or Glypro(r) among others) applied in a 2% solution (1.08% active ingredient (a.i.)) with a nonionic surfactant works well to kill RCG. Glyphosate is a non-selective herbicide that kills or injures nearly all plant species. Glyphosate is also available in many other formulations (e.g. RoundUp(r)). These work well to kill RCG, but are not labeled for aquatic use, so be aware of the areas where you plan on applying herbicide. Sethoxydim (Vantage(r)) is a grass-specific herbicide that has been used to kill RCG with some success in the PNW, but it is also not labeled for aquatic use.

Always follow all herbicide label instructions and directions! Non-target organisms that come in contact with the herbicide may be injured or killed. If you have questions about herbicide choice or whether your use is legal, please contact your state Department of Agriculture or local extension agent. Depending on the size and distribution of your infestation, the herbicide can be foliar-applied using a dripless wick applicator, backpack sprayer, or boom sprayer (please visit http://tncweeds.ucdavis.edu for a full discussion of herbicide application tools). Herbicide should be applied to foliage during the growing season. Application in the PNW can occur in mid-summer (just prior to summertime dormancy) or preferably in late fall (just prior to frost and wintertime dieback). It is recommended to apply herbicide at these times, since it is speculated that these are the times of year when RCG is most actively translocating carbohydrates (along with the herbicide) down into the root system.

You may also combine an herbicide treatment with another control treatment for good results. First, eliminate the aboveground dead litter by mowing or burning, then allow the RCG stems and leaves to regrow to boot height. This helps obtain better herbicide coverage and reduce total herbicide use, since you are spraying only living green RCG that is 12" tall vs. 6' tall stems mixed with old dead leaves. Follow-up monitoring and treatment is necessary for several years to ensure complete kill.

Restoration/Competition
Planting fast-growing shrubs or trees may eventually eliminate RCG since it is intolerant of year-round shade, but depending on your management goals and objectives, this may not be a viable option. In the Puget Sound region where forested wetlands are common, planting native evergreen trees (Pseudotsuga menziesii, Picea sitchensis) may be desirable and can successfully shade-out and eliminate RCG. One way to add conifers into a RCG dominated system is to cut holes into large downed woody debris, and plant the conifer seedling into that hole. If planting trees directly into the RCG wetland, the trees will do better if the RCG is kept mowed, or if the trees are planted on top of soil mounds.

In the Willamette Valley however, native wet prairies did not have a large conifer component, and the addition of coniferous trees into this system may be undesirable. Because RCG can survive under the deciduous canopy of cottonwoods (Populus trichocarpa) and Oregon ash (Fraxinus latifolia), the planting of these trees and other native shrubs alone (Spiraea douglasii, Sambucus racemosa) are not be likely to be successful at fully eliminating RCG. However, the City of Portland Bureau of Environmental Services reports success with planting high-density cottonwood or alder. Where they have reached a closed canopy by year five, they report almost near eradication of RCG. While this is not true eradication, it is enough to allow success in moving the site into an artificial conifer succession stage and to try to establish some native forbs. Creating a dense herb layer may be able to exclude RCG, once it is firmly established. Native grasses, sedges and rushes such as Beckmannia syzigachne, Eleocharis palustris, Carex densa, C. feta, C. unilateris, Juncus oxymeris, Deschampsia caespitosa, and Agrostis exarata, along with a native forb component (Myosotis laxa, Plagiobothrys figuratus, Veronica scutellata) may work to exclude RCG in some situations in the Willamette Valley. Further, a complex herbaceous canopy can work to prevent RCG seed germination.

The likeliest scenario for successful exclusion of RCG using native species is habitats that are marginalfor RCG in the first place, i.e. those that are submerged for much of the year. In the transitional zone between the emergent plant community and the upland, where we find the most difficulty with RCG in the Portland Metro region, native sedges, grasses and other emergent species have difficulty in holding their own against RCG. The City of Portland Bureau of Environmental Services suggests those areas are most easily managed by planting either one of the two following strategies:

1) live stakes- living branch sections from adapted trees/shrubs like willow, dogwood
2) shrub clusters- first scalp the sod off the top of an area about 5' by 3', then plant a cluster of shrubs- we generally use 10 for each cluster, then mulch well with a coarse grained mulch which will keep RCG from coming up from the bottom but also prevent broadleaf weed invasion from the top.

Best Management Practice Recommendation
The best management approach to use will depend on your overall management goals and objectives, the size, distribution and location of your RCG infestation(s), your capability and willingness to use herbicides (or not), and your available resources (staff and volunteer time, money, equipment, etc). The following recommendations are not necessarily the best management methods for every situation, nor are they presented in an order of preference. The methods listed below have however, been used with some success in the PNW. Also, every method will require follow-up monitoring and treatment (including replanting native species if necessary) to ensure the long-term success of your treatments.

Scattered individual plants or small patches in healthy native vegetation
1. Dig out using a shovel
2. Spot-spray or wick with herbicide
3. Spot flame with a propane torch (only works for seedlings or young individuals)

Distinct patches of RCG within a matrix of native vegetation
1. Dig out using a shovel (depends on size)
2. Cover with shade cloth (may be preceded by mowing)
3. Mow (to eliminate seeds), then spot-spray or wick with herbicide
4. Spot-spray or wick with herbicide

Large patches (up to several acres) of RCG with scattered native vegetation (Which method you choose will depend on how much you want to keep your native vegetation)
1. Mow then cover with shade cloth
2. Mow then herbicide (wick, spot-spray or boom)
3. Herbicide using appropriate application technique
4. Spot-burn then spot-spray regrowth
5. Cover with shade cloth (may be preceded by a mow treatment)

Large (hundreds of acres) monocultures of RCG
1. Mow using large mower, herbicide spray using boom sprayer
2. Prescribed burn, then herbicide spray using boom sprayer
3. Tillage and flooding