Integrated Pest Management (IPM) Guide for Common Weeds

Integrated Pest Management (IPM) Guide for Common Weeds Western Invasives Network – Revised February 17, 2015 Disclaimer: This document is a basic guide and assumes no liability toward product efficacy, loss of non-targeted plants, or personal safety issues. Always follow label instructions, wear proper safety gear, and avoid herbicide drift. If in doubt as to control practices, consult a licensed treatment contractor. Please refer to the PNW Weed Management Handbook for specific herbicide recommendations: http://uspest.org/pnw/weeds/.

Species Mechanical Chemical IPM Notes/Tips - Mow at least twice a -Treat with Crossbow or - Mow in June and - A rust that stunts year: June and Garlon 3A in fall, usually allow for regrowth, blackberry growth September. in September/October. then spray in fall. was accidentally Garlon 4/Escort combo introduced to the - For small patches, grub can be an effective mix - A cut stump U.S. and is active in roots in the winter through and offers a longer treatment works well, SW Oregon. early summer when soil is treatment window. and prevents moist. Be sure to remove overspray and drift. Its impact appears to Armenian root collar. Glyphosate in the fall, Cut the stem next to be dependent on (Himalayan) when the first few yellow the ground and, using local climate (dry Blackberry -Other than for the leaves show up, is also a brush, sponge, or weather is not Rubus European blackberry, effective, and suitable for small spray bottle, conducive to the armeniacus shading is a good long- wet areas if using aquatic apply a 50% solution rust). term non-chemical versions. of glyphosate and Evergreen approach to blackberry water immediately to ). (New data Blackberry control - In mixed stands of the cut stem. suggests multiple Rubus blackberries and species of discolour - Repeated mowing or snowberries (common in blackberry in NW, disking can also be riparian areas) you can with rust only effective spray over the top of both effective on 2 or 3) in the fall using Garlon 3A European and MSO surfactant Blackberry without any ill effect on Re-seed area with Rubus snowberries. native grasses, fruiticosus trees, and shrubs. Silicone/ organosilicone spreader surfactant such - Be persistent! New as Sylgard or Freeway vines are always ensure excellent coverage showing up. and reduces overall herbicide use; however silicon based surfactants Graze with goats. may damage non-target plants.

Species Mechanical Chemical IPM Notes/Tips Scotch - Cutting large plants (stem - If possible, spray Scotch - Mow in early spring. -- Don’t mow Scotch Broom greater than 1/2 inch) broom before and after broom when seed below the crown can be bloom, as the flowers -Treat regrowth in fall pods are ripe. French effective without herbicides intercept the herbicide or the following spring Broom in Aug. - Sept. when they with Garlon, Milestone - Pulling large plants are stressed from drought - Water stress in late VM Plus or Crossbow. with a weed wrench Portuguese summer can cause creates ideal Broom - Pull smaller plants (less reduced herbicide - You can also use growing conditions than 1/2 inch) by hand or effectiveness. glyphosate (Round for seed bank so with a weed wrench. Up) for early fall consider cutting - Garlon 3A or 4, treatments, though instead. - Mowing is sometimes glyphosate, and results may be done to knock down large Crossbow are all marginal on thicker - Seed treatment Scotch broom patches, but effective. stems. Application will area heavily with should be avoided when kill non-target grass to shade out seed pods are ripe. There - Garlon 3A and Milestone vegetation. Scotch broom is a good chance that mixed are very effective seedlings. seeds already on the and don’t require - In dry settings, cut ground will be spread by complete coverage of stumps often don’t - Calibrate sprayer mowing. plant for total control. need herbicide well and watch your treatment if they are rates. - Biocontrol seed beetles - Silicone/ organosilicone an inch in diameter or and weevils, may provide spreader surfactant such bigger. Late summer Early season a measure of control by as Sylgard or Freeway cutting below crown is mowing typically feeding on seeds. They ensure excellent coverage advised. results in dense, are readily available and and reduces overall multi-stemmed widespread. Collect and herbicide use Be careful regrowth; great for release in April to May. of surrounding vegetation! spraying

Species Mechanical Chemical IPM Notes/Tips - IMPORTANT: Mow - IMPORTANT: Spring - Introduce goats with - There may be a before seed formation. application is critical. other grazers. Goats biocontrol agent Apply herbicides prefer broad leaved already present! - Except for Canada BEFORE plants flower. plants. Don’t over thistle, hand digging or graze. - No tansy ragwort pulling is feasible for small - The following herbicides biocontrols? Don’t infestations. are effective: 2, 4-D, - If you miss spring panic - the bugs will Weedmaster, Garlon 3A, spray time, you can come! Biocontrol - Cut and bag all seed Curtail, Opensight, mow in early summer agents cycle with the Pasture heads, and burn or Stinger, and Milestone. and spray in the fall. plant population and Weeds dispose of them to prevent This approach works will become more (broad-leaf spread of seeds. - Stinger and Curtail are well for Canada thistle abundant and weeds in effective on Canada and tansy. effective as tansy grass thistle when plants are becomes more pasturage) short (less that 6”) to full - Keep pasture grass abundant. height. Glyphosate is competitive by Includes: only effective when plants maintaining high - Cut, bag and tansy ragwort, are in late bud to flower fertility. dispose of tansy teasel, stage or on fall regrowth. ragwort and teasel thistles, dock, seed heads. St. John's - If you want to save wort, et al) clover, use MCPA. All Don’t use manure others will eliminate derived from clovers. clopyralid treated pasture or hay in gardens or organic operations. These compounds persist in the manure.

Species Mechanical Chemical IPM Notes/Tips English Ivy - Protect trees and prevent -The current hot ticket: - Cut ivy away from - If you do nothing seed production by cutting 4% Accord Concentrate trees and apply foliar else, keep ivy out of vines around tree trunks. (glyphosate)] + 2% Garlon herbicide treatment to the trees to keep Clear ivy three feet out 3A (triclopyr amine) + 2% leaves on the ground. seed production from the base of the tree. Competitor (modified lower. vegetable oil (MSO) - Cut ivy trunks back - Using rakes and shovels surfactant. to ground and paint or - Cut the climbing vines can be pulled and spot spray them with vines, taking a good rolled down a slope like a 25% glyphosate or Garlon. chunk out of them so carpet. triclopyr for cut stump they don’t grow back Weed whacking and together. This also - Goats and sheep LOVE - If possible, apply during applying herbicide to ensures you don’t ivy, and can be used to dry periods in late winter new growth can also miss any of the clear areas prior to pulling or early spring before be effective. small vines that of the roots. native plants leaf out or might be mixed in emerge. hidden in the larger ones. - You will not notice effects until weeks, if not months later, so be patient!

Species Mechanical Chemical IPM Notes/Tips - Burn ‘em out - apply early - A wide range of - Pull/hoe when you - Control early and season flaming. herbicide products can be can; if things get monitor it often as used to initially control the away from you, apply seasonal annuals - Hand pull large weeds vegetation. herbicides. sprout at different early in season before times of the year seed set. - Smothering with and new species are Pre-emergent herbicides fresh gravel over a introduced. - Apply fresh gravel on a that are effective, residual treatment regular basis. products containing: helps sustain longer oryzalin, benefin, or control. Parking lot trifluralin will provide weeds partial control of (puncture germinating seeds. These vine, prostrate must be applied prior to knotweed, germination (late winter to et al) mid-spring).

Post emergent), products containing 2,4-D, glyphosate, and Dicamba are effective on puncture vine, especially when small.

Species Mechanical Chemical IPM Notes/Tips - Broadcast application of - To reduce the - False brome is a glyphosate-based amount of herbicide spreading fast. Slow herbicide such as used, mow for several the spread by Roundup, is effective in years to eliminate soil making sure clothing . - Mowing can be used to mid May through fall. seed bank. Then treat and equipment are remove/deplete annual with herbicide. free of seeds before seed production Optimal - OSU field trials suggest you leave an mowing for this purpose is tank mixing glyphosate Also, burning infested site. June (plants will still flower (2%) with a followed by spot- when mowed earlier). preemergent herbicide spraying after the - Put up False Brome such as Surflan (3.3%) grass resprouts can informational signs applied in October. This minimize the amount at trailheads to urge - Hand pulling small kills mature plants AND of herbicide needed hikers to clean patches is best in April and stops seeds from clothes, pets, and early May. germinating. - You can also mow in OHVs. June, and then treat -Mulching with clean, weed - Apply herbicides in fall with Roundup in the free straw works well to after first rains, as that is fall. suppress false brome for when the plants start at least two years growing again

Species Mechanical/Manual Chemical IPM Notes/Tips Garlic - Mowing is not an Most important time to Combination of spring Mustard effective control because spray is in early spring herbicide application Ideally, this plant plants will still bolt and (typically early April-late followed by hand should be addressed seed May) during bolting or pulling is very 3 times yearly, early flowering. effective. spring application, hand pulling, fall Rosettes can be sprayed Spray bolting and application in early fall after rain early flowering plants events end summer in early spring Multiple years are dormancy but before (typically early April- needed to exhaust leaves begin to fall from late May). Revisit seed bank, which trees and cover garlic sprayed sites in early can last up to 8 mustard plants June (once seeds are years. formed and spraying Rosettes can also be has become Spray before the sprayed in late winter, but ineffective) to hand plant goes to seed! this is only effective after pull any plants that Once seed passes winter dormancy ends. were missed or bolted early seed set (milk Garlic mustard often dies after spraying. into dough stage) it - Mowing spreads garlic back in the winter so you will still be viable if mustard seed like wildfire - must wait until the great Pulled plants must be sprayed. do not mow when seed majority of plants have re- bagged and removed pods are present (May - sprouted. from the site. Consider impact of Sept.) crews – clean boots, Rosette treatments at the Revisit sites if possible clothing, and - Hand pulling is easiest height of summer may be after initial pull and be machinery before during early bolt (2nd year). least effective due to prepared to repeat moving from areas Difficult during rosette summer dormancy pulling if smaller or with garlic mustard stage (first year) except for later growing plants plants/seed into small patches Triclopyr and Glyphosate bolt. uninfested areas! are effective at 2-2.5%. - Multiple years are Garlon 3A will not kill Fall rosette treatments needed to exhaust seed grasses. Surfactants can also be added to bank increase efficacy of this IPM method as herbicide treatments. directed in Chemical - Pull at base to avoid section of this breaking stem Escort is also effective. document.

- All pulled plants must be Milestone doesn’t appear bagged and removed. Do to be an effective NOT put pulled plants into herbicide for garlic composting facilities! mustard.

Species Mechanical Chemical IPM Notes/Tips Yellow Flag - Not effective on large Habitat (aquatic approved - Very small - Do not compost Iris infestations imazapyr) and Rodeo infestations can be any parts of plant. (glyphosate labeled for dug; dispose of plants - Repeated mowing or aquatic usage) at the and rhizomes in - If using a herbicide cutting in early summer following ratio: Habitat at landfill or dry and use a surfactant to before seeds mature may 1% and Rodeo at 1.5%, burn. get maximum contain/kill by depleting with seed oil added to the product penetration. energy after many years of mix. - Contain existing intensive mowing. colonies by - Resins in leaves suppression and and rhizome can - Small infestations may be prevention of seed cause skin irritation, pulled or dug out. All spread. wear hand rhizomes must be protection when removed. Incomplete handling. removal may enhance spread of plant. - Applications of aquatic imazapyr - Cutting and covering with products require a landscape fabric or licensed applicator durable tarps moderately with an aquatic successful. endorsement. - Bag and dispose of mature seed heads and bulbs to reduce spread.

Species Mechanical Chemical IPM Notes/Tips - Hand pull small plants. - Cut plants can sprout - Public education. - Note: there are from suckers, so it is . irritating toxins in the - Larger plants can be advisable to apply sap, fruit and leaves pulled with a weed wrench herbicide to stems - Treat small that can cause or similar tool. All of the immediately following infestations by pulling. blindness.. Wear root should be removed to cutting. gloves and other avoid re-growth from root - Cut larger plants protective clothing sprouts. - Triclopyr has been close to ground and when removing or shown to be effective. spray cut stump. cutting. - After pulling, area should Please refer to the PNW be monitored for new Weed Management Spurge seedlings. Handbook for specific Laurel herbicide - More cost effective to use recommendations. mechanical methods for large populations. Plants up to three years old can be controlled by cutting the plant close to the ground. Older plants should be cut below the soil line to minimize re-sprouting.

Species Mechanical Chemical IPM Notes/Tips - Plants can be sprayed -Public education, - Herb Robert is a before flowering (late plant and seed low-growing plant March through April) with available at nurseries that is often growing either a broadleaf and on internet. among desirable - Hand-weed or torch herbicide (if growing with vegetation; isolated plants or small desirable grasses) or with Public education, plant applications of populations before they a non-selective herbicide. and seed available at herbicide should be are in seed. nurseries and on used only where Glyphosate or Imazapyr internet. there are large - Cover with sheet mulch at 1% with Li700 numbers of plants, Shining for at least two growing surfactant. or in soil conditions Geranium that make manual - . control difficult - Heavy mulch (wood debris, chips, etc.) about 3 - Clean boots, Herb Robert inches thick has worked tools, vehicles and well to suppress the pets after visiting plants. parks, forests or other areas where - Mowing or weed eating there are prevents plants from populations of Herb producing seed. It must be Robert. done frequently, as plants will continually produce - Dispose plants that flowers from early spring have been weeded until late fall. in the trash

Species Mechanical Chemical IPM Notes/Tips Knotweeds - Mowing or cutting alone - IMPORTANT: Don’t -To reduce overall - Remember, (Japanese, is not recommended as it spray glyphosate in early herbicide use, cut coverage is typically Bohemian typically encourages the summer. Spray from patches in June, allow more important than giant, knotweed roots to spread onset of flowering through to regrow and spray in product outward. September but before first September. concentration! frost!! Dispose any cuttings - Digging is very labor where they are Applications should intensive, generally causes - Injection tools can be guaranteed not to be directed to both more harm than good, and effective for small resprout! top and underside of should only be reserved infestations and are best canopies and stems for very small patches in used on stems with to ensure complete upland areas. diameter > ¾”. 3ml is the Light deprivation can coverage. Over-the- generally accepted provide some control top treatments miss amount on small isolated many smaller stems, Himalayan) patches. Care must be resulting in regrowth. Imazapyr offers a larger taken to maintain treatment window starting coverage and monitor Injection can result in mid summer. Coverage for out runners. in more water is critical. Take care not to contamination of spray foliage of non-target adjacent streams shrubs and trees. than does foliar - spray - If knotweed is found near water, use herbicides and surfactants approved for riparian use.

Species Mechanical Chemical IPM Notes/Tips Cutting alone is usually The most effective A combination of Young seedlings counter-productive method of Ailanthus complementary control may be pulled or because Ailanthus control seems to be methods may be dug up, preferably responds by producing through the use of helpful for rapid and when soil is moist. large numbers of stump herbicides, which may be effective control of Care must be taken Tree of sprouts and root suckers. applied as a foliar (to the tree-of-heaven. to remove the entire Heaven leaves), basal bark, cut plant including all (Ailanthus stump, or hack and squirt Some examples roots and fragments. altissima) treatment. include bigleaf maple (acer macrophyllum) Triclopyr (Garlon 3A) or Oregon white oak over the counter Bayer (Quercus garryana), Brush Killer (Triclopyr and ponderosa pine amine 8%) (Pinus ponderosa).

Species Mechanical Chemical IPM Notes/Tips - Digging plants is effective - May until flowering is - There are several for small areas best (before seed set) but insects that reduce could be treated any time plant biomass or seed - Disking or roto-tilling can during active growing production control infestations, but season established plants can - An integrated survive if root fragments glyphosate 2-5%+ non- management plan that remain. ionic surfactant ¼ -- ½ % includes selective herbicides and Meadow 2,4-D 2 % + clopyralid ¼ biological control may Knapweed -- ½ %+ non-ionic or show the greatest MSO/silicon blend ¼ -- ½ effectiveness for % removal of meadow knapweed. aminopyralid (7 oz product / ac)+ non-ionic or MSO/silicon blend (1-2 qt/100 gal)

Glyphosate (Round up) English Pull small plants (1” painting cut stems of Resprouting is the diameter) when soil plants larger than 1” biggest challenge, conditions allow. diameter in mid-late so a well-timed summer/dry season. integrated Mowing plants is effective . mechanical plus for suppression only. herbicide program is Plants that have been Cut stump treatment advised repeatedly mowed tend to using Garlon at 30% have a larger root system, Garlon mixed with oil Resprouting from Hawthorn decreasing success with carrier. stem or lateral roots pulling later. is almost a given, Basal bark spray all regardless of the Cutting and then cross- around the base of the method you choose. hatching the stump with an tree using a 1-5% mixture axe or power saw to with water. Seed bank along promote drying out of the fence rows may be a stump. August is a good time to problem. spray the resprouts. Girdling plants is typically Plan for multiple not effective; plants years of treatment resprout from the lateral (e.g., 3 years of spot root system. spraying to control resprouts and new plants).

Important Notes:

PREVENTION

Weed prevention is first element of successful management. Take care not to spread invasive plant seeds and materials as you work or recreate.  Clean boots and tools, and dog companions before and after working at a weedy site.  Increase awareness of vectors by installing informational signs and boot brushes at trailheads to urge hikers to clean clothes, pets, and OHVs.  Dispose of noxious weed material properly. Dry and/or burn pulled or cut plant material. Dry the plant material on a tarp or plastic barrier to prevent soil contact with roots.

WEED CONTROL ESSENTIALS

 Always read and understand the entire label before using any herbicide and surfactant. Wear recommended Personal Protective Equipment and mix herbicides in a safe environment.  ALWAYS follow the recommended rates on the herbicide labels. More is not always better. Determine if lower rate on the recommended range of rates on the label will be effective for your site.  Include spill prevention and preparation of a spill kit and appropriate contact numbers as part of your work habit  Review plant treatment timing to ensure your control efforts are effective for your method and the type of herbicide you choose.  Sustain your work. Reseed and revegetate the area appropriately to help suppress undesirables. Keep an eye on the perimeter of your site. What surrounds your area is likely to move in. Make sure that any planting materials/mulch are weed free.  A surfactant and indicator dye will help with control and efficacy. Note regarding surfactants: Just as with herbicides, read label directions! Some surfactants are appropriate for use with certain herbicides but not others. Also, if using a surfactant on or near water, read label directions to see if the surfactant you are using is approved for aquatic environments.  Glyphosate-based products, such as Roundup and Rodeo are non-selective -- they will kill all green plants!  Herbicides typically work best when applied on temperate (~ 60 - 72 degrees) non-windy days followed by 12 hours of no rain. If temps are cooler and/or there has been limited rainfall, the effects of herbicide application will take longer to become apparent.  Plant material disposal: Completely dry and/or burn pulled or cut plant material. Dry the plant material on a tarp or plastic barrier to prevent soil contact with roots.  With all herbicides, when you apply them is as important as how you apply them. Please consider songbirds and pollinator species when doing weed treatments! Some excellent information can be found at these links:

Protecting nesting song and migratory birds: http://www.portlandoregon.gov/bes/index.cfm?a=322164

Reducing Bee Poisoning from Pesticides: https://catalog.extension.oregonstate.edu/files/project/pdf/pnw591.pdf