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Secondary Weeds

Secondary Weeds

  • Encyclopedic in scope, this book is the first to cover North American weeds at every stage of growth. The book is organized by plant family, and more than five hundred species are featured. Each receives a two-page spread with images and text identification keys. Species are arranged within family alphabetically by scientific name, and entries include vital information on seed viability and germination requirements.

  • This field guide focuses on the most problematic weeds in northwestern North 
    America for which there are at least some biocontrol agents established. Multiple 
    photos and descriptions of each weed included in this guide emphasize key 
    identification traits and plant ecology. Comparison tables are included to further 
    aid in identification of related weed species, where applicable. For each weed 
    included in this guide, all biocontrol agents currently found in North America are 
    described individually.
  • This website enables users to use search functions to identify unknown weed species. 

  • This document provides photos and characterists of the Colorado Watch List species. 

  • This easy-to-use website site-specifically estimates spotted knapweed and leafy spurge impacts on grassland biomass production and wildlife and livestock forage.  The weed impact calculations help land managers identify appropriate weed management option for their situation.

  • The 2016 Compendium of Herbicide Adjuvants is the 13th edition of the biennial publication and contains 779 entries from 38 companies. While the Compendium of Herbicide Adjuvants is published every two years, the associated website is updated more frequently. This Compendium organizes adjuvant products by type (such as nonionic surfactants, crop oil concentrates, etc.). And each listing includes the product name, manufacturer/distributor, principal functioning agents, use rates, and comments. 

  • CDMS Website

    For a quarter of a century, CDMS has delivered the most comprehensive market access to critical agro-chemical information and decision support tools for the agricultural, turf & ornamental, and food industries.

  • The proposed action includes the removal (hand cutting and herbicide treatment) of existing and potential arundo (Arundo donax) plants at 11sites (915 acres) located along the Virgin River in Washington County, Utah. The proposal also includes the removal (hand cutting and herbicide treatment) of existing Russian olive (Elaeagnus angustifolia) and tamarisk (Tamarisk Species) trees at three sites (170 acres) near Rockville, Utah and Washington, Utah. Removal of these exotic invasive species would improve habitat conditions for woundfin (Plagopterus argentissimus, Federally Endangered), Virgin River chub (Gila seminuda, Federally Endangered), Southwestern Willow Flycatcher (Empidonax traillii extimus, Federally Endangered), Yellow-billed cuckoo (Coccyzus americanus occidintalis, Federal Candidate Species), several BLM Sensitive species and other wildlife species along the river.
  • This guide by Drs. Scott Nissen, Andrew Norton, Anna Sher, and Dan Bean offers targeted guidance on how to develop management plans, implement various control strategies, and plan restoration for treated sites. 

  • This document describes steps that can be taken to control Arundo donax (also known as giant reed, giant cane, and arundo) in the Virgin River Watershed and Washington County, Utah.
  • This resource provides guidelines on treating woody invaives and secondary weeds with the recommended timing and type of herbicide.
    Developed by Fremont County Weed Management for Fremont, Custer, & Surrounding Counties
    April 2015
    Please see Fremont County Weed Control’s booklet, “Guideline for Weed Management Plans” for more details such as herbicide rates and specifics about weed control methods.
  • This website, by Agrian, allows users to look up herbicide label information from their extensive database. Over 9,000 indemnified manufacturer/registrant labels and supporting documents (including MSDS, Section 24c, 2ee, and organic certificates) are provided. 

  • While focused on Victoria, Australia, this guide provides any restoration practitioner with helpful information on highly efficient and cost effective revegetation methods. This publication aims to provide the practical 'know how' to help carry out your revegetation from start to finish. Section A covers the steps involved in a revegetation program, from planning and preparation to monitoring.
  • This brochure, developed by Fremont County Weed Management, for Fremont, Custer, and surrounding counties, provides mechanical, chemical, biological and cultural control information for a variety of common weed species. 

  • This report details American Conservation Experience's efforts to treat Arundo donax along 39 miles of the Virgin River. 

  • This guide provides photos of often misidentified annual weeds found in Weld County, Colorado. 

  • Abstract:
    Along the U.S.-Mexico border, an aggressive non-native grass, giant cane (Arundo donax), grows in dense, nearly impenetrable stands along hundreds of kilometers of the Rio Grande/Bravo (RGB). Between 2008 and 2018, a diverse, multisector binational-team repeatedly treated giant cane with prescribed fire and herbicide along 90 km of this binational river to restore aquatic and riparian habitat and native plant community composition. The large geographic scale, binational management response, treatment methods used, and development of a long-term monitoring pro- gram to quantify treatment impacts on the RGB's riparian plant community under-score the unique aspects of this effort. Results of this decade-long management experiment indicate that (i) the combination of a primary treatment of giant cane (using prescribed fire followed 4–6 weeks later by herbicide treatment of regrowth) and a secondary treatment (spot treatment of regrowth one or more years following primary treatment) was effective in reducing the extent and distribution of giant cane at relatively low cost, (ii) giant cane re-establishment following treatment is often not rapid, nor dramatic; and (iii) as revealed by analysis of riparian vegetation monitoring data, eradication of dense stands of giant cane have fostered significant and long-term reduction in giant cane cover and recovery of native woody riparian plant taxa.
    Important caveats to the long-term viability of managing giant cane hinge on better understanding the consequences of herbicide use, securing funding to cover the cost of re-treatment, and continuing river flow management focused on promoting the recovery of native riparian obligate plants over non-natives.
  • Executive Summary
    Utah is experiencing a dramatic invasion of an aggressive European subspecies of the common
    reed (Phragmites australis subsp. australis). This invasion is threatening recreation resources,
    wildlife habitat, and native wetland ecosystems. In this study, we used genetic tools to determine
    how, and to what extent, introduced Phragmites is spreading among major Utah wetlands. We
    also assessed native Phragmites (Phragmites australis subsp. americanus) spread to put our
    introduced Phragmites results in context. In addition, we determined if native Phragmites is
    being replaced by introduced Phragmites and if the two subspecies are hybridizing. Our results
    indicate that introduced Phragmites is effectively reproducing and dispersing through both
    rhizomes and seed but compared with native Phragmites, seems to be spreading largely by seed.
    Also, we found that levels of gene flow among Utah wetlands is quite high for introduced
    Phragmites, especially compared with the limited gene flow we found among native Phragmites
    populations. We found no evidence that native and introduced Phragmites are hybridizing, even
    where they coexist. In most locations, native Phragmites is not being replaced by introduced
    Phragmites. However, at Utah Lake, both subspecies co-occur and native Phragmites may be
    replaced by introduced Phragmites if it is not already. Based on our findings we recommend: (1)
    that control and prevention efforts for introduced Phragmites should target both forms of
    dispersal but focus on seeds and (2) that managers carefully monitor locations like Utah Lake,
    where the two subspecies are co-occurring, to prevent loss of native to introduced Phragmites.
    Common Reed (Phragmites australis): Nativity and Determining Lineages Using Genetics and Field Characters in Southeastern Utah (and Parts of Southwestern Colorado)
    Kelli Quinn1*, Liz Ballenger2
    1Southeast Utah Group National Park Service, Moab, Utah, USA;
    2Southeast Utah Group National Park Service, Moab, Utah, USA;
    There are three lineages of common reed (Phragmites australis) recognized in North America: native lineage, American common reed (P. australis subsp. americanus); Gulf Coast lineage, subtropical common reed (P. australis subsp. berlandieri); and introduced lineage, European common reed (P. australis subsp. australis). The exotic European lineage is of concern due to its invasiveness and observations of its spread to our area of the Colorado Plateau.
    There are morphological traits differentiating these lineages, but field identification can be challenging. Genetic testing is the best way to confirm the correct lineage of common reed. In the late summer/ fall of 2019, we identified common reed stands based on diagnostic field characters. In spring of 2020, we will be collecting common reed tissue samples to send to a lab for genetic testing and confirm our field identification. The primary goals of this project are 1) to better refine and build confidence in the identification of common reed lineages using morphological traits in the field, and 2) gather information on the distribution of nonnative common reed populations in southeastern Utah.
  • Gonzalez et al. 2017

    Abstract: Control of invasive species within ecosystems may induce secondary invasions of non-target invaders replacing the first alien. We used four plant species listed as noxious by local authorities in riparian systems to discern whether 1) the severity of these secondary invasions was related to the control method applied to the first alien; and 2) which species that were secondary invaders persisted over time. In a collaborative study by 16 research institutions, we monitored plant species composition following control of non-native Tamarix trees alongsouthwestern U.S. rivers using defoliation by an introduced biocontrol  beetle, and three physical removal methods: mechanical using saws, heavy machinery, and burning in 244 treated and 79 untreated sites across six U.S. states. Physical removal favored secondary invasions immediately after Tamarix removal (0–3 yrs.), while in the biocontrol treatment, secondary invasions manifested later (> 5 yrs.). Within this general trend, the response of weeds to control was idiosyncratic; dependent on treatment type and invader. Two annual tumbleweeds that only reproduce by seed (Bassia scoparia and Salsola tragus) peaked immediately after physical Tamarix removal and persisted over time, even after herbicide application. Acroptilon repens, a perennial forb that vigorously reproduces by rhizomes, and Bromus tectorum, a very frequent annual grass before removal that only reproduces by seed, were most successful at biocontrol sites, and progressively spread as the canopy layer opened. These results demonstrate that strategies to control Tamarix affect secondary invasions differently among species and that time since disturbance is an important, generally overlooked, factor affecting response.

  • This document describes the biology and management implications of reed canary grass, a rhizomatous perennial grass that is currently found in all but six of the lower 48 states.  

    The Western Governors’ Association (WGA) and the U.S. Department of Agriculture (USDA), under a Shared Stewardship Memorandum of Understanding (MOU), agreed in June 2019 to pursue an effort to meaningfully address the large-scale infestation of invasive annual grasses on western forests and rangelands. The spread of invasive annual grasses – such as cheatgrass, medusahead and ventenata – is causing major damage to western working lands. To date, many control efforts have been reactive, focusing on highly infested areas where control is more expensive and has a lower likelihood of success.
    One product of this effort is a new toolkit for land managers working to combat the spread of invasive annual grasses in the West. The toolkit is comprised of three elements:
    • A roadmap for invasive grass management in the West, with new best management practices for the identification, protection, and expansion of “core” areas – regions with relatively low, or no, annual grass invasion;
    • Case studies highlighting the application of these practices in Idaho and Wyoming; and
    • A new geospatial data layer (which uses analytical tools to compile existing federal data) to help state and local managers assess invasive annual grasses within their jurisdictions, while also offering opportunities to identify new cross-boundary collaborative projects.
    The roadmap and data layer are designed for easy integration into local management plans and can be tailored by state and local managers to reflect local data, knowledge, capacities and priorities.
  • Click the link above to access the Russian knapweed fact sheet produced by Colorado State University Extension.

    Choked Out: Battling Invasive Giant Cane (Arundo Donax) Along the Rio Grande/Bravo Borderlands
    Mark Briggs1*, Helen M. Poulos2, Jeff Renfrow3, Javier Ochoa-Espinoza4, David Larson5, Patty Manning6, and Joe Sirotnak7, Kelon Crawford8
    1RiversEdge West, Tucson, AZ;;; (520) 548-4045
    2Wesleyan University
    3Rio Grande Scientific Support Services
    4Comisión Nacional de Áreas Naturales Protegidas
    5Big Bend National Park
    6Sul Ross State University (retired)
    7Bureau of Land Management
    8Rio Grande Scientific Support Services
    Biological invasions have myriad negative impacts on native biota and human livelihoods, worldwide. Along the U.S.-Mexico border, giant cane (Arundo donax), an aggressive non-native grass, grows in dense, nearly impenetrable stands along hundreds of kilometers of the Rio Grande/Bravo (RGB). Between 2008 and 2018, a diverse, multisector binational-team treated giant cane along 90 Km of this binational stretch of the river to improve aquatic and riparian conditions for native species as well as to enhance river access for riverside citizens and visitors. Monitoring of riparian plant cover over a ten-year period reveal significant reduction in giant cane cover and recovery of native woody riparian plant taxa.  However, continued management and monitoring is needed to better understand the long-term efficacy of this effort. As part of our presentation, we will highlight:
    • The methods used to manage giant cane;
    • The debate – Central points that our binational team discussed as part of making the decision to move forward with a concerted effort to manage giant cane;
    • Results: In addition to highlighting results of long-term riparian vegetation monitoring, we will also discuss other general takeaways from this work, including impacts of giant cane management on channel morphology, site conditions that appear to have a strong bearing on the effectiveness of management actions, working binationally, and the introduction of biologic agents to manage giant cane.
    • Taking stock as we look to the future.

RiversEdge West's

mission is to advance the restoration of riparian lands through collaboration, education, and technical assistance.