Vol. 21, No. 3 Fall 2013 Cal-IPC News Protecting California’s Natural Areas from Wildland Weeds

Newsletter of the California Invasive Plant Council. www.cal-ipc.org

Weeds and wildlife

Pipevine swallowtail butterfly and native bee feeding on bull thistle (Cirsium vulgare) in Walnut Creek Open Space. Photo by Brian Murphy.

IINSIDENSIDE ControllingControlling mayweedmayweed helpshelps ternsterns p.p. 44 SuccessfulSuccessful SpanishSpanish broombroom controlcontrol p.p. 88 StayingStaying “on“on label”label” inin tidaltidal waterswaters p.p. 99 PlantRightPlantRight rollsrolls outout nurserynursery programprogram p.10p.10 TrackingTracking eradicationeradication progressprogress p.p. 1111 GrazingGrazing asas aa managementmanagement tooltool p.12p.12 From the Director’s Desk A ‘cottage industry of criticisms’ By Doug Johnson Cal-IPC s David Richardson and Anthony Ricciardi write in their recent ‘field guide” to 1442-A Walnut Street, #462 Berkeley, CA 94709 Acritiques of invasion science, there seems to be a growing “cottage industry of ph (510) 843-3902 fax (510) 217-3500 www.cal-ipc.org [email protected] criticisms” addressing the field Diversity( and Distributions 19: 1461-1567). Some of the

A California 501(c)3 nonprofit organization critiques are more useful than others. In their generally interesting compilation Invasive Protecting California’s lands and waters and Introduced Plants and Animals: Human Perceptions, Attitudes and Approaches to from ecologically-damaging invasive plants Management (2013) editors Ian Rotherham and Robert Lambert, British environmental through science, education, and policy. historians, conclude that “…intervention in conservation practice hides behind a veneer STAFF Doug Johnson, Executive Director of pseudoscience and certainly challenges democratic processes.” As in many recent Elizabeth Brusati, Science Program Manager critiques, this conclusion is based on an element of truth, but it overreaches the actual Agustín Luna, Business Manager reality in the field. Though they raise critical issues to address, such critiques understi- Bertha McKinley, Program Assistant Dana Morawitz, Mapping Program Manager mate the degree to which these issess are already being examined. This issue of Cal-IPC News touches on one of these topics: the complex interactions DIRECTORS between native and non-native species. Do naturalized non-native plants support native John Knapp, President wildlife? (Sometimes.) Are they an adequate replacement for the native plant species The Nature Conservancy Jason Casanova, Vice-President with whom California wildlife evolved? (Rarely.) In the real world, do managers need to Council for Watershed Health evaluate potential wildlife benefits of invasive plants when determining realistic conser- Shawn Kelly, Treasurer vation goals? (Of course.) Though the underpinnings of the field provides rich intel- Southern California Wetlands Recovery Project Peter Schuyler, Secretary lectual fodder, critics should make sure they are well versed in the ever-dynamic state of Ecological Consultant the discipline so that their criticism is ultimately constructive, not simply contrarian. Peter Beesley Pacific Gas & Electric Company Managing invasive plants, like all conservation, is part science and part societal Jutta Burger values. We pass laws to protect endangered species because we deem it to be the moral Irvine Ranch Conservancy and prudent thing to do. Then science helps us figure out how to do it. Unavoidably, Jennifer Funk Chapman University communication mixes science and values. The term “invasive” has a scientific mean- Gery Gero ing, and also carries significant cultural meaning. As Brendon Larson describes in his Climate Action Reserve Metaphors for Environmental Sustainability: Redefining Our Relationship with Nature Doug Gibson San Elijo Lagoon Conservancy (2011), words take on a life of their own in society’s “metaphoric web” and it is dif- Jason Giessow ficult, but essential, for conservationists to tend their terms over time. Dendra, Inc. Kim Hayes Elkhorn Slough Foundation Annabelle Kleist Capitol Impact On the cover... Dan Knapp Natural resource managers continue to explore the complex interactions between native Los Angeles Conservation Corps wildlife and non-native plants. Non-native plants listed by Cal-IPC as invasive are Virginia Matzek Santa Clara University assessed to have significant negative ecological impact on native California ecosystems Chris McDonald and wildlife. But that does not mean that UC Cooperative Extension Colleen Murphy-Vierra wildlife have no use for these plants. As Brian California Dept. of Food & Agriculture Murphy’s cover photo shows, some native STUDENT LIAISONS pollinators do visit some invasive plants. Don Bridget Hilbig Weden caught the ground squirrel at right UC Riverside Meghan Skaer chowing on yellow starthistle at Rancho San UC Davis Antonio in Santa Clara County (winning 1st Affiliations for identification purposes only. place in our 2013 Photo Contest). Cal-IPC’s recent “Climate-Smart Management” workshop Cal-IPC News asked participants to consider ecological servic- Fall 2013 - Vol. 21, No. 3 es offered by top weeds of concern. Weighing Editors: Elizabeth Brusati and Doug Johnson such information will become increasingly Cal-IPC News is published by the California Invasive Plant important as land stewards design management Council. Articles may be reprinted with permission from the editors. Submissions are welcome. Mention of commercial approaches to meet long-term conservation products does not imply endorsement by Cal-IPC. We reserve the right to edit all work. goals in an age of great environmental change.

2 Cal-IPC News Fall 2013 Cal-IPC Updates mussel to the federal invasive species list, a move strongly supported by the 2013 Symposium goes on despite WildlandWildland governors of western states. miketh- federal shutdown. Adaptive management ompson.house.gov/news/documentsingle. was in full swing as speakers and attendees Weed News aspx?DocumentID=342054 from federal agencies were not allowed Weed News to participate in the 22nd annual Cal- AB763 signed into law. The bill, spon- IPC Symposium, held Oct. 2-5 in Lake management plan focuses on eradication sored by Cal-IPC to strengthen aquatic Arrowhead. See page 6. targets and early detection and rapid invasive plant control in the Delta, passed unanimously through the legislature. Cal-IPC posts new climate adaptation response for new sightings. calweedmap- www.leginfo.ca.gov webpage. Following on the “Climate- per.calflora.org/shf_priorities Smart Land Management” workshop held New Board members. The Cal-IPC Plan to control invasive plants in the at the Symposium, Cal-IPC has posted Board of Directors welcomes Annabelle Delta. The draft Bay Delta Conservation workshop materials and other resources Kleist (Capitol Impact), Virginia Matzek Plan includes a 20-page section on on adapting natural resource management (Santa Clara University) and Colleen Invasive Aquatic Vegetation Control, in to climate change. www.cal-ipc.org/ip/ Murphy-Vierra (California Dept. of Food line with the goals of AB-763. baydelta- climateadaptation & Agriculture). www.cal-ipc.org/about/ conservationplan.com Section 3.4.13. Tahoe Nature Fund will support staff.php. Invasive bamboo on the horizon? regional strategy in the north Sierra. Other Updates Researchers determined that five of The new grant complements existing seven bamboo species tested from East funding for regional prioritization in the Invasive species a top threat to birds. Asian coniferous forests are shade- region stretching from Placer County to Over the last 500 years, invasives are re- tolerant enough to spread in shady Pacific Plumas County. Cal-IPC will work with sponsible for the extinction of at least 65 Northwest forests. link.springer.com/ regional partners like the Truckee River bird species, and are a top factor in recent article/10.1007%2Fs10530-013-0434- Watershed Council. avifauna losses, says a recently released y#page-2 report on the “State of the World’s Birds” Military bases to plan with Cal-IPC. by BirdLife International. www.birdlife. Online library of invasive plant articles. The Dept. of Defense Legacy Program org/datazone/sowb/pressure/PRESS2 With hundreds of articles in a searchable will fund Cal-IPC to develop regional database, TechLine Invasive Plant News is invasive plant management plans with California Congressman establishes bi- designed for “sharing innovative research, resource managers at six installations in partisan group on invasives. Rep. Mike success stories and tips with invasive plant California. www.dodlegacy.org/legacy Thompson from northern California has managers.” techlinenews.com taken the lead in forming a Congressional California CESU admits Cal-IPC. The Invasive Species Caucus. Their first goal California Cooperative Ecosystem Studies is to pass legislationg adding quagga ...continued page 14 Unit (CESU) brings federal and state agencies together with universities and NGOs for research collaboration. New Training DVD from Cal-IPC! ucanr.edu/sites/CCESU Coalition advocates for wildlife “Best Management Practices for programs. Cal-IPC joined1,600 organiza- tions in signing a letter drafted by the Preventing the Spread of Invasive Plants” Teaming with Wildlife coalition urging Congress to continue support for natural This 42-minute training video resources programs such as the North presents important strategies for American Wetlands Conservation Fund preventing the accidental movement and the Forest Legacy Program. In July, of invasive plants, avoiding soil and the House Interior, Environment and vegetation disturbance, planning Related Agencies Subcommittee elimi- ahead for prevention, and promoting nated funding for these programs for the organizational awareness of invasive federal fiscal year that started October 1. plants. Suitable for natural resource teaming.com/news/ managers and those managing transprotation and utility corridors. Shasta-Trinity National Forest uses CalWeedMapper for management Available for $10 plus tax and plan. The Shasta-Trinity is the largest shipping. See trailer and order at national forest in California. Their new www.cal-ipc.org/shop. Cal-IPC News Fall 2013 3 Controlling mayweed chamomile to help endangered terns

California least tern, a federally endangered spe- cies, hovers above invasive mayweed chamomile (Anthemis cotula) looking for a nest site. Photo by Juan Benjuama, wildlife volunteer.

By David L. Riensche, Douglas A. Bell sites, and predation by domestic and stilt (Himantopus mexicanus), killdeer and Cliff Rocha, East Bay Regional Park wild mammals. Loss of suitable habitat is (Charadrius vociferous) and western District; Sara A. Lockett, Northern Arizona known to force species to breed in higher snowy plover (Charadrius alexandrinus University; Cody A. Newell, University of densities or in suboptimal areas that may, nivosus), a federally threatened species. Idaho; Rick Miller, Dow AgroSciences LLC; in turn, increase the risk of predation. The site is managed by the East Bay and Bill Nantt, California Department of Our study site is known as Island Regional Park District (EBRPD), a Transportation Five within a brackish water marsh of two-county special district in Alameda the Hayward Regional Shoreline on San and Contra Costa Counties. Since he California least tern (Sternula Francisco Bay. Island Five is one of 15 2001, EBRPD has aimed to enhance Tantillarum browni) is a migratory islands created within a man-made marsh and manage a successful California least species, nesting from Baja California to system. This island was restored by 4,100 tern colony at the Hayward Regional the San Francisco Bay. Terns establish citizen-scientists who have placed filter Shoreline, while increasing public aware- nesting colonies on sandy soils with little fabric, moved 175 tons of sand/oyster ness and involvement for the protection vegetation along beaches, lagoons, and shells to create nesting substrate, removed of endangered species. bays. Nests are shallow depressions lined vegetation by hand, and monitored terns Invasive plants are a major threat with shells or other debris. Least terns and their potential predators. to many wild bird species. The rapid often have two distinct waves of nesting The Hayward Regional Shoreline colonization of invasive plants can result between mid-April and late September. Marsh system provides habitat for more in substandard nesting habitat. Due to The California least tern was listed as a than twenty nesting waterbird species. its nesting preference for open substrate, federally endangered species in 1970 and The four dominant shorebirds nest- the California least tern is vulnerable as a state endangered species in 1971 due ing at Island Five with the California to the spread of vegetation that can to a population decline resulting from least terns are the American avocet quickly colonize its nesting habitat. loss of habitat, disturbance of nesting (Recurvirostra americana), black-necked From 2009-2011, mayweed chamomile

4 Cal-IPC News Fall 2013 the island, which we believe drew red fox from a line intercept method showed that (in 2009) and raccoon (in 2011) to swim vegetation cover in 2007 was 30% (height to the island and attack duck, shorebird of 24 cm), but vegetation cover reached and tern nests. The combination of 90% (height of 30 cm) in 2011. This limited nest site availability and increased three-fold increase in cover was curtailed predation possibly led to the observed after the application of herbicides, and in reduction in reproductive success for the 2012 vegetation cover was less than 10% terns in 2009 and 2011. (height of 23 cm). A partnership between EBRPD, In the two breeding seasons since the Caltrans, and Dow AgroSciences formed herbicide treatment was applied, the terns in 2012 to address the rapid vegetation have reacted positively to the decrease in growth and cultivate ideal nesting habitat vegetation. During the 2012 breeding for the least tern. Dow AgroSciences con- season, there were 189 incubated nests tributed a combination of Milestone®, at the site, producing a total of 228 Sara Lockett and Cody Newell conduct Capstone®, Rodeo®, and Dimension® chicks. In the 2013 season, the colony California least tern nesting surveys on specialty herbicides to inhibit the growth experienced an amazing 95% hatching a weed-free island during summer 2013. of vegetation at the site. The combination success rate and produced upwards of 118 Photo by David Riensche. of herbicides was used at the recommen- fledglings. The site is now the second dation of local pest control advisors and largest California least tern colony north (Anthemis cotula), a common weed from has been proven to be “practically non- of Ventura County. Thanks to action Europe, became the dominant plant cover toxic” in dozens of laboratory tests and from this partnership to reduce mayweed on Island Five, creating a monoculture field studies. The herbicides were carefully chamomile, the Hayward Regional and confining terns to subpar nesting applied by Caltrans specialists during the Shoreline is now a prime nesting site for sites. The spread of this weed encouraged late winter, prior to the terns’ arrival in this endangered species. waterfowl such as gadwall (Anas strepera), the spring. The treatments resulted in Contact David Riensche at driensche@ mallard (Anas platyrhynchos), and cin- a major decrease in vegetation. Results namon teal (Anas cyanoptera) to nest on ebparks.org.

marsh vegetation. Progress removing Algerian sea lavender In Corte Madera volunteers from by Mike Perlmutter Marin Audubon, Marin County Parks, and San Francisco State have removed lgerian sea lavender (Limonium plants were bolting, but not flowering, plants, but been unable to get 100% Aramosissimum) is an invasive plant therefore easy to see and pull without of the plants each year. Plant size has growing in intertidal areas around risk of seed spread. Each year there have been decreasing, though, and additional San Francisco Bay, as well as along the been fewer plants, and the plants are less resources could knock this population coast from San Luis Obispo to San mature and require less time to remove. out. These pilot efforts show the potential Diego. The Bay Area Early Detection Formerly dense Algerian sea lavender for a comprehensive Bay-wide program to Network (BAEDN) identified it as a patches are filling back in with native succeed if funding can be secured. priority target, and with funding from the San Francisco Bay Joint Venture has led work at sites in Albany and Corte Madera to see the efficacy of removal. BAEDN’s 2013 work party on the Albany shoreline (northern Alameda County) took much less time than in the past, and the progress was clear. The first effort in 2011 took 40 volunteer hours from the Friends of Five Creeks, a local watershed group, to hand-remove this infestation. The patches were dense, with many seedlings establishing underneath mature flowering plants. Followup this year took 18 volunteer hours to remove all the plants, totaling 3 large bags. The timing was perfect, as

Cal-IPC News Fall 2013 5 20132013 SymposiumSymposium inin

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“...another great Symposium! What amazes me is how progressive Cal-IPC is. You are providing land managers with critical information not just about invasive species but relevant ecological restoration topics. I learned more about California ecology and how to make smart future land management decisions at the Cal-IPC conference than I have at any other event in recent years...” ~Cindy Roessler, Midpeninsula Regional Open Space District

Top: Field trippers on the San Bernadino Mountains tour. (Photo by Stacy Gorin. All other photos by Drew Ready.) Above left: Discussion at the poster session, which included six entries in our student contest. Above right: Sponsor booths lined the hallways with information about their organizations. Opposite, clockwise from top left: Sixty entries were submitted to our photo contest, including this shot by Tori Bohlen showing Mills College students pulling French broom seedlings in Tiburon. Naturalist Laura Cunningham gave our keynote address on her book A State of Change: Forgotten Landscapes of California. We tried a different format for this year’s raffle and auction, and the drawing got wild! Ken Moore runs a tool tailgate sharing lessons learned during his years of experience. Cal-IPC board president John Knapp, on right, presents the 2013 Golden Weed Wrench Award to James Law of the Santa Ana Watershed Association.

6 Cal-IPC News Fall 2013 Congratulations to: Jason Giessow (Jake Sigg Award for Dedication and Vision); James Law (Golden Weed Wrench Award, see below), Christy Boser, The Nature Conservancy, and Kate Faulkner, National Park Service for the Califor- nia Islands BioSecurity Program (Policy Award); Josh Volp, Orange County Conservation Corps (Ryan Jones Catalyst Award); Southern Califor- nia Mountains Foundation (Organization of the Year); Student Papers: Chelsea Carey, UC Merced (1st); Justin Valliere, UC Riverside (2nd); Bridget Hilbig, UC Riverside (3rd); Student Posters: Megan Engel, CSU San Bernardino (1st); Daniela Bruckman, UC Irvine (2nd); Madison Hoffacker, Chapman University (3rd).

Presentations and awards posted at www.cal-ipc.org/symposia

Cal-IPC News Fall 2013 7 Successful Spanish broom control in San Diego

By Robert A. James, Caltrans, San Diego

panish broom (Spartium junceum), broom, using an integrated pest manage- Results Snative to the Mediterranean region ment strategy that can include application Over 95% of the plants were eliminat- and Canary Islands (McClintock 1979), is of glyphosate or triclopyr. Basal bark ed one year after initial control. However, a well-known invasive shrub throughout herbicide application has been attempted, noticeably improved results were obtained much of California. It is rated by the but retreatment has been found to be when the switch to triclopyr was made; California Department of Food and needed (Neill 2005). Research on effec- there were fewer resprouting stumps Agriculture as a Class C pest species and tive physical and chemical control was requiring subsequent treatment (<10%). by Cal-IPC as having “high” invasiveness done in Argentina (Sanhueza and Zalba, Germinating broom, with their potential. Spanish broom has been a 2012) with picloram also identified as an photosynthetic stems, nicely contrasted control focus for many years in the state effective herbicide, applied to cut stumps. against dried grasses and other forbs (Bravo 1985). The USDA Forest Service However, picloram does not adhere to soil in late summer, making broom hand has recently undertaken removal projects and has been found in groundwater (EPA removal easier and more thorough. in the San Bernardino and Cleveland 2012). The distribution of emergent broom National Forests with some success in In mid-2012, an infestation of about was patchy and limited. No significant Southern California, particularly using 200 plants was identified for control by erosion was observed. Native species such the herbicide triclopyr (L. Criley, USDA Caltrans along both sides of State Route as buckwheat (Eriogonum fasciculatum) Forest Service, pers. comm.). 67 (post miles 16.5-19) in rural northern and mugwort (Artemisia douglasiana) Leblanc (2001) recommended San Diego County, between the City of have filled in some of the areas previously controlling brooms, including Spanish Poway and the community of Ramona. covered by broom; this ecological recovery Plants were first noted about was also noted by Bravo (1985). 20 years ago, and have in- creased in number and extent Summary and Conclusions (M. Connelly, Caltrans, pers. These results demonstrate that comm.). substantial control is possible with focused, correctly timed initial efforts, Methods and conscientious follow up. Use of An initial cut-stump treat- triclopyr allows for effectiveness without ment was done with glypho- the potential for adverse environmental sate (Roundup®, 50% a.i., effects to water quality that can occur water dilution) in May-July with picloram. 2012. Above-ground biomass I recommend application of triclopyr was left in place where it did to cut stumps in early summer. Leaving not pose a safety concern for the root system in place has the additional motorists, and was allowed environmental benefit of minimizing to discompose. Triclopyr soil erosion, especially on slopes or other (Garlon 4 Ultra®, 15-30% erodible soils. Follow up control must be a.i., water dilution) was used completed the next summer on the lim- for follow-up (and some ited number of stumps that will resprout. new) cut-stump control, At least two follow up visits should be beginning in fall 2012. completed in June and September one Emergent broom plants were year after initial treatment to identify hand pulled when possible, stumps that may resprout at different or cut near ground level and times during the growing season. treated with triclopyr. A Any germinating plants discovered second round of follow-up during follow up visits should be pulled surveys and control efforts by hand, if possible, or chemically treated was done in July-August as described above. Recognizing germinat- 2013, also using triclopyr. ing broom is essential to control success, State Route 67, Post Mile 17.4, north side, before and reduces needed follow up work, as broom removal (March 2012) and after removal well as herbicide use. Recovery of native (September 2013). vegetation will lead to increased shading 8 Cal-IPC News Fall 2013 and ecological resilience, which should also have the benefit of reducing habitat Staying “on label” in tidal waters suitability for broom (Moore 2011). Since related Scotch broom is known by David Thomson, San Francisco Bay Bird Observatory, Habitats Program to have a seed bank that is mainly persis- tent for the first two years (in Leblanc 2001), the treatment area should be he Fall 2012/Winter 2013 issue of characteristics for which tidal data are annually monitored for a total of at least TCal-IPC News contained an article readily available.” See the diagram below two subsequent summers (i.e., for a total entitled “Special concerns near aquatic on tidal waters. of three years after initial control). This habitats” by Drill and Trumbo. The Unfortunately, detailed tidal data are crucial follow up will allow for removal article presents a good review of herbicide usually not available for most sites, and of any germinating Spanish broom when concerns with most aquatic habitats – the alternative methods of using physical individual plants are small and the except for tidal waters. This is a situation markings or lines of vegetation can be recurrence is limited in the area. It is not that applies to all of us managing inter- unclear, even to those of us who have known for certain how persistent the tidal invasive plants like Spartina hybrids spent years mapping coastal wetlands. Spanish broom seed bank is, so a different and Limonium ramosissimum. California’s State Water Resource monitoring period may be warranted In order to stay “on label” with some Control Board (SWRCB) has a new draft based on subsequent observations herbicides you cannot spray “intertidal wetland policy that appropriately defines In speaking with nearby residents areas below the mean high water mark.” the upper tidal boundary: “For all tidal while control efforts were underway, For example, the Telar (XP/XD) labels landscapes, shallow surface water is any several people were unaware of the hazards state: “Do not apply directly to water, or portion of the tidal prism that is bounded of broom, and appreciated the aesthetic to areas where surface water is present, by the local Mean Lower Low Water benefits the plant offered as part of the or to intertidal areas below the mean (MLLW) datum and the local maximum semi-arid landscape. Any control program high-water mark.” But what exactly is the tide height as adjusted for the current should recognize this cultural perspec- mean high-water mark? tidal epoch.” tive and educate stakeholders about the According to the US EPA the However, this still relies on tidal data adverse environmental impacts of the “mean high-water mark” separates that is not generally available for most species; this will help ensure program intertidal coastal and estuarine areas that sites. I encourage the SWRCB and other support and potentially allow the efforts are exposed during low tide but covered regulatory agencies to work on providing to be extended to private lands. during high tide from adjacent terrestrial more specific guidance on how the label By following these straightforward areas. EPA says the definition varies by term “mean high-water mark” should be approaches, scaled to available resources state, but in general it’s “the line on the determined by herbicide applicators. and the areas of concern, the challenge of shore established by the average of all high Especially with the added complexity controlling Spanish broom can be won. tides. It is established by survey based on of climate-induced sea level rise, those of us working to protect intertidal habitats Special thanks to Caltrans Maintenance available tidal data (preferably averaged need even more straightforward and staff, especially Kathlene Manini, Donald over a period of 18.6 years because of the effective methods for assessing where Parker, and Daniel Schmidt. Contact the variations in tide). In the absence of such herbicides can and cannot be used on our author at [email protected] data, less precise methods to determine the mean high-water mark are used, such work sites. References as physical markings, lines of vegetation Contact the author at d.x.thomson@gmail. Bravo, L.M. 1985. We are losing the war against or comparison of the area in question broom. Fremontia 12(4):27-29. com. with an area having similar physical EPA. 2012. Basic information about picloram in Diagram: US Army Corps of Engineers drinking water. Retrieved from water.epa.gov/drink/ contaminants/basicinformation/picloram.cfm Leblanc, J.W. 2001. Getting a handle on broom: Scotch, French, Spanish, and Portuguese brooms in California. Univ. of Calif. Agriculture and Natural Resources, Publication 8049. McClintock, E. 1979. The weedy brooms: where did they come from? Fremontia 6(4):15-17. Moore, K. 2011. Long-term broom management. Cal-IPC News 19(3):6-7. Neill, B. 2005. The basal bark method of applying triclopyr herbicide. Cal-IPC News 13(1):8-9. Sanhueza, C. and S.M. Zalba. 2012. Experimental control of Spanish broom (Spartium junceum) invading natural grasslands. Management of Biological Invasions 3(2):97-104.

Cal-IPC News Fall 2013 9 Retail nurseries get recognition and training from PlantRight By Jan Merryweather, Sustainable Conservation

ith the launch of its free Retail environmental and horticultural industry garden center. Send an email with your WNursery Partnership program, groups. The nonprofit group Sustainable local garden center’s name and contact PlantRight becomes the go-to resource for Conservation in San Francisco oversees information to [email protected]. California nursery retailers interested in the partnership. Cal-IPC has been a building expertise on ornamental invasive member of the coalition since its incep- plant issues and opportunities. It’s one tion in 2004. more way for retailers to demonstrate,’We PlantRight’s training materials and Care!’ when it comes to selling regionally science-based educational content are appropriate and environmentally-friendly easy-to-access, practical, and avail- plants. able 24/7, so that even the busiest Nurseries joining the program agree garden center professional can benefit. to not sell plants listed by PlantRight as Nurseries can learn more about this free invasive, and to educate their customers program by visiting: www.plantright.org/ and staff about the problems caused by create-your-plantright-account. invasive plants. If you like the sound of this program, PlantRight is a project of the and would like to see more PlantRight California Horticultural Invasives nursery partners in your area, take a Partnership (Cal-HIP), a coalition of moment to introduce us to your local

“PlantRight training allows us to make responsible purchasing choices, share our philosophy with custom- ers, and offer reasonable alternatives to popular invasive species. I would encourage all garden center owners and managers to participate in this partnership.” Charlie Keutmann, Owner, The Garden Company (Santa Cruz)

“When PlantRight approached Sloat Garden Center, joining forces was a slam dunk. PlantRight’s ef- forts helped solidify and train our team with a singular, cohesive message that can easily be commu- Cal-IPC recently reprinted two of nicated to our customers through our “Don’t Plant a Pest!” brochures signage, handouts, on-line presence featuring invasive ornamental plants and team member knowledge. to avoid as well as suitable landscaping Retailers across the country should alternatives. The San Francisco Bay embrace these types of efforts to Area brochure and the statewide Trees educate our customers, helping brochure are available once again. them make more informed and They are great educational resources responsible decisions.” for plant sales or garden tours. We Dave Stoner, President/CEO, Sloat can provide up to 10 copies for free; request them by emailing info@ The Garden Company in Santa Cruz Garden Center, Inc. (Nine locations cal-ipc.org. Larger quantities may be proudly displays its PlantRight window in the San Francisco Bay Area) ordered from www.cal-ipc.org/shop. decal.

10 Cal-IPC News Fall 2013 to tell us the seed longevity of each. He Tracking eradication progress was not able to find good information. We have also found information in books By Vince Guise, Contra Costa County Agricultural Commissioner written by well-respected authors to be different than what we find in the field. ocumenting weed work in a manner individual populations, though we gener- The sidebar lists the seed bank longevity Dthat shows progress toward our goals ally can show an overall decline in net that we have observed for the plants we is a challenge that all weed workers face, acres on the property. are working on. especially when we are aiming for eradica- One idea that is sometimes used is Another factor is missed plants. This tion. Here are some of our practices and “eradicating to seed bank,” meaning that extends eradication time due to new seed experiences from Contra Costa County. all plants are treated or removed to where introduced into the soil. And I strongly We have 17 noxious/invasive weed no new seed is produced. This would disagree with any “one acre or less” species that we deal with as a department. help to show short-term progress though eradication thought. If you don’t get it all, In our program we are trying to eradicate real eradication can be many years down the plant can and likely will come back. 15 of the 17 species. It takes persistent the road. If eradication to seed bank is Most of these species seem to have a and dedicated field work to get rid of accomplished from year to year (as in our “breaking point” when net acres fall off some of these species. Due to limited significantly. With artichoke thistle, for resources and other considerations we are Observed seed bank longevity: example, it is 3-5 years. Populations of trying to manage the other two species, some species bounce around for a few Artichoke thistle: 15-20 years perennial pepperweed and pampas grass, years before reaching a breaking point. by treating satellite infestations found in Purple starthistle: 8-12 years Purple starthistle goes up and down for new areas and some leading edge areas. Red sesbania: 8 program years so far 6-7 years before dropping off to a low We document the work that we and we expect 30+ year seed life level. However we have noticed in the perform on a property-by-property Barb goatgrass: 3-4 years last two years since we started using basis and have been doing so for the 34 Perennial pepperweed: 3-4 years (less MilestoneTM on artichoke thistle and years of our program. Some properties if the area is treated with TelarTM ) purple starthistle that these species crash are small, 5- or 10-acre ranchettes, and Russian knapweed: 3-5 years to lower levels much faster than with others are ranches or regional park open materials we used before. It seems that White horsenettle: <5 years, though space areas that are well over 1,000 acres. new germinating seed of these species may stolons seem to be difficult We document each weed species treated, be sensitive to low residual levels in the the date of treatment, the treatment Carderia, whitetop (lens and heart- soil since this effect seems to carry over type, the name and amount of concen- podded): 3-6 years from year to year. trated product if herbicides are used, the Purple loosestrife: 11 program years Eradication depends on the tools person(s) that performed the application and counting available, the dedication and persistence on the property, the gross acres surveyed Oblong spurge: >12 years of individuals, and the structure of the and the net acres treated. We don’t track Smooth & woolly distaff thistle: 6-10 program. One of our success stories s is separately the individual infestations years a 1,060-acre ranch that was first treated of a species on the same property. We Kangaroothorn: >8 years near the beginning of our noxious weed do track separately the different species program. In 1983, 22 net acres of arti- Pampasgrass: 1-2 years treated on each property. We treat all of choke thistle were treated by air. Besides the targeted species each year with a goal Japanese knotweed: Does not produce dense patches, there were also scattered of not allowing new seed to set. seed in our area, but deep rooted stolons individual plants throughout this prop- Our main indicator of progress take 2-3 years with Imazapyr erty. Over the years the net acreage on this on a property is net acres treated over Japanese dodder: Also does not ranch has diminished to the point that the years. Eventually we will come to produce seed in our area but small rem- we now count individual plants. We had eradication of the species on the property, nants that are missed when host plants 42 plants this year and expect there will after three years of no detected plants are removed can keep the infestation be zero plants in the next 2-3 years. We of the targeted species on the entire going until they are detected. Usually have had many properties that followed property. One of the problems with this 2-3 years maximum. the same pattern with some reaching total is that it does not take into consideration eradication. This goal should be the gold the multiples of small infestations that program) then it is a matter of persistence standard for our work, but it requires may have been eradicated from the until the seed bank is finally depleted and steady funding and attention, which we property previous to the overall eradica- true eradication is achieved. have been fortunate to have in our county. tion. This all-or-nothing property-by- It is very difficult to get good informa- Contact the author at Vince.Guise@ property approach does not fully show the tion on seed bank life in field situations. ag.cccounty.us. progress that we have made in eradicating We have asked the CDFA Seed Botanist Cal-IPC News Fall 2013 11 Prescribed grazing for invasive plant control on rangelands

By Josh Davy, UC Farm Advisor, Tehama, Glenn, Colusa Counties, Kenneth Tate, UC Range Specialist, and Leslie Roche, Post-doc- toral Researcher at the UC Davis Rangeland Watershed Lab ost herbicide weed control meth- Mods are good at initial control, but can lack long-term weed management effectiveness if weeds are allowed to re- establish. Grazing is a tool that can offer an opportunity to suppress herbaceous weed populations on rangelands over a longer term. However, grazing should be thought of as a weed “management” tool because grazing does not usually control every plant treated. Instead, grazing can be used to restrain the prolific seed production of annual weeds or root carbohydrate storage of perennial weeds. Depending on the situation, grazing and herbicide weed control methods can be used independently or in cooperation. Fenced cattle in medusahead timed grazing research trial. Photo by Josh S. Davy There are important factors to keep in mind when approaching a grazing management option for weed control. management on rangeland. These include: reproduction and have a reduced chance Unlike herbicides that can make an im- 1. Exhaust the root reserves of annual of surviving dormancy. If adequate mediate impact on large weed populations plants through defoliation as soil moisture is available, the plants are able to regardless of soil and weather conditions, moisture is being depleted. This in- recover from grazing. grazing is more complicated and depen- hibits the plants’ ability to make seed Clay soils with high water storage po- dent upon site-specific conditions. for subsequent-year germination. tential, or late growing-season rains after Also, herbicide control entails less grazing ends, can hinder the effectiveness 2. Repeated grazing of perennial weeds physical infrastructure such as fencing and of grazing. Deep-rooted plants are better just prior to the onset of dormancy. does not require a skilled cowboy to keep able to tap soil moisture than shallow Defoliation of plants at this time livestock fenced on the targeted area. rooted plants, usually making a single exhausts root reserves required by Finally, livestock are bred primarily to target grazing more successful on shal- plants during the dormant period and produce food and fiber. Although using lower rooted annual plants than biennial entering the next growing season. livestock for weed control is a double bo- or perennial weeds. This can be positive nus, it means that maintenance of animal 3. Remove thatch and open up the if a manager’s goal is to lessen the impact nutrition demands while “meating” weed canopy to allow desirable plants to of invasive annual grasses on deep-rooted management goals is very important. establish. This is mostly helpful with native perennial grasses. Factors such as running out of livestock weeds that create a monoculture such Examples of successfully managing drinking water or a late season reduction as medusahead. Published scientific weed populations exist. The follow- in forage quality before optimal defolia- support for this strategy is limited. ing three examples depict what we have learned from targeted grazing on annual, tion levels are hit can impact weed control The first two strategies are the essential biannual, and perennial plants. Many success from year to year. It may also components for reducing weed density in more published examples exist. require thought about the class of animal a target area. The key to implementing used for targeted grazing specific weeds. the first two strategies is timing, timing, • Heavy defoliation of medusahead (Ta e- For example, mature dry cows may serve and timing of defoliation. Target weeds niatherum caput-medusae) in late spring better for consuming low quality forages need to be heavily defoliated as soil mois- as plants are entering the bolt stage has than growing yearling cattle or lactating ture is depleted at the end of the growing proven very successful in limiting seed cows. season. Without moisture to recover, production and subsequent year’s plant Three main strategies exist for weed defoliated plants senesce with little or no density (DiTomaso et al. 2008). 12 Cal-IPC News Fall 2013 • Yellow starthistle (Centaurea solstitialis) led by the California Rangeland Water- It is important to note that the “target required multiple heavy grazing ses- shed Laboratory is examining the long- style” grazing strategies for weed control sions late in the season to reduce seed term effects of four grazing treatments. described above are not the only way that production due to the plant’s deep roots The lab has completed the first year of grazing can affect weed management. Any (Thompsen et al. 1993). implementing treatments of seven-month defoliation of weed plants has an impact • McKell et al. (1966) found repeated continuous grazing, four-month fall and on their subsequent seed production defoliation of hardinggrass (Phalaris spring grazing, four-month fall and spring or the amount of thatch accumulated. aquatica) during spring prior to dormancy targeted grazing, and winter-only grazing. Grazing can also have a positive effect on could cause plant death. Fundamentally The lab has implemented the project at the reduction of fire fuel loads. A graz- showing deep-rooted perennial plant con- a ranch scale (over 1200 acres, using over ing strategy with a moderate continuous trol is possible using repeated defoliation 360 cattle) and is monitoring multiple pa- stocking rate does reduce weeds such as as a strategy. rameters including yearling cattle produc- medusahead and starthistle when com- Exciting new research at the Sierra tion, invasive and native plant responses, pared to non-grazed areas. With this graz- Foothill Research and Extension Center and other ecosystem responses. ing scheme it may be that effects are not seen on high rainfall years or years with significant late growing season rainfall, but effects may be seen during drought years or years with an early end to rainfall. As stated earlier, grazing treatments rarely control the entire weed population. Rainfall’s influence on a grazing treat- ment’s “perfect” timing can cause success to vary from moderate to high between years. Because of this, grazing should be implemented only as a long-term weed management strategy. Such moderate single-season success in weed management can compound over years into drastically lower weed populations. References DiTomaso, J. M., G. B. Kyser, M. R. George, M. P. Doran, and E. A. Laca. 2008. Control of medusahead (Taeniatherum caput-medusae) using timely sheep graz- ing. Invasive Plant Science and Management. 1:241–247 McKell C. M., R. D. Whalley, V. Brown. 1966. Yield, Survival, and Carbohydrate Reserve of Hardinggrass in Relation to Herbage Removal. Journal of Range Man- agement. 19(2): 86-89 Thomsen C., W. Williams. M. Vayssiéres, F. Bell, and M. George. 1993. Controlled grazing on annual grass- Medusahead at the proper phenological stage to begin a targeted grazing treatment. land decreases yellow starthistle. California Agriculture. 47(6):36-40. DOI: 10.3733/ca.v047n06p36 Photo by Josh S. Davy

Impacts of native vs. exotic invasive grasses have become prevalent, native species (common mix of species such as medusahead and barbed goatgrass. used for restoration in California’s Central grassland vegetation Control of these newer invasive grasses, or Valley). After 3 years,we assessed the im- restoration of natives is not possible in all pacts of these vegetation types on multiple By Valerie Eviner, Joanne Heraty, Jill Baty, impacted areas, due to the broad extent ecosystem services. When comparing Carolyn Malmstrom, and Kevin Rice, UC of these invasions. Ecosystem services are natives to naturalized species, natives Davis Dept. of Plant Sciences a potential criteria to prioritize areas for increased soil nitrogen availability, and [Abstract from poster presented at the 2013 restoration and weed control. were much better at suppressing invasive Cal-IPC Symposium] We planted plots consisting of three weeds. However, the naturalized species California’s grasslands have been domi- community types: naturalized exotic plots provided better erosion control, nated by annual exotic grasses for the species (that have dominated California’s mitigation of soil compaction, water qual- grasslands for 200-300 years), invasive past 200-300 years. More recently, newer ...continued page 14 weeds (goatgrass and medusahead), and Cal-IPC News Fall 2013 13 ...continued from page 13 ity, and soil water storage. This suggests that Thank you 2013 Symposium Sponsors! restoration of natives will be most beneficial in areas with high invasive weed pressure, but PLATINUM Dow AgroSciences could be detrimental in areas where erosion, ACS Habitat Management Sacramento Municipal Utility compaction, and water quality are of concern. District Invasion of noxious rangeland weeds into California Association of Local Con- the naturalized community did not enhance servation Corps State Coastal Conservancy any ecosystem services, and greatly decreased Pacific Gas & Electric Company GREEN palatable spring forage quantity. However, there is a tradeoff between invasive weeds GOLD American Conservation Experience and native species. Invasion of noxious weeds The Nature Conservancy California Association of Resource Conservation Districts into native communities decreased spring USDA Forest Service forage availability and decreased soil nitrogen California Native Grasslands availability, but enhanced soil water storage, SILVER Association compaction alleviation and water quality. This Center for Natural Lands Management Dendra, Inc. suggests that sites that are less vulnerable to soil degradation would be best to prioritize for Chapman University, Schmid College Dudek and Habitat Restoration of Science & Technology invasive weed control. Sciences, Inc. While the impacts of invasive grasses on Hedgerow Farms Garcia and Associates California’s flora are an important criterion National Park Service, California Irvine Ranch Conservancy for restoration and weed control, it is not Exotic Plant Management Team possible to manage all invaded areas. Thus, RECON Environmental/ Santa Ana Watershed Association RECON Native Plants, Inc. prioritization of sites for management should consider that some of these invasive grasses are BRONZE Resource Conservation Partners improving soil conditions and water quality. California Native Plant Society SERCAL Contact the author at [email protected].

Wildland Weed News, cont’d... Weed Control in Natural Areas Undergraduates help National Wildlife refuges. Eight universities including UC Santa Barbara participated in a in the Western United States combined seminar which compiled data on invasive plants Published in 2013 in nearby refuges, including habitat richness and evenness, by the University elevational range, native species diversity, refuge size, and of California’s the regional pool of invasive species. Results were combined Weed Research and for a continental-scale analysis. They found that patterns are Information Center, highly variable among regions, suggesting that management with 15 contributing strategies for invasive species are best formulated at the authors. regional level. Santa Barbara Independent, August 22. The manual presents Does it matter whether a plant is native? Dr. Mark Davis detailed information of Macalester College and Dr. Daniel Simberloff of the on biology and University of Tennessee-Knoxville debated when, if, and control methods for how conservation biologists and managers should deal with 340 species found non-native species. A recording of “Native and non-native in thirteen western species: How much attention should managers be paying states. Includes tables to origins?” is available at distancelearning.fws.gov/players/ summarizing chemical con_sci.html. and non-chemical Eucalyptus: friend or foe? The online science blog control options. $37.00 plus tax and shipping from for KQED public radio in San Francisco describes the 544 pages with photos. the Cal-IPC online store. controversies surrounding removal of eucalyptus stands in the East Bay. blogs.kqed.org/science/2013/06/12/ Order at www.cal-ipc.org/shop eucalyptus-california-icon-fire-hazard-and-invasive-species/

14 Cal-IPC News Fall 2013 Thank You for Supporting our Work!

New and Renewing Organizational Members California Weed Science Society Individual Members: Center for Natural Lands Stewardship Circle ($1,000) Management Peter Beesley, Grass Valley City of Walnut Creek Jason Casanova, La Crescenta County of Lake Agricultural Peter Schuyler, Santa Barbara Commissioner’s Office Steve Schoenig, Davis Jake Sigg, San Francisco DriWater, Inc. Dudek and Habitat Restoration Champion ($500) Sciences, Inc. (HRS) Edith Allen, Riverside Forester’s Co-Op Paul Aigner, Lower Lake Habitat West, Inc. Gary Gero, Los Angeles Hedgerow Farms Doug Gibson, Encinitas John Knapp, Santa Barbara Inyo County Water Department Mendocino Redwood Company Partner ($250) National Park Service - California Jutta Burger, Tustin Exotic Plant Management Team Frank Davis, Santa Barbara Lynn & Rick Frame-Hoskins, Pacific Gas and Electric Company Mill Valley RECON Environmental /RECON Jason Giessow, Encinitas Native Plants, Inc. Shawn Kelly, Oxnard Rocky Mountain Elk Foundation Dan Knapp, Los Angeles Santa Ana Watershed Association Jean Schuyler, Santa Barbara SERCAL Kathy Welch, Truckee ACS Habitat Management Paul Ziemann, Riverside California Association of Local Shelterbelt Builders, Inc. Daniel Kellog, Gold Hill, OR Conservation Corps Sierra Foothill Conservancy Lincoln Smith, Albany California Native Grasslands Southern California Mountains Ann Howald, Sonoma Association Foundation Mary Millman, Berkeley California Native Plant Society Sweetwater Authority Helen Conway, San Jose The Huntington Library High-school student Connor describes The Nature Conservancy weed projects at the National Children’s US Fish and Wildlife Service - Forest during the San Bernardino Inventory and Monitoring Program Mountains field trip at the Symposium. USDA Forest Service

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Northern California Botanists Northern Rockies Invasive Plant Invasive Weeds Awareness Day at the January 13-15 Council Capitol Chico February 10-14 March 12 www.norcalbotanists.org Spokane, WA Sacramento www.regonline.com/2014nripc www.cal-ipc.org California Weed Science Society January 22-24 Western Society of Weed Science SERCAL Monterey March 10-13 May 13-15 cwss.org Colorado Springs, CO Santa Rosa www.wsweedscience.org www.sercal.org

“If we really want to change people’s minds about invasive plants, I think we need to re-name them... Himalayan blackberry could probably be called “ravening monsterthorn” without anybody who is familiar with it complaining.”

- Ursula Vernon, “A Matter of Names”, nativeplantwildlifegarden.com/a-matter-of-names/