Agenda 12/11/19

Glen St Mary Learn & Burn Workshop

8:30-9 AM Registration

9:00 AM-9:15 AM – Welcome & Introduction

9:15 – 9:35 AM – Problems with Invasives

9:35 – 10:25 AM – Working the Relationship Between Fire & Invasive Species

10:25-10:45 AM Networking Break

10:45 – 11:45 Round Robin Rotations at Venue

Plant ID

CISMA/LAP

Fire/PBA

11:45-12:30 Lunch

12:30-2:30 Round Robin Rotations at Site

Hack & Squirt/Basal Bark Mixing & Application

Foliar/Cut Stump Mixing & Application

Site Walk Through & Discussion

2:30-3:00 PM Wrap Up Panel & Evaluations

Circular1204

Help Protect Florida’s Natural Areas from Non-Native Invasive Plants1 S. F. Enloe and K. A. Langeland2

The Problem Weeds in Natural Areas The Need for Natural Areas Weeds are undesirable plants. Homeowners battle weeds in their lawns, gardens, and ponds. Weeds are considered More than one-half of Florida’s land area is in agricultural unsightly in parks and playgrounds. Weeds interfere with or urban land uses, and native habitats are continually transportation and can cause hazardous conditions along being lost. Continued urbanization is an inevitable conse- highways, railroads, and waterways. Foresters control weeds quence of increasing population, and food production by to enhance the growth of commercial forests. Billions of agriculture is essential. However, preserving and protecting dollars are spent annually to manage weeds. Florida’s native habitats for historical significance and to protect native species, water quality, and water quantity Non-native plants are those that are introduced to a region is also essential. Natural areas have been designated on outside of their range of natural dispersal. Naturalized federal, state, county, city, and private lands (Figure 1). non-native plants are those that reproduce and sustain populations outside of cultivation in the region where they were introduced. Non-native invasive plants are those that form self-sustaining and expanding populations within plant communities with which they were not previously associated and have ecological impacts. Non-native invasive plants are weeds in natural areas because they displace native plants and associated wildlife, including endangered species, and can alter natural processes such as fire and water flow.

Naturalists recognized potential problems with non-native plants many years ago. In 1920 Charles Torrey Simpson, Florida’s pioneer naturalist, wrote, “There are the adventive plants, the wanderers, of which we have, as yet, compara- Figure 1. Designating certain lands to be managed (or restored) as tively few species; but later, when the country is older and natural areas is one method of protection for native plant and animal more generally cultivated, there will surely be an army of communities.

1. This document is Circular1204, one of a series of the Agronomy Department, UF/IFAS Extension. Original publication date February 1998. Revised June 2015 and August 2018. Visit the EDIS website at http://edis.ifas.ufl.edu.

2. S. F. Enloe, associate professor; and K. A. Langeland, retired professor; Agronomy Department, Center for Aquatic and Invasive Plants, UF/IFAS Extension, Gainesville, FL 32611.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county’s UF/IFAS Extension office. U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension. them.” As predicted, problems associated with non-native plants have increased through the years and non-native invasive plants are now a growing concern to scientists and land managers. Thirty-one percent (about 1,499) of the plant species growing on their own without cultivation in Florida are non-native (Wunderlin and Hansen 2018), and some of these have become serious problems for land managers. For example, from 1997 to 2014, over $129 mil- lion was spent spent by State of Florida agencies to control invasive plant species in upland habitats alone.

Regulated Plants Federal and state laws were passed beginning in the 1970s to prevent further spread or importation of weeds that Figure 3. Brazilian pepper tree (Schinus terebinthifolius) was introduced to Florida in the 1840s as a cultivated ornamental. It is an extremely pose an economic threat to agriculture and navigation. invasive plant that invades fallow farmland, pinelands, and hardwood These laws now restrict possession, transport, or sale of hammocks of south and central Florida, and mangrove forests as far certain plants known to interfere with agroecosystems, north as Levy and Duval Counties. It is listed as a noxious weed by native ecosystems, the management of ecosystems, or cause FDACS. injury to public health. Weeds are listed in the United States Department of Agriculture’s (USDA) Federal Noxious Weed List and the Florida Department of Agriculture and Consumer Services’ (FDACS) Florida Noxious Weed List. Plants that occur on these lists and may occur on private property in Florida include cogongrass (Imperata cylindrica, Figure 2), Brazilian pepper tree (Schinus terebinthifolius, Figure 3), Australian pine (Casuarina spp., Figure 4), tropi- cal soda apple (Solanum viarum, Figure 5), catclaw mimosa (Mimosa pigra, Figure 6), Australian paperbark (Melaleuca quinquinervia, Figure 7), Chinese tallow (Sapium sebiferum, Figure 8), Old World climbing fern (Lygodium microphyl- lum, Figure 9), carrotwood (Cupaniopsis anacardioides, Figure 10), air potato (Dioscorea bulbifera, Figure 11), and skunk vine (Paederia foetida, Figure 12). In addition to plants that are regulated at the federal and state levels, many Florida counties and cities have ordinances that prohibit planting or require removal of non-native plant species.

Figure 4. Australian pine (Casuarina equisetifolia) was introduced to Florida in the late 1800s and planted extensively in the southern half of the state. It is salt-tolerant and invades pinelands, sandy shores, and front-line dunes where it produces dense shade, litter accumulation, and displaces native vegetation. It is listed as a noxious weed by FDACS.

Figure 2. Cogongrass (Imperata cylindrica) has invaded many habitats such as sandhills, flatwoods, grasslands, swamps, river margins, and dry sand dunes throughout Florida and other southeastern states. It is listed as a noxious weed by FDACS and USDA.

Help Protect Florida’s Natural Areas from Non-Native Invasive Plants 2 Figure 5. Tropical soda apple (Solanum viarum), first collected from Florida in 1988, is now a common weed on 500,000 acres of pastures, roadsides, ditchbanks, cultivated land, and natural areas. It is listed as Figure 8. Chinese tallow (Sapium sebiferum), sometimes called a noxious weed by FDACS and USDA. popcorn tree, has been considered an invasive pest plant in the Credits: Jeff Mullahey Carolinas since the 1970s and is expanding its range on the US Gulf Coast through Florida. It is widely dispersed by birds and thrives in undisturbed areas such as closed conopy forests, bottomland hardwood forests, shores of water bodies, and sometimes on floating islands. It is listed as a noxious weed by FDACS.

Figure 6. Catclaw mimosa (Mimosa pigra) is a sprawling, prickly shrub that was first identified in Florida in 1953 and now occurs on 1,000 acres of river floodplain, swamp forest, and lake margins in Broward, Palm Beach, Marin, St. Lucie, and Highlands counties. It is listed as a noxious weed by FDACS and USDA. Figure 9. Old World climbing fern (Lygodium microphyllum) aggressively invades cypress swamps and tree islands in south Florida and carries both wildfires and prescribed burns through natural barriers. It is listed as a noxious weed by FDACS.

Figure 7. Melaleuca, or Australian paperbark (Melaleuca quinquenervia), once widely planted in Florida, now forms dense thickets and displaces native vegetation on 391,000 acres of wet pine flatwoods, sawgrass marshes, and cypress swamps in the southern part of the state. It is listed as a noxious weed by FDACS.

Help Protect Florida’s Natural Areas from Non-Native Invasive Plants 3 Figure 12. Skunk vine (Paederia foetida) invades native plant Figure 10. Carrotwood (Cupaniopsis anacardioides) is a popular communities in Florida and can create dense canopies leading to the landscape tree throughout southern Florida. It produces large crops of death of native vegetation. The plant emits a foul odor, especially seed, which are eaten and transported by birds. It is now naturalized when the leaves are crushed. It is listed as a noxious weed by FDACS. on spoil islands and in tropical hammocks, pinelands, mangrove swamps, cypress domes, scrub, and coastal strand communities. It is EPPC List of Non-native Invasive Species listed as a noxious weed by FDACS. The Florida Exotic Pest Plant Council (FLEPPC) has listed species considered to be most invasive or potentially invasive in Florida. Category I plants on this list are con- sidered to be non-native invasive plants that are currently disrupting native plant communities in certain areas or throughout the state. Category II plants have the potential to disrupt native plant communities. While many plants on this list are also included on prohibited lists, the FLEPPC list itself does not carry statutory authority. Examples of

Figure 11. Air potato (Dioscorea bulbifera) can climb high into tree canopies and engulf surrounding vegetation. It is listed as a noxious weed by FDACS.

Figure 13. Earleaf acacia (Acacia auriculiformis), a messy tree in landscapes, invades disturbed areas as well as pinelands, scrub, hammocks, and pine rocklands in south Florida. It is listed as a FLEPPC Category I species.

Help Protect Florida’s Natural Areas from Non-Native Invasive Plants 4 FLEPPC Category I plants (in addition to the ones already listed as prohibited) include earleaf acacia (Acacia auriculi- formis, Figure 13), bischofia Bischofia( javanica, Figure 14), and Chinaberry (Melia azedarach, Figure 15). The FLEPPC list is modified as merited by new observations. Current and past FLEPPC Invasive Plant Lists are available on the FLEPPC website (http://www.fleppc.org).

In Our Own Back Yards Non-native plants have been introduced as landscape ornamentals, aquarium plantings, agricultural crops, and by accident (Figure 16). They now exist in our landscapes, and some are still sold commercially. Invasive non-native plants growing in proximity to natural areas are a source of invasion. Seeds and spores can be spread by birds, animals, wind, and yard trimmings. The IFAS Assessment of Non- Native Plants in Florida’s Natural Areas was developed by a sub-committee of the interdepartmental UF IFAS Invasive Plants Working Group. The purpose of the IFAS assessment Figure 14. Bischofia Bischofia( javanica) is a weedy tree in landscapes. It is to determine the invasiveness (or potential) of plant spe- is common in old fields and disturbed wetland sites and also invades cies that are recommended for uses such as landscaping and intact cypress domes and tropical hardwood hammocks of south to provide IFAS personnel with guidelines when making Florida. It is listed as FLEPPC Category I species and its use has been recommendations for the use of non-native plants species. discouraged by the FNGLA. Conclusions of the IFAS Assessment for many species can be found at: http://plants.ifas.ufl.edu/assessment. These conclusions can be used as guidelines by homeowners when selecting plants for landscaping. What Can We Do? Learn to Recognize Florida’s Non-native Invasive Plants Not everyone will want to learn to identify the entire list of invasive plants in Florida—at least not right away. A good start is to identify plants on your own property or plants sold in local nurseries, and determine if any are considered invasive. Most non-native invasive plants are included in various plant identification field guides, horticultural books, and botanical keys. Your County Cooperative Exten- sion Office can assist with plant identification. A handbook, SP 257 Identification and Biology of Non-Native Plants in Florida’s Natural Areas Second Edition, is available for sale from the IFAS Extension Bookstore at http://ifasbooks.ufl. edu [Ph: (352) 392-1764]. Figure 15. Chinaberry (Melia azederach) occurs primarily in disturbed areas such as rights-of-way and fencerows and has begun invading floodplain hammocks, marshes, and upland woods, particularly in Prevention north Florida. It is listed as FLEPPC Category I and its use has been When landscaping, do not use plants that have potential discouraged by the FNGLA. to be invasive in natural areas. Local land managers, park biologists, and county governments can provide information on invasive plants that are the greatest problem locally. At the University of Florida, long-range planning

Help Protect Florida’s Natural Areas from Non-Native Invasive Plants 5 policy prohibits the use of many invasive species for future Randall, J. M., and J. Marinelli. 1996. Invasive plants: Weeds landscaping of its properties, and the University of Florida of the global garden, Handbook #149. New York: Brooklyn uses the EPPC Category I plant list as a guideline. Botanic Garden, Inc.

Remove Non-native Invasive Plants from Simberloff, D., D.C. Schmitz, and T.C. Brown (eds.). 1997. Your Property Strangers in paradise: Impact and management of nonspecies in Florida. Washington, D.C: Island Press. Removing non-native invasive plants from private property can eliminate a major source of invasion into natural areas. Whitney, E., D. B. Means, and A. Rudloe. 2004. Priceless Many invasive plants, such as skunk vine, are also weeds in Florida: Natural Ecosystems and Native Species. Sarasota, FL: private landscapes. Others, such as carrotwood, may serve Pineapple Press. a function in the private landscape (as a shade tree, for example). Removal of these plants may seem like a sacrifice for the property owner, but this loss can be a short-term problem. The plant removal will be of long-term, far- reaching benefit to Florida’s natural areas.

Stumps of trees that are cut down should always be treated with an appropriate herbicide to prevent regrowth. After removal, invasive non-native plants can be replaced with native plants or with non-native plants that are not invasive. Information on how to control specific non-native invasive plants and suggestions for non-invasive plants to replace them with can be obtained from County Cooperative Extension offices.

Non-native invasive plants that are not removed from Figure 16. The origins of some non-native plants transported to Florida, either by accident or intentionally. private property should be contained as carefully as possible, especially if the land is in proximity to sensitive natural areas. Carefully dispose of trimmed material from Share this Information invasive plants, especially material with attached seeds or spores, or plant parts capable of vegetative reproduction, The effort to protect Florida’s public lands from non-native such as stems of oyster plant (Rhoeo spathacea). Volunteer invasive plants will require cooperation among private to remove invasive plants from local natural areas under property owners, public land managers, elected officials, the guidance of the natural area manager. Activities such and others. Share this information with your neighbors to as Pepper Busting and Air Potato Roundups are often get the ball rolling and keep it rolling. conducted for this purpose. References Learn More Wunderlin, R. P., B. F. Hansen, A. R. Franck, and F. B. The following publications provide additional information Essig. 2018. Atlas of Florida Plants. [S. M. Landry and K. N. about natural areas and problems caused by non-native Campbell (application development), USF Water Institute.] invasive plants in Florida and around the world: Institute for Systematic Botany, University of South Florida, Tampa. http://florida.plantatlas.usf.edu/ Collard, S. B., III. 1996. Alien invaders: The continuing threat of exotic species. New York: Franklin Watts. Simpson, Charles Torrey. 1920. In Lower Florida Wilds. New York: G. P. Putnam’s Sons. p. 164 Cronk, Q. C. B., and J. L. Fuller. 1995. Plant invaders. London: Chapman and Hall.

Luken, J. O., and J. W. Thieret (eds.) 1997.Assessment and management of plant invasions. New York: Springer.

Help Protect Florida’s Natural Areas from Non-Native Invasive Plants 6 SFE Fact Sheet 2019-2 Terrestrial Invasive Plants and Fire Jennifer Fill & Raelene Crandall Invasive plants complicate management on lands where fire is used to maintain native communities. Invasive species can make it difficult to achieve prescribed fire objectives (for example, by changing fire intensity and fuel continuity), especially when they are resilient to fire.

Stages of Invasion Invasive plants can be affected by fire at one or more stages of the invasion process: 1) colonization by seed or vegetative propagules, 2) survival and reproduction, 3) growth or increase in density by spreading vegetatively or by seed (low density, but increasing), and 4) dominance, in which a species is not only very abundant but also suppresses other species.

Invasive plants vary in their sensitivity to fire during plant relationships can change over time and are influenced the invasion process. Some species are sensitive to fire by the environmental context, including the native community management at all stages. Both seeds and non-sprouting assemblage, soil fertility and hydrology, and presence of pests adult plants experience high mortality after fire such that the and pathogens. species is unable to reproduce, spread, and become dominant Invasive plants are a concern in fire management when they in fire-frequented environments. In other cases, invasive influence fire regimes. Some species, such as cogongrass species are resilient to occasional fire. Fire can stimulate (Imperata cylindrica), produce abundant biomass that greatly germination in these species and promote spread, but fires increases fuel loading and generates intense fires. Other that occur too frequently or before plants begin to reproduce species, such as Chinese tallow (Triadica sebifera), shade can kill adult plants, deplete the seed bank, and prevent out understory fine fuels or produce dense litter that holds dominance at a site. Some species are unaffected or even moisture and suppresses fire. Typically, the effects that plants promoted by fire. These species are often the most difficult have on the fire regime will increase as their density increases. to control, because they tend to survive fire by resprouting followed by rapid growth and sometimes abundant seed The following table summarizes our current knowledge of production that allows them to quickly gain dominance. Fire- the fire ecology of several common invasive plants in fire- frequented habitats of the southeastern US.

1 Seedlings can establish on burned and unburned sites unburned and burned on establish can Seedlings canopy open and nutrient in high best Grows conditions Chemicals in bark, leaves, and seeds inhibit of growth plants nearby in close varieties different but sterile be to Thought crosspollinate can proximity are so they fire, to vulnerable more are trees Small areas burned frequently invade to unlikely growth seedling reduce can burning spring Annual fire from them protects trees in older bark Thick Shortlived seed bank fires summer late to vulnerable More germination seed promote fires Winter 20 years up to for viable are Seeds at and sizes small at fire to vulnerable More low densities sites, burned frequently colonize to likely Less colonize can but undisturbed, are that those especially areas burned recently adults than vulnerable more are Seedlings of in a variety establish that seeds abundant Produces areas disturbed especially conditions, year of time any at intensely Burns Heavy accumulation litter via spreads and taproot a deep develops Quickly rhizomes belowground plants other of germination inhibits litter kudzu Dense March annual of 3 years after increased Abundance fires in sandhills (prior vine to emergence) litter under buried when bulbil viability Longer wind by spread Spores • • • • • • • • • • • • • • • • • • • • • • Established plants resprout from from resprout plants Established roots and base establishment seedling postfire High that seeds winddispersed many from ground open on germinate resprout older and 2 years Seedlings up to seedlings and seeds kills Fire old 1 year Resprouts vigorously from roots and base Canopy is not flammable crown root from Resprouts seedbank large from in soil Regenerates fire by promoted Populations tolerance heat limited have Seeds stems aboveground from Resprouts crown and root Burned individuals might produce fewer seeds roots or crowns root from Resprouts rhizomes from resprouts Quickly Able to outcompete native species fire after crown root subsurface from Resprouts fire after seed promote could heating Soil germination tubers from Resprouts survival higher bulbils have Larger fire after fire after rapidly Resprouts • • • • • • • • • • • • • • • • • • • • Ladder fuels increase increase fuels Ladder fire potential crown High content moisture and intensity fire reduces duringspread summer could in winter fuels Dry intensely burn increase fuels Ladder fire potential crown increase fuels Ladder fire potential crown break could fern of Pieces fires spot start and off • • • • • • No effect, but could produce produce could but effect, No smoketoxic when burned No particular effect particular No dense under fuel of Lack not does so fire stands spread effect particular No stands closed-canopy Dense does so fire fuels fine limit not spread under conditions Moist fire reduce stands dense intensity and spread and intensity fire Increases spread Effects on fire on Effects response Post-fire characteristics Additional edges, open areas open edges, floodplains, uplands dry sites to moist in and areas zones riparian old fields, open open fields, old areas grasslands dry sites to moist upland habitats areas, disturbed dry soils to moist swamps Environments it Environments invades Tree forests, Disturbed Tree Streams, Grass areas, Disturbed Vine Open or disturbed Tree forests, Disturbed Shrub Bottomlands, Shrub Disturbed areas, Shrub and Riparian Vine edges, Forest Vine and habitats Moist form

) ) ) ) ) var. ) ) ) ) ) Ailanthus altissima Ailanthus Pyrus calleryana Pyrus sebifera Triadica Lespedeza cuneata Schinus terebinthifolia sinense Ligustrum cylindrica Imperata montana Pueraria bulbifera Dioscorea Lygodium Tree of heaven Tree ( Callery pear Callery ( tallow Chinese ( lespedeza Sericea ( Brazilian pepper ( privet Chinese ( Cogongrass ( Kudzu ( potato Air ( fern climbing world Old ( microphyllum lobata Species Growth

2 What is the stage Early - Most plants are young/not reproductive of invasion? Late - Plants are established and reproducing

Small - Few plants scattered across the landscape What is the size of invasion? Large - Invasive dominating or nearly dominating across the landscape

No effect

How does the invasive Negative - invasive decreases fire frequency species affect fire? and intensity Positive - invasive increase fire frequency and intensity

Reseeder – regeneration is by seed only; adult plants do not survive fires How does the invasive Resprouter – regeneration is primarily by species regenerate resprouting from root crowns after fire? Reseeder/Resprouter – both regeneration methods are common after fire

No effect Negative - fire decreases density of invasive species How does fire affect Negative, but depends on burn season - fire the invasive species? decreases density of invasive species when sensitive (i.e., when plants are reproducing Positive - fire increases density of invasive species

Zero bold questions, No - But proceed with caution Do other methods and continue monitoring invasive density and spread need to be considered instead of or in addition One or more bold answers, Yes - Consider to prescribed fire? controlling invasive prior to or in conjunction with fire

If one or more questions have a bold answer, carefully consider the benefits of applying prescribed fire prior to reducing invasion size and extent.

3 Key Management Considerations

Fire management can target fire-resilient species as seeds (e.g., cogongrass) or decreasing (e.g., Brazilian pepper) or as adults. Fire can be used to kill some seeds on the soil intensity and spread. surface or those still on reproducing plants. Mature plants Burning when populations are sensitive to fire will also reduce that resprout after fire are rarely killed by a single fire. Often recovery after fire. For instance, it is recommended, when very frequent (annual) fires can slow population spread but possible, to burn when plants are flowering or producing will likely not eliminate invasive species unless populations seeds to reduce seed production and germination after fire. are low-density or composed of mainly young plants. When Ultimately, outcomes will depend on habitat type, coexisting densities are high, mechanical or chemical removal methods species, and stage of invasion. Each invasion should be should be considered (e.g., mature kudzu vines), especially carefully and individually considered before management if the invasive is known to alter the fire regime by increasing actions are taken.

Additional Resources More specific resources for invasive plant management recommendations can be found by contacting your local/state Cooperative Extension office and by searching on the US Forest Service TreeSearch search engine (https://www.fs.usda.gov/treesearch/).

High Cogongrass Infestation Low Cogongrass Infestation References Brooks, M. and M. Lusk. 2008. Fire Management and Invasive Plants: a Warrix, AR, Marshall, JM (2018) Callery pear (Pyrus calleryana) response Handbook. United States Fish and Wildlife Service, Arlington Virginia, 27 pp. to fire in a managed prairie ecosystem. Invasive Plant Science and Crandall RM, Knight TM (2018) Role of multiple invasion mechanisms and their Management 11:27-32 interaction in regulating the population dynamics of an exotic tree. Journal Stevens, JT, Beckage, B (2009) Fire feedbacks facilitate invasion of of Applied Ecology 55:885-894 pine savannas by Brazilian pepper (Schinus terebinthifolius). New Grace JB, Smith MD, Grace SL, Collins SL, Stohlgren TJ (2001) Interactions Phytologist 184:365-375 between fire and invasive plants in temperate grasslands of North Stevens JT,, Beckage B (2010) Fire effects on demography of the invasive America. In: Galley KEM, Wilson TP (eds) Proceedings of the Invasive shrub Brazilian pepper (Schinus terebinthifolius) in Florida pine Species Workshop: the Role of Fire in the Control and Spread of Invasive savannas. Natural Areas Journal 30:53-63 Species. Fire Conference 2000: the First National Congress on Fire Ecology, USDA Fire Effects Information System. https://www.feis-crs.org/feis/ Prevention, and Management. Miscellaneous Publication No. 11, Tall Zouhar K, Smith JK, Sutherland S, Brooks ML (2008) Wildland fire in Timbers Research Station, Tallahassee, FL, pp 40–65 ecosystems: fire and nonnative invasive plants. Gen. Tech. Rep. RMRS-GTR- Guthrie, SG Crandall RM, Knight TM (2016) Fire indirectly benefits fitness in 42-vol. 6. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky two invasive species. Biological invasions 18:1265-1273 Mountain Research Station

Authors: Jennifer Fill & Raelene Crandall For more information on the Southern Fire Exchange, visit www.southernfireexchange.org or email [email protected]. For additional information on the reciprocal effects of invasive plants and fire, see https://www.feis-crs.org/feis/ The Southern Fire Exchange is funded through the Joint Fire Science Program, in agreement with the United States Forest Service, Southern Research Station. This institution is an equal opportunity provider.

4 SS-AGR-260

Herbicide Application Techniques for Woody Plant Control1 Jason Ferrell, Stephen Enloe, and Brent Sellers2

The encroachment of trees and other woody plants into can be tricky to manage, and it is difficult to generate a fire pastures, fencerows, ditch banks, rights-of-way, and other with sufficient heat capacity to kill most hardwood species areas is a common occurrence. These woody species can along fencerows, ditch banks, and other sites with low plant be particularly troublesome and require control since they density. will compromise fence integrity, vehicle safety, impede canal drainage, interfere with transmission of electricity. Herbicides are often the most effective and inexpensive Additionally, some species (such as cherry trees) are highly means of controlling woody plants. There are several poisonous to livestock. The aim of this publication is to application techniques that can be used to control trees detail the techniques for the removal of woody plants. For and brush of various sizes. Not all brush species are equally information on controlling similar species in natural areas susceptible to herbicides. Therefore, results may vary for or in forestry settings, consult UF/IFAS publications SP242, any of these application methods, relative to brush size and Integrated Management of Nonnative Plants in Natural Areas species. Each application technique will be subsequently of Florida (http://edis.ifas.ufl.edu/wg209) and Circular discussed. 1477, Primer on Chemical Vegetation Management in Florida Pine Plantations (http://edis.ifas.ufl.edu/fr160). Foliar Application Foliar application directs an herbicide/water mixture Control of woody perennials can be difficult, but several directly onto the leaves of a plant (Figure 1). This technique control techniques are available. Mowing is a commonly can be highly effective on smaller species (6 to 8 feet in used control procedure for small brush because the equip- height). Auxin-type herbicides (such as triclopyr) are ment is readily available and the results are immediate. generally most effective early in the season, while enzyme- However, this method generally provides only short-term inhibiting herbicides (imazapyr and others) are most success because it leaves live stumps and root-stocks that effective in the late summer or fall. Glyphosate is most re-sprout. Mowing some species, like Chinese tallow, wors- effective in late summer or fall, prior to change in leaf color ens the situation by replacing a single stemmed plant with a for deciduous species. stump with multiple re-sprout stems. Another strategy that can reduce some troublesome species is fire. However, fire

1. This document is SS-AGR-260, one of a series of the Agronomy Department, UF/IFAS Extension. Original publication date January 2006. Revised December 2015. Reviewed December 2018. Visit the EDIS website at https://edis.ifas.ufl.edu for the currently supported version of this publication.

2. Jason Ferrell, professor; Stephen Enloe, associate professor, Agronomy Department; and Brent Sellers, associate professor, Agronomy Department, UF/ IFAS Range Cattle Research and Eduation Center; UF/IFAS Extension, Gainesville, FL 32611.

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication do not signify our approval to the exclusion of other products of suitable composition.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county’s UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension. Basal applications will not provide rapid control. Herbicide injury is often not observed for several weeks after treat- ment, and complete control may require several months. Additionally, basal treatment is not effective on older trees greater than six inches in diameter or trees with very thick bark. For these situations, other application techniques should be employed.

Figure 1. Foliar application with a backpack sprayer. Credits: Stephen Enloe, UF/IFAS Adequate control with foliar applications can be difficult to accomplish. This is because complete coverage of all foliage is essential for control, but over-application (which leads to spray runoff) will reduce effectiveness. Therefore, foliar applications commonly require multiple follow-up treatments before control is accomplished. It is important to control spray drift when making foliar applications. Certain desirable hardwood and crop species are highly sensitive to spray drift and can be inadvertently damaged. It is also advisable to include a tracer dye with the spray solution to ensure that some plants are not sprayed twice while others Figure 2. Basal bark application with herbicide/oil mixture. are missed entirely. Credits: Stephen Enloe, UF/IFAS

What about mowing before treatment? Mowing decreases Hack and Squirt foliage while maintaining a large root mass, making control The hack-and-squirt technique is ideal for control of large even more difficult. If plants have been mowed, it is impor- trees that cannot be managed with basal applications. This tant to allow them to regrow to a height of 3 or 4 feet before method requires that you use a machete or hatchet to cut herbicide application. through the thick bark and into the sapwood. The hacks should be made at a downward angle of approximately Basal Application 45 degrees. This will create a “cup” to hold the herbicide solution. If the hack does not hold herbicide solution, the Basal application combines the herbicide with an oil treatment will not be effective. Most labels specify 0.5 to 1.0 penetrant and applies the mixture directly to the bark of ml of solution per hack. This is important to note, as small a standing tree. For trees that are less than 6-inches in spray bottles commonly sold in garden supply stores may diameter and have smooth bark, this method is frequently apply as much as 3.5 ml per stroke. This makes accurate successful. However, it is important that the lower 12 to 18 application very difficult, but the most important aspect is inches of the stem be treated on all sides with the herbicide/ not to overfill the hack. The recommended spacing of hacks oil mixture (Figure 2). Adequate coverage is essential, since around the circumference of the tree is specified on the treating only one side of the stem will result in controlling herbicide label and may be described as slightly overlap- only half of the tree. Basal applications can be made any ping, continuous, or evenly spaced. (Figure 3) The addition time of the year, but control may be reduced when trees of a basal oil is not recommended for this procedure. are flushing new growth in the spring. Winter is often the easiest time to do basal treatments as temperatures are This method of application is advantageous because it is cooler and many tress and surrounding herbaceous plants highly selective and injury to surrounding species is not are dormant. common. It can also be done at any time during the year, but effective treatment of some species in the spring can be

Herbicide Application Techniques for Woody Plant Control 2 reduced because of heavy sap flow pushing the herbicide from the cut surfaces. Finally, the hack and squirt method should only be used where dead standing trees are accept- able from an aesthetic and safety standpoint. Therefore, it is not recommended along roadsides or in parks where hazard trees cannot be tolerated.

Figure 4. Application of herbicide to larger cut stumps only requires treatment of the outer edge. Credits: Stephen Enloe, UF/IFAS

Figure 3. Hack-and-squirt application technique. Credits: Stephen Enloe, UF/IFAS Cut Stump This technique is employed after cutting a tree to eliminate, or greatly reduce, resprouts from the stump or lateral roots. The herbicide should be applied to the cut surface as quickly as possible after the sawdust has been removed. If applied immediately, an herbicide/water solution is suf- ficient. If herbicide treatment is delayed and the cut surface has begun to dry, an herbicide/basal oil mixture must be used instead and applied to the top and around the collar of the stump.

For stumps greater than 3 inches in diameter, thoroughly wet the outer edge while avoiding herbicide runoff (Figure 4). This is because the only living tissue in larger trees is Figure 5. Application of herbicide to smaller stumps requires complete around the outer edge. Covering the entire cut surface will coverage. require more herbicide, most of which will provide little Credits: Stephen Enloe, UF/IFAS effect. For smaller stems it is appropriate to cover the entire cut surface (Figure 5). For this procedure, herbicides can be applied using a backpack sprayer, squirt bottle, or paint brush. Regardless of how the herbicide is applied, a tracer dye should be included to ensure treatment of all individual stumps.

Herbicide Application Techniques for Woody Plant Control 3 Table 1. Recommended herbicides for each application procedure. Herbicide Application Rate Comments Foliar Application Imazapyr 1–3% Excellent control of sweetgum and maples. Use higher rates for oaks and (Arsenal, others) cherry. A non-ionic surfactant is required. Glyphosate 5–8% Cover as much of the foliage as possible and spray until wet. If the brush has (Several) been cut, delay application for approximately 1 year. Retreatment is commonly required control. triclopyr + 2,4-D 1–1.5% For control of various herbaceous and woody species. This product contains (Crossbow) 2,4-D ester; precautions to manage drift must be employed. Repeat applications are often required. Triclopyr ester 0.5–2% Best when applied in late spring or early summer. If the brush has been cut, (Remedy Ultra, others) delay application for approximately 1 year. Thoroughly wet all leaves, but not Triclopyr + fluroxypyr 2–4 qt/100 gal of spray to the point of runoff. (Pasturegard HL) Aminocyclopyrachlor Method 8–16 oz/100 gal of For best results, apply near the top of the tree and allow the spray to trickle 240 SL spray down into the canopy. Full coverage of canopy is necessary, but do not allow runoff. Apply with 1% v/v methylated seed oil (MSO). Aminopyralid Milestone 0.25–0.75% solution For control of a wide variety of woody plants. For best results, mix with glypohosate (3-5%) and imazapyr (0.5%) or triclopyr at 1% plus a surfactant. Do not exceed 7 oz/A of Milestone. Basal Bark Imazapyr 8–12 oz/gal Best for trees less than 4 inches DBH (diameter at breast height). Be aware that (Stalker, others) imazapyr is highly active in the soil. If desirable plants are near to a treated individual, it is possible for the herbicide to wash off into the soil and injure or kill the desirable plant. Make sure to choose an imazapyr product that is soluble in basal oils. Aminocyclopyrachlor Method 10–20% solution Best for trees less than 6 DBH. Spray until run-off at the ground line is 240 SL noticeable. This herbicide significant soil activity, so be aware that desirable trees in the vicinity may be injured by these applications. Triclopyr ester 100% Pathfinder is a “ready to use” product that is formulated and dosed correctly for (Pathfinder) this type of application. Apply Pathfinder at 100% strength as directed. Triclopyr ester 25% + 75% basal oil Best for trees less than 6 inches DBH. Generally most effective 6 weeks prior to (Remedy Ultra or others) leaf expansion, until 2 months after. Most effective on trees with smooth bark. Triclopyr + fluroxypyr 25% + 75% basal oil Thick bark trees may require retreatment. These herbicides have little or no soil (Pasturegard HL) activity. Hack-and-Squirt Imazapyr 4 lb/gal 6 oz/gal One hack per 3 inches DBH. (Arsenal AC) Triclopyr amine 50–100% One hack per 3 or 4 inches DBH. Apply 0.5 ml undiluted herbicides or 1 ml of (Garlon 3A, others) 50% solution in water. Hexazinone 100% One hack per 4 inches DBH. Use undiluted herbicide. (Velpar) Glyphosate 50% 1 ml per 2 or 3 inches DBH, applied below the branches. For larger trees, best (several) results are observed from applying glyphosate in a continuous frill around the stem. Aminopyralid (Milestone) Make a series of slightly overlapping hacks around the trunk. Apply 1 ml of the solution per hack.

Herbicide Application Techniques for Woody Plant Control 4 Herbicide Application Rate Comments Cut Stump Imazapyr 6 oz/gal (for Arsenal AC) Apply to the top and side of a freshly cut stump. Garlon 3A is excellent for this (Arsenal AC or Stalker) or use. If surface of stump has began to dry prior to herbicide treatment, apply 8-16 oz/gal (for Stalker) Chopper or triclopyr ester product in basal oil or recut the stump and apply to Triclopyr amine 50–100% in water the freshly cut surface. Garlon 3A will not effectively mix with basal oils. (Garlon 3A) Triclopyr ester 25% solution in water (Remedy Ultra or others) or basal oil Triclopyr + fluroxypyr 25% solution in water (Pasturegard HL) or basal oil Aminocyclopyrachlor Method 5–10% solution in basal Spray the stump surface and thoroughly wet the cambium layer all the way 240 SL oil around. Glyphosate 50–100% Apply to cut stumps immediately after cutting. Glyphosate is not effective on (several) stumps that have started to dry after cutting. If immediate treatment is not possible, other herbicides should be selected since glyphosate will not mix with basal oils. Aminopyralid (Milestone) 10% Apply solution to cambium area around the entire circumference of the stump. Apply immediately after cutting.

Herbicide Application Techniques for Woody Plant Control 5 Contacts

UF/IFAS Extension Florida Invasive Species Partnership

Alicia Halbritter Emily Bell Baker County (352) 846-2374 904-259-3520 [email protected] [email protected] https://www.floridainvasives.org/plants.cfm

Tyler Pittman Marion County 352- 671-8400 Alachua Conservation Trust [email protected] Barry Coulliette 904-838-8591 Other counties- [email protected] http://sfyl.ifas.ufl.edu/find-your-local-office/ www.alachuaconservationtrust.org

North Florida Prescribed Burn Association

Barry Coulliette 904-838-8591 [email protected] http://www.northfloridapba.org/

FWC Land Owner Assistance Programs

Lanie Carter 386-234-1030 [email protected] https://myfwc.com/conservation/special- initiatives/lap/