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ENH 1070

Pre- and Postemergence Herbicides for Use Around Palms and Cycads1 Robert H. Stamps, Jeffrey G. Norcini, Timothy K. Broschat and Charles W. Meister2

Palms and cycads are important weeding and, thereby, reduce landscape ornamentals, especially in production costs. In the landscape, pre- Florida. However, as a group, they are and postemergence herbicides can slow growing so it is very important to reduce maintenance costs. optimize growing conditions in order to make their production economical and Disclaimer: Mention of a commercial or proprietary product or chemical does not constitute their establishment in the landscape a recommendation or warranty of the product by rapid. Due, in part, to the length of time the authors or the University of Florida, Institute of Food and Agricultural Sciences, nor does it imply required to produce marketable plants, its approval to the exclusion of other products that weeds frequently become a problem may also be suitable. Products should be used during production. Of course, weeds according to label instructions and safety equipment required on the label and by federal or use valuable water and nutrients that state law should be employed. Users should avoid could otherwise be utilized by these the use of chemicals under conditions that could lead to groundwater contamination. Pesticide crops. In addition, weeds compete with registrations may change so it is the young plants for light. Weeds may also responsibility of the user to ascertain if a release chemicals that inhibit the growth pesticide is registered by the appropriate state of other plants (this is known as and federal agencies for an intended use. allelopathy). Selected palms and cycads Weed management costs in the specifically labeled as tolerant to nursery can be very high if only hand preemergence herbicides are listed in labor is employed. Pre- and Table 1. However, palms as a group postemergence herbicides can tend to be somewhat unpredictable in significantly reduce the need for hand their phytotoxic responses to herbicides.

1 This document is ENH 1070, one of a series of the Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date August 2007. Visit the EDIS Web Site at http://edis.ifas.ufl.edu. 2 Robert H. Stamps, Professor, Mid-Florida Research and Education Center-Apopka, Jeffrey G. Norcini, Associate Professor, North Florida Research and Education Center-Quincy, Timothy K. Broschat, Professor, Ft. Lauderdale Research and Education Center; and Charles W. Meister, Scientist, Pesticide Research Lab-Gainesville.

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 nondiscrimination 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 extension publications, contact your county Cooperative Extension service. U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Larry Arrington, Dean. This may be due to genetic and/or herbicides (by trade name, or active developmental differences among ingredient where more than one plants. Therefore, use these products product has the same active ingredient) with caution and on a small scale at in columns. If one of the plants is listed first. This is especially true for palm on a herbicide label there will be a letter seedlings. In fact, some herbicide labels in the box where the crop row and the specifically prohibit the use of the herbicide column intersect. The letters products on seedlings. indicate: C = labeled for use on container-grown plants, F = labeled for Some herbicides (such as use on field-grown (in-ground) plants, L BroadStar™, Corral®, Dimension®, = labeled for use in the landscape and X Granular Herbicide 75, Kansel+®, OH2®, = the herbicide should not be used on oryzalin, Preen® Plus, PrePair®, the crop. Please note that none of the Showcase™, Snapshot™ TG, Treflan™, preemergence herbicides are labeled XL®) may include a statement on their for use in enclosed shadehouses or labels that allows their use on an greenhouses. Also note that landscape ornamental species not listed on the areas may be differentiated into label, provided that the user makes a subgroups such as commercial, trial application of the product at the industrial, residential and roadside, and recommended rate to a small number of that herbicide usage may be limited to plants in order to determine if the one or only some of these landscape product causes injury (phytotoxicity) to planting types. Read each label the tested species. Users should check carefully. for injury for up to 10 months after application since it may take this long The only postemergent herbicides for injury symptoms to develop in specifically labeled for use on palms and palms and cycads. Growers are also one cycad are fluzifop-P-butyl advised to further test the effects of (Fusilade® II, Ornamec®) and multiple applications of any herbicide sethoxydim (Sethoxydim G-Pro, because plants that seemingly are Vantage®). These herbicides will kill tolerant of a single herbicide application many annual and some perennial may exhibit phytotoxicity symptoms grasses; however, they are not effective following a second application (at the on broadleaf weeds and sedges. Check recommended rates and intervals). the labels of these grass herbicides to Regardless, the user assumes determine whether they must be responsibility for any plant damage or applied as directed sprays or can be other liability resulting from the use of sprayed over-the-top of the crop. The any herbicide on plant species not palms and cycad included on the labels recommended on the product label. are listed in Table 2. The locations Product labels may also limit the total where these two products can be used amount of product that can be used on a are indicated in Table 2 by the letter given area per year. designations listed above for Table 1 and the following: G = product is Table 1 lists selected palms and labeled for use on the crop when it is cycads in alphabetical order (by genus) growing in a greenhouse and N = in rows and selected preemergence product is labeled for use in nurseries.

Pre- and Postemergence Herbicides for Use Around Palms and Cycads Page 2 Diquat dibromide (Diquat, The use of a combination of a Reward®), glufosinate-ammonium preemergence and a postemergence (Finale®) and pelargonic acid (Scythe®) herbicide can save labor and extend the are postemergence contact (none or time intervals between herbicide limited translocation) herbicides that applications. generally only kill the above-ground Additional information about portion of the weed. These herbicides these herbicides can be found in are applied as directed sprays just to the “Preemergence Herbicides for Use In weeds (avoid contact with the crop) and Ornamentals” (OH94) and are most effective on annual weeds and “Postemergent Herbicides for Use in weeds without extensive root systems. Ornamentals” (ENH95). Glyphosate-containing products At this time, the authors know of (Glyfos®, RoundUp®, Touchdown®, etc.) no other herbicides that are labeled for are systemic postemergence herbicides use on ornamental palms and cycads, or that are translocated throughout the of palms and cycads other than those plant. They will kill annual and included in Table 1 that are included on perennial broadleaf weeds, grasses and ornamental preemergence herbicide sedges. These products are quite safe labels. Please let us know of any for use as carefully applied directed corrections or additions that need to be sprays around palms. However, should made to this publication (PHONE: injury occur, palms will usually grow 407/884-2034 ext. 164, E-MAIL: out of any symptoms within a couple of [email protected]). months.

Pre- and Postemergence Herbicides for Use Around Palms and Cycads Page 3 Table 1. Palms and cycads tolerant of various preemergence herbicides (C = product is labeled for use on the crop when it is growing outdoors in containers, F = product is labeled for use on the crop when it is growing in the field, L = product is labeled for use on the crop when it is growing in the landscape, X = do not use product on indicated genus, species or hybrid). 1 6 ® 2 5 ® 50DF 2G 3 ® ® G 4 ® ® ®

Pre- and Postemergence Herbicides for Use Around Palms and Cycads Page 4 Table 1. Palms and cycads tolerant of various preemergence herbicides (C = product is labeled for use on the crop when it is growing outdoors in containers, F = product is labeled for use on the crop when it is growing in the field, L = product is labeled for use on the crop when it is growing in the landscape, X = do not use product on indicated genus, species or hybrid). 1 6 ® 2 5 ® 50DF 2G 3 ® ® G 4 ® ® ®

Scientific name ® ® Devrinol Dimension trifluralin + isoxaben trifluralin XL BroadStar™ Corral™ Devrinol Gallery™ Granular Herbicide 75 Kansel+ OH2 oxyfluorfen + oxadiazon pendimethalin Pennant Magnum PrePair Ronstar oryzalin Treflan™ G (Common name) Showcase™ simazine Chamaedorea costaricana C, F, L C, F, L C, F F, L C, F, L C, F, L F, L (bamboo palm, Costa Rican palm) Chamaedorea elegans [synonym Collinia elegans] C, F, L C, F, L C, F, L C, F, L C, F F, L C, F, L C, F, L F, L (parlor palm, neanthe bella palm) Chamaedorea erumpens [see Chamaedorea seifrizii] (bamboo palm) Chamaedorea seifrizii [synonym C, F, L C. erumpens] (bamboo palm) Chamaerops [see Chamaerops humilis] (European fan palm, Mediterranean fan palm) Chamaerops excelsa [see Rhapis excelsa] (lady palm) Chamaerops fortunei [see Trachycarpus fortunei] (windmill palm) Chamaerops humilis (European fan palm, C, F F, L C, F, L C, F Mediterranean fan palm) Chrysalidocarpus lutescens [see Dypsis lutescens] (areca palm) Cocos plumosa [see Syagrus romanzoffiana] (queen palm)

Pre- and Postemergence Herbicides for Use Around Palms and Cycads Page 5 Table 1. Palms and cycads tolerant of various preemergence herbicides (C = product is labeled for use on the crop when it is growing outdoors in containers, F = product is labeled for use on the crop when it is growing in the field, L = product is labeled for use on the crop when it is growing in the landscape, X = do not use product on indicated genus, species or hybrid). 1 6 ® 2 5 ® 50DF 2G 3 ® ® G 4 ® ® ®

Pre- and Postemergence Herbicides for Use Around Palms and Cycads Page 6 Table 1. Palms and cycads tolerant of various preemergence herbicides (C = product is labeled for use on the crop when it is growing outdoors in containers, F = product is labeled for use on the crop when it is growing in the field, L = product is labeled for use on the crop when it is growing in the landscape, X = do not use product on indicated genus, species or hybrid). 1 6 ® 2 5 ® 50DF 2G 3 ® ® G 4 ® ® ®

Pre- and Postemergence Herbicides for Use Around Palms and Cycads Page 7 Table 1. Palms and cycads tolerant of various preemergence herbicides (C = product is labeled for use on the crop when it is growing outdoors in containers, F = product is labeled for use on the crop when it is growing in the field, L = product is labeled for use on the crop when it is growing in the landscape, X = do not use product on indicated genus, species or hybrid). 1 6 ® 2 5 ® 50DF 2G 3 ® ® G 4 ® ® ®

Scientific name ® ® Devrinol Dimension trifluralin + isoxaben trifluralin XL BroadStar™ Corral™ Devrinol Gallery™ Granular Herbicide 75 Kansel+ OH2 oxyfluorfen + oxadiazon pendimethalin Pennant Magnum PrePair Ronstar oryzalin Treflan™ G (Common name) Showcase™ simazine Trachycarpus spp. C, F C, F Trachycarpus fortunei [synonym Chamaerops F, L C, F, L fortunei] (windmill palm) Veitchia merrillii [see Adonidia merrillii] (Adonidia, Christmas palm) Washingtonia C, F C, F Washingtonia robusta (Washington fan C, F, L C, L F, L F, L C,F, L F, L X F, L C, F, L F, L F, L palm, Mexican fan palm) Zamia furfuracea C, F, L (cardboard palm) 1 O-O Herbicide™, Lasar™ 2 Pendulum®, Pre-M®; see individual labels for specific genera and/or species listed. Also, see Corral™, a granular formulation of pendimethalin labeled for use in nurseries. 3 Princep®, Simazine, Sim-Trol® 4 Quali-Pro™ Oryzalin 4 Pro, Surflan®, Vegetation™ Manager Oryzalin 4 Pro 5 Not for use on plants being grown for sale or other commercial use, or for commercial seed production or for research purposes. For use on plants for aesthetic purposes or climatic modifications and being grown in interior plantscapes, ornamental gardens or parks, or on golf courses or lawns and grounds. 6 Preen® Plus, Snapshot™ TG

Pre- and Postemergence Herbicides for Use Around Palms and Cycads Page 8 Table 2. Palms and cycads tolerant of various postemergence herbicides (F = product is labeled for use on the crop when it is growing in the field, G = product is labeled for use on the crop when it is growing in a greenhouse, L = product is labeled for use on the crop when it is growing in the landscape, N = product is labeled for use in nurseries). Scientific name (Common name) fluazifop-P-butyl 1 sethoxydim 2 Arecastrum romanzoffianum [see Syagrus romanzoffiana] (queen palm) Chamaerops [see Chamaerops humilis] (European fan palm, Mediterranean fan palm) Chamaerops fortunei [see Trachycarpus fortunei] (windmill palm) Chamaerops humilis F, G, L, N F, L, N (European fan palm, Mediterranean fan palm) Chrysalidocarpus lutescens [see Dypsis lutescens] (areca palm) Cocos plumosa [see Syagrus romanzoffiana] (queen palm) Cycas revoluta F, G, L, N F, L, N (king sago, king sago palm, sago palm) Dypsis lutescens [synonym Chrysalidocarpus lutescens] F, G, L, N (areca palm) Livistona chinensis F, G, L, N (Chinese fan palm, Chinese fountain palm) Phoenix canariensis (Canary Island date palm) F, G, L, N Phoenix roebelenii F, G, L, N F, L, N (pigmy date palm, miniature date palm) Syagrus romanzoffiana [synonyms Arecastrum romanzoffianum, Cocos plumosa] F, G, L, N F, L, N (queen palm) Trachycarpus fortunei [synonym Chamaerops fortunei] F, G, L, N F, L, N (windmill palm) Washingtonia robusta F, G, L, N (Washington fan palm, Mexican fan palm) 1 Fusilade® II, Ornamec® 2 Sethoxydim G-Pro, Vantage®

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