Combating Scotch Broom CPOP Listserv Discussion

Transcription

1 Combating Scotch Broom CPOP Listserv Discussion Successful application of Milestone in the winter to combat Scotch broom. Summary Treatment of Scotch broom with milestone in the winter has proven to be quite successful. One individual reported a 75-80% mortality and minimum re-sprouting after 9 months of initial application. Their hope is to expand the trial this winter with triclopyr as well as milestone to achieve even better results. However, it was mentioned that several of the chemicals which are effective for controlling broom also can have off-target impacts on desirable native plants. To avoid the negative effects associated with triclopyr, one contributor suggested using goats to combat Scotch broom. "Grazing by goats during active growth of Scotch broom has been used successfully in New Zealand, however it requires several seasons for effective control (USDA). Additionally, it was noted that herbicides are not possible for all organizations (e.g. lands being under conservation covenant), and rather than relying on chemical control it was suggested that increasing community involvement is a major factor in environmental restoration success is possible when people have a connection to the land and a vested interest in long-term management practices. In the end, it is clear that a successful broom control program will require an integrated approach that incorporates multiple strategies and techniques. Suggestions for Scotch broom treatment Cutting larger plants (with diameters greater than your thumb) and pulling smaller ones. Chemically treat Scotch broom using aminopyralid or triclopyr 3A just after flowering, in May. Use heat and flame treatment methods. Goat and sheep grazing. Combating Scotch Broom 1

2 Combatting Scotch Broom Original CPOP Listserv Messages The CPOP Listserv Archive can be found for subscribers at listserv.wa.gov. To subscribe to the CPOP Listserv visit our website at cascadiaprairieoak.org. October 24, 2014 Nathan Johnson (Center for Natural Lands Management) Hi all, I thought I'd share some encouraging results from a small trial we conducted in January to see about the efficacy of treating scotch broom in the winter with milestone. We got about 75-80% mortality and little resprouting after 9 months. Hopefully we'll expand the scope this winter and try triclopyr as well as milestone. Cheers! Nathan Johnson Invasive Species Project Manager Center for Natural Lands Management *The original attachment provided by Nathan Johnson titled Winter Broom Treatment with Milestone is included as Appendix I of this discussion summary. October 24, 2014 Sarah Deumling (The Zena Forest) Nathan, I am just a private landowner without so much knowledge but with lots of Scotch Broom to deal with. What is the recipe? What proportions of what do you mix with the milestone. And is now considered winter time for spraying purposes? Thanks you very much, Combating Scotch Broom 2

3 Sarah Deumling The Zena Forest Willamette Valley Oregon October 25, 2014 Christer LaBrecque (Center for Natural Lands Management) I would advise against winter treatment. Use aminopyralid or triclopyr 3A just after flowering, in May. If you have very large plants - stems just above the ground that are larger than 1.5" in diameter, I'd say mow the patch down asap and then spray whatever re-sprouts in the spring with the treatment mentioned above. That might save some $ in chemical, as Milestone is pretty spendy... Good luck. Be prepared to see a good flush of seedlings in 3-5 yrs... Christer October 29, 2014 Aryana Ferguson (Madrona Consulting) Hello all: Just to give you a heads up, broom seed can persist in the soil for up to 60 years so you may have to use spray for a long time -- same goes for pulling. There is some thoughts that fire/propane torch? will encourage the seed to sprout years earlier than it otherwise might so you might also look into treating the area with heat/flame of some sort as well as either pulling or spraying so that you can get the area truly cleared. Aryana Ferguson October 28, 2014 Bill Yake I have heard that some ruminants will graze down young broom can anyone verify? Also, shade seems to doom broom. So encouraging an over-story should provide long-term control. Bill October 28, 2014 Raj Prasad (Journal of Sustainable Forestry) Combating Scotch Broom 3

4 Yes, Bill, you seem right scotch broom does not flourish in shady under covers of mature Douglas-fir plantations, both shade and probably needle- fall restrict and stunt the growth but some broom plants can exist for a while in shade, probably with delayed growth and delayed flowering, setting of pods/ seeds?. Its interesting that scotch broom will affect (retard) he growth and photosynthesis of young seedlings of Doug-fir by about 20-25% in early stages of planting but once the conifer species establish, it will out grow the broom after yrs of planting. See Prasad R, 2000, Journal of Sustainable Forestry We are just finishing a manuscript--mapping of scotch broom in Vancuover Island with Landstat imagery - when published, I will send a copy. Kind regards, Raj Prasad Victoria, BC October 29, 2014 Elaine Stewart (Metro-Natural Areas Program) Many native forbs are growing in late fall and winter, though they can be hard to notice. I was on a site earlier this week and saw plenty of Micranthes, Achillea, and Ranunculus growing. The Delphinium comes up soon after the first of the year, along with camas and many others. Depending on the density of your broom infestation and the health of your native community, spraying can result in non-target damage. After years of trying everything from foliar sprays to weed wrenches, we ve landed on cutting larger plants (diameter greater than your thumb) and pulling smaller ones. Seems to work pretty well. We don t notice much, if any, resprouting on those bigger plants that we cut. A note of caution about triclopyr: we observed some camas damage after a winter treatment with triclopyr. Not sure why, since it s a broadleaf herbicide. But then, triclopyr will kill Iris pseudacorus, and it s a monocot too. Elaine October 29, 2014 John Kemp (ENC Corporation Environmental) I would totally agree with Elaine. Pulling SB when it is less than 18 inches tall is easy to pull out of the ground, especially after a moderate to heavy rainfall. Also cutting older units does work well if you cut it as close to the ground as possible and keep an eye out for seedlings next to the plant that was cut. Combating Scotch Broom 4

5 Jonathan Kemp, Principal EnCo Environmental Corporation P.O. Box 1212 Puyallup, WA Work: October 24, 2014 David Perasso I think it s always a question of the specific conditions. What other plants are there? how much broom is there? what resources are available? In a small remnant prairie in Covington that I m working with, there are multiple situations. In an area that is packed with natives there is a small amount of broom (2-4 plants per square meter) It would be crazy to use chemicals there. In another area there are thousands of small plants and the only natives are a few Rubus ursinus, which could easily be reestablished from propagules taken from the other areas. In this area, chemical control looks like the best way to go, at least for the first round of treatment. I agree that chemicals have their dangers and we should be cautious in their use, but in specific circumstances they can be the best solution. David October 29, 2014 Lynda Boyer (Heritage Seedings Inc.) Thank you Elaine, The damage of these chemicals to forb monocots seems to be in causing the flowering stems to bolt and get distorted. Garlon (triclopyr) may be even more damaging that 2-4D in this regard. Other affects I have seen from broadleaf herbicides on non-target groups in our seed production are: 1) Clopyralid in February causes Iris and Sisyrinchium not to set seed. 2) 2-4D kills Juncus species. 3) Triclopyr killed 1 year old Danthonia when spot sprayed to kill Rumex. Combating Scotch Broom 5

6 Broadcast use of these broadleaf chemicals in restoration areas is tricky. Sincerely, Lynda Boyer Native Plant Manager Heritage Seedlings Inc st Ave Salem, OR x 103 **Check out our new Website!!** October 29, 2014 Bill Yake Intensive goat grazing has been used to control brooms and gorse. Goats are most effective in controlling regrowth following initial control strategies. Goat grazing may be difficult if you are trying to reestablish natives during the control process since goats will also likely browse the native plants. Grazing broom plants gives poor control, unless animals graze it repeatedly throughout the growing season. Broom contains chemicals that limit the amount an animal can eat each day. Make sure to have other forage available for them to mix with broom for nutrition. Goats and sheep provide the best broom control. Goats confined to a small area can help control young shrubs or young re-growth from cut or burned shrubs. Scotch_Broom_CCP_4_19_12.pdf Grazing by goats during active growth of Scotch broom has been used successfully in New Zealand but requires several seasons for effective control. Native plant species are also at risk with this method since goats are non-selective grazers. Grazing by llamas has been used with some success at a few sites in California. No toxicity has been reported in goats or llamas. Sheep would not eat Scotch broom during a field trial in British Columbia. I believe cattle grazing on young plants has been successful on the Colvin Ranch (Rock Prairie, near Tenino WA). Bill October 29, 2014 Wendy Tyrell Combating Scotch Broom 6

7 May I add that most the methods discussed have proven to be somewhat to very effective in my experience - though I have only read on the effectiveness of chemical use, not applied it myself, due to our lands being under conservation covenant - no use of herbicides. However, the one factor that has not been mentioned in this conversation is community. It is my belief that the only real solution to broom control is community involvement. When people have a connection to the land and a commitment to continue removal and management over a long period of time, regardless of method - then success can be had. Without community - you have what I call "mow, blow and go restoration". There is just not enough funding or capacity to target one species successfully for such a long term management concern. Wendy October 29, 2014 David Sheperdson Ph.D. (Oregon Zooe) I am right with you on this Wendy, it s one of the roles that I hope zoos (with their huge audiences) can increasingly play in the future. David David Shepherdson Ph.D. Deputy Conservation Manager Oregon Zoo 4001 SW Canyon Road Portland, OR (office) (cell) October 30, 2014 Nathan Johnson (Center for Natural Lands Management) I just found this in the depths of the CPOP technical library: Not the latest thing off the press, but it illustrates some easily overlooked nuances. Combating Scotch Broom 7

8 Combatting Scotch Broom Appendix I Title: Winter Broom Treatment with Milestone Author: Nathan Johnson Affiliation: Center for Natural Lands Management Problem/Need: We want to know if it is possible to extend the window for chemical control of scot s broom into the winter when many desirable native forbs and grasses are not present on the landscape. Method: We applied 0.5% milestone VM with backpack sprayers onto the foliage and stems of broom plants within flagged area at JBLM Training Area 7S on January 23rd, Weather conditions were as follows: Temperature at application: 45F RH at application: 85% Wind: 5-6mph from the east Monitoring photos were taken on May 23, 2014, 4 months after the initial herbicide application. Plots were visually inspected several times prior to taking pictures on May 23rd. Pictures were again taken on October 24th, 9 months prior to treatment. Results: Figure 1 shows effective control of broom by winter milestone application 4 months after treatment. Treatment seems to have killed broom within 75-80% of the treated area. Earlier in the spring (March) observations detected minor differences between the treated area and the surrounding untreated broom. Some small chlorosis was seen, but no major damage to the plants. After the spring growing season it is clear that milestone effectively controlled scot s broom even when applied in cold-weather conditions. Patience is required to see the outcome Combating Scotch Broom 8

9 which wasn t apparent until well into the spring growing season. Further follow-up in October 2014 showed little-to-no re-sprouting confirming that the herbicide was translocated into the roots and completely killed the plant (Figure 2). Outlook: Chemical control provides longer control than mowing, and is much less labor intensive than hand-pulling. Winter spraying could be a good tool for areas where prescribed fire frequently does not kill broom. I hope to expand winter foliar application trials to include other herbicides (e.g. Garlon 4 ultra). Care should be taken to communicate areas which have been treated so that they are not mown or hand-pulled before the herbicide has had a chance to be effective. Combating Scotch Broom 9

10 Figure 1. Broom treated with 0.5% milestone in January 24, 2014 in the foreground. Untreated broom is evident flowering in the background. The author estimated 75-80% kill of the treated broom. Picture taken May 24, 2014, 4 months after treatment. Figure 2. Broom treated with 0.5% milestone in January 24, 2014 in the foreground. The author estimated 75-80% kill of the treated broom. There is little to no sprouting, indicating that the herbicide applied was translocated to the roots, killing the plant completely. Picture taken October 24, 2014, 9 months after treatment. Combating Scotch Broom 10