by Don Osmond
Don Osmund has worked at and enjoyed natural areas stewardship for 27 years (at MacArthur Woods in Lake County, IL and Military Ridge Prairie Heritage Area near Madison, WI). He wrote to ask a question about a post here. We responded in part with a question. Here is Don’s insightful response.
Prioritization
Considering the lack of resources & the magnitude of the task, I learned that prioritization is everything. Now I divide sites into parcels that are prioritized by potential for successful restoration. Within those parcels I prioritize the invasive species by the magnitude of its effect on native diversity as well as projecting how successful my efforts are likely to be for the number of years I intend to work there. If contractors are available, I avoid tasks that are more suitable for crews. This method ensures I’m focused on the overall goal of diversity enhancement, allows me to handle multiple species at any point in the growing season & avoids burnout by keeping goals realistic.
Considering the lack of resources & the magnitude of the task, I learned that prioritization is everything. Now I divide sites into parcels that are prioritized by potential for successful restoration. Within those parcels I prioritize the invasive species by the magnitude of its effect on native diversity as well as projecting how successful my efforts are likely to be for the number of years I intend to work there. If contractors are available, I avoid tasks that are more suitable for crews. This method ensures I’m focused on the overall goal of diversity enhancement, allows me to handle multiple species at any point in the growing season & avoids burnout by keeping goals realistic.
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| MacArthur Woods - Lake County Forest Preserves |
Attachment
I no longer get too personally attached to a site, task or the state of the natural world. Attachment created blinders that sometimes interfered with proper priorities. For example, I spent too much time on rare species until the ecologist gently & correctly encouraged me to focus on the entire habitat. It’s easy to get into a mindset that anything less than a pristine ecosystem is a failure. Initially I felt an urgency to fix the entire nature preserve before it’s too late, which led to viewing restoration as a war instead of a relationship. Which led to burnout. It may be more realistic to accept disturbance & change as natural, which implies we don’t need to burn ourselves out reshaping the world within a lifetime. We only need to shift the trajectory on a given piece of land towards more resilience against whatever the future brings.
Persistence
I no longer get too personally attached to a site, task or the state of the natural world. Attachment created blinders that sometimes interfered with proper priorities. For example, I spent too much time on rare species until the ecologist gently & correctly encouraged me to focus on the entire habitat. It’s easy to get into a mindset that anything less than a pristine ecosystem is a failure. Initially I felt an urgency to fix the entire nature preserve before it’s too late, which led to viewing restoration as a war instead of a relationship. Which led to burnout. It may be more realistic to accept disturbance & change as natural, which implies we don’t need to burn ourselves out reshaping the world within a lifetime. We only need to shift the trajectory on a given piece of land towards more resilience against whatever the future brings.
Persistence
I went to a lecture by Jack White & when asked how he was able to pull off the Illinois Natural Areas Inventory, he replied that persistence is the key. I applied that to invasives, telling myself if I’m more persistent than the weeds are, good things will happen.
The human aspect of restoration
Hiking in beautiful places is enjoyable, but since it’s mostly a sensory experience, it doesn’t provide the deeper satisfaction of restoration, which is primarily about relationship. Restoration shows us that nature isn’t always wonderfully harmonious & it isn’t always about survival of the fittest. There are times when self-centeredness is best for the individual & ecosystem, times when selflessness & cooperation are best & times for somewhere in between. Applying this to our lives, since we have the potential for self-awareness, it might be possible to know moment to moment where we are & where we should be on that selfish/selfless spectrum, so that we benefit ourselves & our community simultaneously.
Gear & techniques
I wasted a lot of time & abused my body using ineffective gear, so it would be great to have a moderated living document on the web for restoration gear, tools & clothing, with input from volunteers, contractors & managing agencies.
Physical training
To feel good at the end of a 7 hour day of brush cutting or weed pulling, perform daily abdominal exercises like sit-ups, boat poses & leg raises. It may take 6 months to feel the difference.
Invasive species time commitment
Reasonable suppression of most invasives takes at least 3 years of commitment (usually more) without missing a year. Some weeds will take >7 years.
Invasives like to socialize
One invasive often harbors or masks another so after controlling one weed, be prepared to control other weeds in the same location next season. For example, clearing a brush clone in a prairie can result in a Solidago or clover explosion the next year.
Creeping charley
At MacArthur, it displaces natives in northern flatwoods & is very hard to control.
Tall goldenrod (Solidago altissima)
Tall goldenrod (Solidago altissima)
I watched this invade from an old field into an 80-90% canopy woodland that had a weak forb/sedge layer and estimated 20-40% bare ground in the form of vegetation gaps. Solidago developed & expanded in this environment & after a few years of monitoring, it appeared to be permanent. It didn’t invade micro-habitats with decent sedge coverage. Since it was invading large areas & Lake County Forest Preserve District was planning canopy thinning, I used Transline & it worked very well as long as every stem was sprayed. Control was maintained 4 years after application. Transline is persistent & controls most composites so careful site evaluation is needed before use.
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| Tall goldenrod after spraying Left half - sprayed previous year Right half - just after spraying in September |
Garlic Mustard - initial approach
This was a real journey because in the 1990’s, MacArthur Woods was degraded enough to allow GM to spread throughout the preserve. My goal to control it in most of the 500 acres meant supplementing hand pulling with fall herbiciding of monocultures & spring herbiciding of small patches. The latter creates dead zones but they revegetated quickly so my thinking was as long as I could hit it every year, exhausting the seedbank was more important than temporary dead spots. By 2012 I was controlling 804 GPS waypoints every year but by that time, most had only a handful of plants & monocultures were eliminated.
After 7 consecutive years of mechanical & chemical control plus occasional burns, many of the 78 patches I monitored still had small numbers of 2nd year plants. This doesn’t necessarily mean >7 year seed viability since missed plants or pulling too early are alternative explanations, but studies show >10 year viability is likely.
Garlic Mustard - spring timing
For 3 years I monitored 60 locations during herbicide application in the 1st 10 days of May, then revisited a few weeks later to see what was missed. I omitted locations where missed plants due to human error were likely, such as in heavy vegetation or plants near a tree. Results: Locations with search areas >30’ diameter had more missed plants than smaller areas, confirming human error as a contributor. The most missed plants occurred in the year when I herbicided before they were in full bloom & the least missed plants was in the year when I sprayed a bit after full bloom. That observation included small patches where missed plants were unlikely, so I suspect not all plants had emerged when I sprayed before full bloom. I also noted at 10 revisited locations, there were 2nd year GM plants on the edge of the previously sprayed patch, raising the possibility that release from self-allelopathy caused rapid growth.
Garlic Mustard - new approach #1
Start scouting sunny areas on 4/20 (in northeastern Illinois) with the goal to start chemical control when most plants are in full bloom, but before siliques are present. Switch to shady areas when plants in those areas reach the same bloom stage. Control can begin earlier if there is enough time before seed drop to revisit those early patches. Scattered patches are prioritized over monocultures & waypoints with larger search areas are prioritized because blooming plants are easier to find. My data suggests this single visit method should result in 60-70% of small patches having 0 or 1 missed plants, assuming an experienced, focused worker.
Garlic Mustard - new research leads to new approach #2
Ecology Letters 24:327 (Residence Time Determines Invasiveness and Performance of Garlic Mustard (Alliaria petiolata) in North America by Blossey etal) has caused me to change strategy. It may be better to leave established monocultures alone, where the development of a natural biocontrol is more likely, and instead go after scattered smaller populations & ones that threaten high quality remnants. For moderate size patches, cutting at ground level or very targeted herbiciding is favored over hand pulling, because pulling disturbs potential soil biocontrols & creates optimum conditions for further invasion. For sites with good competition, it may be better to not control GM at all. For sites where it’s unlikely that decent competition will occur, perhaps reassess the desire for GM control by considering ecosystem quality & if resources are better used for other tasks or on another site. I view GM control as a temporary measure to buy time until robust native competition (or potentially a natural biocontrol) is established.
After 7 consecutive years of mechanical & chemical control plus occasional burns, many of the 78 patches I monitored still had small numbers of 2nd year plants. This doesn’t necessarily mean >7 year seed viability since missed plants or pulling too early are alternative explanations, but studies show >10 year viability is likely.
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| Ground layer condition where garlic mustard persists |
Garlic Mustard - spring timing
For 3 years I monitored 60 locations during herbicide application in the 1st 10 days of May, then revisited a few weeks later to see what was missed. I omitted locations where missed plants due to human error were likely, such as in heavy vegetation or plants near a tree. Results: Locations with search areas >30’ diameter had more missed plants than smaller areas, confirming human error as a contributor. The most missed plants occurred in the year when I herbicided before they were in full bloom & the least missed plants was in the year when I sprayed a bit after full bloom. That observation included small patches where missed plants were unlikely, so I suspect not all plants had emerged when I sprayed before full bloom. I also noted at 10 revisited locations, there were 2nd year GM plants on the edge of the previously sprayed patch, raising the possibility that release from self-allelopathy caused rapid growth.
Garlic Mustard - new approach #1
Start scouting sunny areas on 4/20 (in northeastern Illinois) with the goal to start chemical control when most plants are in full bloom, but before siliques are present. Switch to shady areas when plants in those areas reach the same bloom stage. Control can begin earlier if there is enough time before seed drop to revisit those early patches. Scattered patches are prioritized over monocultures & waypoints with larger search areas are prioritized because blooming plants are easier to find. My data suggests this single visit method should result in 60-70% of small patches having 0 or 1 missed plants, assuming an experienced, focused worker.
Garlic Mustard - new research leads to new approach #2
Ecology Letters 24:327 (Residence Time Determines Invasiveness and Performance of Garlic Mustard (Alliaria petiolata) in North America by Blossey etal) has caused me to change strategy. It may be better to leave established monocultures alone, where the development of a natural biocontrol is more likely, and instead go after scattered smaller populations & ones that threaten high quality remnants. For moderate size patches, cutting at ground level or very targeted herbiciding is favored over hand pulling, because pulling disturbs potential soil biocontrols & creates optimum conditions for further invasion. For sites with good competition, it may be better to not control GM at all. For sites where it’s unlikely that decent competition will occur, perhaps reassess the desire for GM control by considering ecosystem quality & if resources are better used for other tasks or on another site. I view GM control as a temporary measure to buy time until robust native competition (or potentially a natural biocontrol) is established.
I took pans of boiling water and poured them over creeping Charlie in a native plant garden. This killed the creeping Charlie. Seed was then sown in the area. Golden Alexanders and woodland grasses filled in the area where the creeping Charlie had been killed. Possibly, instead of herbicide, heat from a Weed Dragon Torch would be enough to kill the creeping Charlie without killing other fire adapted native plants.
ReplyDeleteI have overexerted myself. When I was working for eight hours a day performing strenuous restoration work, I would get dangerous rhabdomyolysis. I had to learn my limits. For example, if I am applying basal bark herbicide with a mini-paint roller, I limit myself to six hours a day. If I am using a dandelion weeder to remove red clover, I might work 2 to 3 hours and then do another activity using different muscle groups. Often, it would take me three days to recover fully from a long and strenuous workday. I had to plan my schedule accordingly.
Individuals that accept the value of enhancing native vegetation and DO somethng to toward that value almost always (>99%) make the community more natural than doing nothing. All such should be honored. Effieciency is desirable but technique success varies among applicators and sites. It is good to hear what has worked and not worked by particular individuals at particuler sites, but one needs to learn what works for oneself and the site one is taking care off. One learns by observing and inference.
ReplyDeleteExcellent point about site variables affecting results. I’m always trying to figure out if a given study or advice from a practitioner applies to the site I’m working on. The GM study I referenced was compelling because it sampled many sites over a wide geographic area.
ReplyDeleteRegarding motivation to do good versus doing good, I’ve seen some activities that harm more than help. The site variability you mentioned is part of it. Also lack of an organization that reviews the data & issues quality standards for strategies that are widely applicable. For example, after reading a study on herbicide exudation from roots, I contacted some experts & while they saw no widespread problems with Garlon 4 applied in the dormant season, they sometimes observed small dead zones around each stem that become a problem when treating dense brush clones. That caused me to switch to glyphosate on those clones. That advice applies to any site & should be widely disseminated to restoration folks. Another contributor towards doing harm is the lack of proper monitoring to determine if a given intervention is helping or hurting. I have zero time to do such monitoring (which I regret) & I suspect that is true for most of us. Nowadays I weigh the potential harm of my activities (trampling, off-target herbicide kill, disruption of nesting birds, etc) against the potential benefits.
I have been trying to fill the void of a lack of monitoring and quality control in restoration. I have published my observations on the work that is happening at various sites on the following blog. Soon I will be able to report initial results, like effectiveness of herbicide applications and damage to adjacent vegetation.
Deletehttps://stewardshipchronicles.blog/
If you would like me to visit and write about a specific effort at MacArthur Woods then contact me. Stephen Packard has my contact information and can forward it to you. You should be aware that my blog posts will be based on observations and not with a purpose of giving praise merely to support stewards’ vanities.
I have kept track of my applications of triclopyr ester in basal oil (20 percent V/V or 12.3 percent active ingredient) to the minimum amount of stem length I have found to give good control (95 percent plus). For a typical, uncut or unburned, buckthorn or Asian bush honeysuckle in the Chicago Area this is a length of stem equal to approximately twice the diameter at ground level. For buckthorn or Asian bush honeysuckle with stem diameters less than two inches at ground level, I increased the ratio of stem length covered to three then four times the diameter at ground level as the stems get smaller. I applied triclopyr ester in basal oil only during the dormant season (November to March) to minimize damage to adjacent vegetation from vapors. I applied the herbicide with a mini-paint roller, waiting for it to stop dripping in a bucket, so little to no herbicide was dripped onto the ground. I stopped my application about an inch above ground level.
The following season, I returned and observed the “ring-of-death” around the treated buckthorns and Asian bush honeysuckles. My results from applying this herbicide in 2021/2022 was that the ring-of-death was less if the application was done at least three days before rain occurred. No ring-of-death was visible if the application occurred a full week before rain occurred. My observations from the 2022/2023 season match observations from the 2021/2022 season.
The triclopyr ester that is not absorbed into the plant volatilizes. As more time passes, then rain washes a diminishing amount of herbicide into the soil. You don’t need to observe the ‘ring-of-death’ to know the herbicide is dissipating. The smell of the herbicide in an area becomes less intense as days pass.
I have forwarded my unpublished study results on the cause of the ring-of-death to various conservation organizations including the Lake County Forest Preserve Ecologists. It appears this information has not yet been passed down to stewards.
As for glyphosate, this too can cause damage to adjacent woody species through root connections. This is well known. I have unintentionally killed a prairie crab apple applying glyphosate to a buckthorn within a foot of the prairie crabapple’s trunk. I thought the prairie crab apple might live, but after a few years the damage from herbicide finally killed it. I have also observed damage to foliage of untreated buckthorn up to several feet from treated buckthorn stems that had herbicide applied to a frill. I use frilling because I have found it to be more effective than cut stump treatment while saving time on rework. Frilling is especially effective on clonal species, killing stems after the first treatment instead of needing repeated cutting and herbicide application to these cuts. I have reduced the concentration I apply when frilling to ~25 percent active ingredient. This still kills most buckthorn outright. I have observed that some larger buckthorn will send out a small amount of epicormic shoots along the trunk for a few years. Until I can narrow the ideal concentration down further, ~25 percent active ingredient glyphosate has proved to be a good balance between effectiveness and minimizing off-target damage.
I’d like to make a correction that my previous comments applied to ineffective activities as well as ones that did harm. A strong majority of stewardship & natural resource agency actions are beneficial but there is always room to learn & improve.
DeleteI moved out of state so I haven’t been at MacArthur since 2013.
Very interesting results for basal bark & going forward I’ll pay closer attention to post application precip, even though I’m doing cut stump treatment, which should be better since less herbicide is used. I see “The Tallgrass Restoration Handbook” recommends 1-4 days precip free post-app for Garlon.
I wonder if the issue involves exceeding the maximum use rate on the Garlon 4 label of 8 quarts/acre/year (not grazed or cropped). Check me on my math but if I use a 30’ x 30’ brush clone as an example (0.021 acres), the max amount of Garlon 4 permitted is 0.165 quarts. At a 20% concentration, that is 0.82 quarts of spray. But we don’t know what amount of off-target kill was tolerated when the manufacturer calculated the max use rate.
My sources have no reports of glyphosate off-target kill so it would be good to know how widespread that is.
A lot of this depends on site conditions. Brush is an existential threat to prairies, so in many cases, especially with scattered brush or where seeding will occur, a small amount of off-target is acceptable as long as it doesn’t involve rare plants.
My observation is about the same amount of triclopyr ester in basal oil needs to be applied to typical (uncut and unburned) woody invasive species (> 2 in diameter at ground level) whether the application is to a cut stump or the basal bark, unless the woody invasive species stem is large (> about 8 inches at ground level) with thick furrowing bark. For larger individuals, I have found that I can apply the herbicide higher up on the trunk, where the bark is thinner, and still get excellent control with the previously mentioned application rate covering about a length of stem equal to twice the diameter of the woody invasive species at ground level.
DeleteI have seen a lot of cut stump applications where a mini-paint roller was rolled across only the cut surface and the woody invasive species sprouted the next growing season. This type of work does not cause harm, but it does create a lot of rework treating the multi-stemmed sprouts until the target plants receive enough herbicide that they are finally killed.
During a six-hour day of applying triclopyr ester in basal oil with a mini-paint roller, I usually apply about two quarts. This a lot less than the people who use backpack sprayers. With a mini-paint roller, I get all but a few drops of herbicide on the target plants. This compares to backpack spraying that has overspray and dripping on the ground. Still, it is possible to exceed the maximum use rate where stems are very dense. I must be aware of this limit.
The above being said, I do not think the ‘ring-of-death’ issue is related to the maximum use rate. This is because the ring of death issue is mostly a concern in areas where the buckthorn is still small and spread out. These are the areas that have natural area quality that deserves a careful application limiting off-target damage. Where there is a thicket that has become a near buckthorn monoculture typically there is little to no vegetation to observe off-target herbicide damage.
I quickly wrote a blog post with an image of common buckthorn that has off-target damage impacts from the application of glyphosate to a frill (cuts around the stem). Shown is the only image I was able to quickly locate showing off-target impacts from treating a woody stem. Although, I have lots of images of off-target impacts from several types of foliar treatments.
https://stewardshipchronicles.blog/2023/05/15/off-target-damage-from-applying-glyphosate-to-frills-cuts-around-stems/
I think most stewards have observed what happens when herbicide kills high-quality plants. What fills the area is not high-quality plants. For me, it is often crownvetch, field thistle, bittersweet nightshade, creeping Charlie, and if I am lucky biennial evening primrose. Controlling the invasive species without killing the plants we are trying to save is not only good technique, but it also saves time. Trying to get quality plants to recover in areas damaged by herbicide is a prolonged battle.
I use a canister type sprayer with a cylindrical nozzle that projects a narrow stream. With low pressure, a trigger stop & a light hand I can seep just enough herbicide onto the cut stump with little overspray. In 6 hours I use 1.2 quarts when treating mostly small diameter brush like dogwood. The spray wand goes into a drip catcher on the outside of my carry bucket when not spraying.
DeleteI spent many years cutting gray dogwood stems, watching people paint herbicide on the stumps, and seeing the dogwood clones sprout more densely the next year. The Forest Preserves of Cook County hired a new burn boss. The fires he got on the ground did more to control the gray dogwood than I could do cutting it with loppers in a lifetime.
DeleteWhen controlling grey dogwood, I suggest you try applying 25 percent active ingredient glyphosate to frills (cuts around the stem). I have found that this method will control gray dogwood and staghorn sumac after the first application without causing damage to adjacent vegetation. It takes more time initially, but it works after the first application which saves time compared to repeatedly cutting and treating.
I wrote a treatise on applying herbicide to frills on common buckthorn. After thirteen drafts, it was not finished but I decided I had worked on it long enough and Mr. Kleinman published it on his blog. Like most publications, I have learned a few more things since it was put on Mr. Kleiman’s blog. The treatise is on treating common buckthorn, but the technique is the same for gray dogwood or staghorn sumac.
https://grasslandrestorationnetwork.org/2018/02/18/cut-stem-treatment-on-buckthorn/
I can’t use basal bark or frill at the site I work at because treated clones are often infested with tall goldenrod or white sweet clover in the years after. With limited resources, I need to efficiently wack goldenrod just before bloom & pulling clover is much easier & safer (eye injury while stooping) with no dead brush around.
DeleteThe sources I checked report varied results with dogwood so this is one of those situations where more research is needed & also, as JWPboss said, experimentation at each site. There is a ton of possible variables including clone health & size (due to age, stress from controlled burns, etc), cut stump delay time between the cut & herbicide application, application method consistency, precip soon after application, season (dogwood pushes sap mid April), type of oil used, spray versus sponge or roller, water hardness with glyphosate.
Until last fall/winter I applied cut stump treatment to dogwood with 50% Roundup or equivalent in soft water, cutting low to the ground, applying herbicide immediately after the cut, no precip within 8 hours, no snow on the ground, treating every stem, mostly late fall or early spring. The clones I checked the following summer were all dead. I was afraid of nailing native remnant grasses with glyphosate since they were sometimes green near the soil in late fall so I switched to 20% Garlon 4 in bark oil. But going forward I’ll use a hybrid approach: glyphosate on dense clones to minimize potential dead zones merging together & Garlon 4 on scattered brush in remnants (with no precip a few days after) to minimize potential off target grass kill. Also use glyphosate if grasses are clearly dormant. Hopefully I can snap some pictures this summer so I can document if this method works to minimize native forb kill.
Controlled burning only sets brush back & I’m interested in getting rid of it in & near remnants. For large areas with more degraded vegetation that will be seeded and/or foliar sprayed, it makes more sense.
I can understand not wanting to get poked in the eye. I go into dense uncut buckthorn thickets to apply herbicide to frills or directly to the bark. Even with wrap around glasses, I’ve gotten poked in the eye. I wear safety glasses over my prescription glasses which leaves a gap. Sharp twigs will eventually find this gap. I should wear a face mask in these thickets.
DeleteI do not worry about the gray dogwood clones that I frill once they are dead. After a few years, I just knock them all down in the same direction with my foot when I am doing follow up on buckthorn saplings. The larger staghorn sumac stems create a mess when they all fall over. I have been stepping from stem to stem above these piles reaching down with my long-handled mini-paint roller to treat common buckthorn. These dead sumac stem piles are full of tall goldenrod. I have not been worrying about it. I will just let these piles decompose, see if prairie species spread into them from adjacent areas over time, and work on other priorities. In the meantime, the wildlife loves the loosely packed fallen over staghorn sumac stems as cover.
The dose is important. Technique is important too. You must be getting much more herbicide on the gray dogwood stems than people daubing them with a paint brush.
I do the opposite of the ‘hybrid approach’ you mention. I use the triclopyr ester in basal oil in low quality areas (usually near complete monocultures of common buckthorn), where damaging off-target vegetation is not much of a concern. The exception is if rain is not forecast for at least a week. In this case, I will use triclopyr ester in basal oil in high-quality areas. Otherwise, in high-quality areas I apply glyphosate to frills. At the concentration I am using, about 25 percent active ingredient, I am not seeing any damage to non-target vegetation. When applied carefully there is no ‘ring-of-death,’ as will happen if triclopyr ester in basal oil is applied too soon before rain. Your results applying to cut stumps are probably similar. I have found I can apply glyphosate to frills right before rain occurs (minimum of 20 minutes recommended) and it is still effective without causing off-target damage.
In remnants, I would use glyphosate applied to frills because it works for me. Applying glyphosate to cut stumps is working for you, so I expect you would keep doing it.
In my previous comment when I said, “The Forest Preserves of Cook County hired a new burn boss. The fires he got on the ground did more to control the gray dogwood than I could do cutting it with loppers in a lifetime.” These observations were not in a remnant prairie, they were in a prairie reconstruction on previous agricultural fields. The abundant warm season grasses super charged by previous fertilization burned extremely hot. This is likely the reason many of the gray dogwood clones were eliminated by repeated burning. The Poplar Creek Prairie Stewards like to show pictures of when they started. The old field vegetation was full of gray dogwood clones. I helped gnaw away at many one stem at a time. Following repeated hot burns there are still dogwood clones in spots (especially east facing slopes) but fire got rid of the gray dogwood where it burned hot.
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DeleteI know the Garlon 4 label says not to apply it when snow is present. However, I have tried this using my no-drip technique with a mini-paint roller. I applied the herbicide to the part of the stems above the snow. The next season I did not see a “ring-of-death.” When snow occurred within a few days after applications, I have not observed a “ring-of-death” if the temperature is cold enough that the snow never becomes ‘wet.’ Since the risk of rain is nearly eliminated during cold periods, winter can be the best time to apply triclopyr ester in basal oil without the risk of damaging adjacent vegetation. It is unfortunate that this is not allowed by the label. I might have to write Dow Chemical and see if I can get the label changed.
DeleteI have also applied glyphosate to frills on stems above snow. I can do this if the bark is not frozen. This is when the ambient temperature is about ~28 degrees F, or above, on a sunny day. I have not observed off target impacts after applying about 25 percent active ingredient glyphosate to frills with a paint brush whether or not snow is present. If you drip glyphosate onto cut stumps so it does not run down the stump, I think you should be able to apply glyphosate to stumps above snow without impacting adjacent vegetation.
My previous mentioned observation that it takes about the same amount of triclopyr ester to control invasive woody species whether it is applied to a cut stump or the basal bark is not true. Additional observations I made this summer from several sites has now convinced me.
DeleteWhen I do basal bark applications again this season, I will increase the amount of stem cover above a length of two times the diameter of the stems for two-to-eight inch common buckthorn and above a length of four times the diameter of the stems for common buckthorn less than an inch in diameter. My application from last season failed to kill the female common buckthorns.
I visited the Poplar Creek prairie restoration a few times this summer. I found a lot of little grey dogwood sprouts in the restoration area. There are areas where there used to be grey dogwood clones but now none are present. This could have been from the stewards cutting and applying herbicide. I remember prescribed fire killing the dogwood clones from the edges when fires again started being conducted. I do not remember the top killed parts of the clones having sprouts from the ground. I still think fire can kill dogwood clones. However, looking at where I see dogwood clones across the topographical gradient, I don't see convincing evidence that fire intensity is necessarily the reason.
ReplyDelete