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Friday, September 22, 2023

Escaping From Too Much Tall Grass

Some people think they're in a "restored prairie" when they stand among head-high big bluestem, Indiangrass, and little else. But true prairies are complex and relatively compact mixes of mostly rarer grasses and wildflowers, the grasses and most vegetation waist-high or lower. The common grasses in a high-quality prairie are little known to most people: prairie dropseed, Leiberg's panic grass, and porcupine grass. The dense tall grass stands are almost a delusion. 

Dan Carter does a fine and important job (click here) summarizing the grass issues in a technical post.

He also does a good job of citing the literature, though most of it is little accessible to most interested people. In fact, much of the most significant conservation writing these days is not in journals; it comes from busy, dedicated people like Dan. 

A real prairie in early summer looks like this:

And in mid summer, it looks like this: 

Yes, the tall grasses will emerge here and there in August, but they'll be shorter and scattered, compared to a planted tall grass stand.

I looked in vain for a late August photo of the very high quality area at Somme Prairie, the one I know best. Somehow, this is all I found:

The only grass I can identify here easily is dropseed. I'll look for more photos and add them when I can. In high competition, many plants don't bloom every year. It's long been impressive to me that we rarely see even a single stem of big bluestem in the Somme high-quality area. In some years, there's lots of porcupine grass early and then much little bluestem mixed with the dropseed. In some years there'll be a lone stem of Indiangrass in every square yard or so - typically about four feet high, not six or seven. 

So, today, September 24, I took more photos. A typical one is below. It's not all that great a photo, but it does show how tall the grasses are:

There's little grass that's more than knee-high, in this mesic prairie, this dry year. 

In the above photo, starting at the top, there's a strip of sky, a strip of trees, and then a narrow strip of a tan color. That strip is Big Bluestem and Indiangrass, in a restored area, well away from the high-quality remnant. Many of the poorer-quality areas of the Somme preserves have vast stands of those head-high tall grasses. But, as Dan Carter makes clear, these stands of tall grass are not the goal of conservation and not true (or high-quality) tallgrass prairie. 

Thursday, September 7, 2023

Biodiversity Discoveries in the Dunes

Discoveries like: a baby endangered turtle, Pitcher’s thistles, the meaning of life, and other revelations. 

We are adventurers. We work, celebrate victories, and make obscure discoveries. 

There's the rare baby endangered Blanding’s turtle (below) … happily sighted while a dozen of us were pulling malignant sweet clover. We picked it up and moved it away from trampling feet. Adult Blanding’s turtles may be rare, but babies are Super-Rare. On most sites, eggs and hatchlings are eaten by over-abundant meso-predators – raccoons and opossums. 


Thus, this toddler is a mini-miracle. Its success can be credited to this prairie’s health, diversity, and size. Coyotes patrol it. We hear them howl and harmonize. Because raccoons and opossums know what’s good for them, they tend to stay closer to edges and trees. Most high-quality prairie remnants today are less than five acres in size. This one ranges from a mile to half-a-mile wide and eight miles north to south. Here baby Blandings have a chance here. 


Blanding’s turtles live up to 80 years. They mature enough to breed only after reaching 14 to 20 years old. According to Lake County Forest Preserves, this now rare species was once common and known from 17 places in Lake County. Most are gone. The only currently viable habitat is the eight-mile Chiwaukee-Spring Bluff-Hosah-Illinois Beach complex. That’s the miracle where we work. For this turtle, like nearly all threatened biodiversity, the main threat is loss of healthy habitat. 

(Important note: it's illegal to handle or move Endangered species without authorization. They are vulnerable to diseases that people can spread. Moving this one, so it wouldn't get stepped on, made sense. But generally, it's best and important to leave them alone.) 

Pulling invasive sweet clover from sand prairie.


Intensive Care for Pitcher’s Thistle

We found the rare beauty below while GPS-ing populations of crown vetch – a malignant plant that can wipe out acres of habitat. We’ve eliminated it from large areas of this preserve and plan to get to the rest.

This Endangered, yellow-flowered thistle was a surprise – near an advancing patch of the dangerous vetch. Once common around the Great Lakes, the dune habitat of Pitcher’s thistle is largely gone. The Chicago Botanic Garden, U.S. Fish & Wildlife Service, and others launched a recovery plan for this thistle in 1991. When we reported our find to the Garden, we were told that they were “surprised and delighted” to know it was still here. They hadn’t had reports of it here for a decade. 


We found two plants in one area and seven in another. This blog will give only vague locations for endangered species. None were blooming during this drought year. This species is a “monocarpic perennial” – it lives for a few years without blooming, all the while increasing the resources stored in its roots. Then, when it finally feels bullish enough, it blooms, sets seed, and dies.  


Studies show that alien beetles then eat from 10% to 90% of the seeds of unprotected plants. Goldfinches may eat the rest. But, if we give it extra care for a few years, protecting and spreading seeds in good potential habitat, we can sometimes build up populations robust enough to then make it on their own. We’ve done that with other populations of endangered species. We hope to do it next for Pitcher’s thistle.


Good News. Bad News. Good News.

In August as we battled crown vetch and clovers, we regularly saw this pair of sandhill cranes. As a breeding species, it was extinct in Illinois for decades. A dramatic recent conservation success has been their resurgence. 

But two cranes poking around wetlands and savannas in August means that this year’s colts didn’t make it. Cranes nest on the ground. Hatchlings look for food as they follow their parents, walking. As they get bigger, coyotes want to eat them. The parents are tough customers and fight off the coyotes, at least most of the time. Cranes live for twenty years, so they don’t have to reproduce successfully each year. This year, this pair failed.


But later, working along Dead River, we looked across to see the family seen below. Parents and at least one colt survived in this off-limits-to-most-people sanctuary. Bless them.  

The Long View

Illinois Beach isn’t mostly beach; it’s better called a “dunesland.” Parallel to each other, up to twenty long, low, parallel sand dunes stretch back a mile from Lake Michigan. They’re ancient, now vegetated and stable, created as Glacial Lake Chicago retreated ten millennia ago. Those parallel dunes once also covered much of the city of Chicago, where of course, they’re now mostly bulldozed, though some survive (minus their biodiversity, except for some old oak trees) in Chicago city parks. 

How bad are cities? Consider this fact: Visionaries from Chicago, Champaign, and Rockford did the major work of discovering the concept of the ecosystem, inventing biodiversity conservation, and establishing a world-model nature preserve. Illinois Beach Nature Preserve is a key jewel. Cities did it. Agriculture is good, but it didn’t. And after years of seeming safe and protected, more recently the growing Nature Preserve System has suffered fearsome degradation from invasive species, lack of fire, and diminished resources


Vigorous empowered volunteer communities have made life-and-death differences to many preserves. Stewards and constituency are needed. As we restore habitat and make discoveries, we also discover how human communities grow and change the world. Not everyone can do everything. 

The general public is not allowed in the square-mile expanse of prairie and black oak savanna south of the Dead River. We stewards are allowed because we’ve been trained and authorized … because we work for the preserve’s benefit. Trained? Let’s make that clear: You’re invited to come and learn and work. We train you on the spot. And next time, you may train somebody else. We authorize you to pull sweet clover after being trained for just that. It’s not hard to learn. Next time we may gather and disperse the seed of an endangered species “that don’t get around much anymore.” Some of us are trained to use chainsaws or apply herbicide sensitively. In time we all learn a lot from each other.


While doing the good of pulling sweet clover, we may meditate, discover, or have conversations. A thriving community is both varied and unified, in a comfortable way.


Sweet clover, too, dies after it makes seeds. The point of pulling sweet clover is to get rid of those baleful seeds. Here Harrison collects armloads of them and hauls them to a habitat where they won’t grow. Just rot. Serves them right. 

In the process we experience. We find endangered species and such treasures that perhaps others wouldn’t notice. Our perceptions are expanded and multiplied by so many good minds. Turtles have belly buttons? Who knew? New volunteer Regina taught us on her first day. Thanks, Regina. 


For more about Blanding's turtle threats and recovery efforts, click here

From the sublime (little turtle) to the ridiculous (cinder blocks in the dunes?): In the landscape below, you see sand prairie on the dunes in the foreground, and behind are oak savanna and a glimpse of Dead River.

But look closer, and in the dune blowout you see cinder blocks. Really? They’re not doing much harm, but should they be in this hallowed place?

We lugged them out to the main trail, and the staff came with a vehicle to haul them to oblivion, which they deserve. Bit by bit, better and better. 

We invite you (or perhaps someone you know?) to help expand and help lead this fledgling group of new biodiversity conservation stewards. 

Please spread this post and the flyer below.  
Following that kick-off, the new group is now organizing stewardship work initiatives every Saturday at 9 am. Meet at the Illinois Beach nature center parking lot. 


Thanks to Jo Sabath for taking those Blanding's turtle photos and to Jo, Eriko Kojima, and Amy Doll for edits to this post. 

Thursday, August 24, 2023

Bringing your A game to herbiciding

By Don Osmond

Don is a long-time expert volunteer steward. He invites suggested edits and feedback generally.

Veteran practitioners will be tempted to skip this article, but I tried to include items of interest for all skill levels using a wide variety of high quality sources plus my own experience.

If I could suggest only one thing to herbicide applicators, what would it be?

Get the herbicide operator/applicator study guide for your state & read it cover to cover.  It’s easy to forget stuff or develop bad habits & hitting that guide every few years for my license renewal was an excellent way to get back on track.


How to decide if herbicides are needed

An invasive species management plan is essential.  It sets priorities for each invasive & land parcel based on available resources for the number of years required to suppress the invasive to the desired level.  It forces you to think about the entire ecosystem, the life cycle/seed longevity of each invasive & whether herbicide use makes sense.  At the steward level, you don’t need the rigor of an ecologist generated site restoration plan.  It’s fun to watch the plan evolve as you learn new things & it serves as a blueprint for your successor, so all your hard won knowledge isn’t lost.  There are many other benefits to a plan, such as nailing down the dates when mechanical control should start for each invasive & at what date to switch from one invasive to another.


Explaining to visitors (and reminding yourself) why herbicides are necessary

Most of us would probably not use herbicides if each nature preserve had an army of young, physically fit volunteers or contractors who were available over 4-12 consecutive years at the right time period to cut, pull or dig every weed.  Since that will never be the case, most of us will need to herbicide.  The exceptions are sites that are very small, have good native competition with few weeds or where the management goal is not related to preserving or increasing the percentage of conservative plant species.  The following are some reasons to use herbicides:

  • In the 1960’s, Rachel Carson correctly shifted public opinion away from the view that large scale use of pesticides have no risks.  But concluding that all pesticide use is bad would be an overcorrection.  A balanced approach is usually the best & that means using the proper techniques to apply low toxicity herbicides targeted at specific plants or patches.
  • Mechanical control of weeds without herbiciding can overload the restorationist for several reasons.  It must occur in a limited window of time.  The plants usually must be in bloom to ensure finding most of them, but if you wait too long, seeds are set.  Plus some weeds like wild parsnip & sweet clover have a proportion of plants with delayed emergence, requiring multiple passes separated in time, taking time away from controlling other invasives.  Weeds can have occasional bumper crop years due to the plant’s life cycle, controlled burning, brush clearing, etc.  Also, some years can be too hot or wet to finish mechanical control before seed drop.  Seed drop must be avoided at all costs if native competition is weak or the soil microbial diversity is low, because it can set you back years, depending on seed longevity.
  • I used to think about each invasive plant in isolation, but now I see that all the efforts during a given growing season are related to each other.  For example, if I herbicide wild parsnip in the fall & spring, that reduces the time needed to mechanically control it in summer, which in turn allows me to get white sweet clover at peak bloom when it is easily found, which in turn lengthens the knapweed window, giving me time to dig or pull the root out instead of the less effective but quicker method of wacking.  So herbiciding just one invasive increases your effectiveness for multiple invasives, making it more likely you can increase your weed control area over time.
  • Herbicides are essential for woody plant control.
  • Some other advantages of herbicides are the ability to get multiple generations simultaneously for biennials, less physical toll on the body compared to mechanical control, better control for invasives that reflower compared to cutting or mowing & less disturbance of soil for invasives that must be pulled or dug (soil disturbance=more weeds).


Keep-out areas

I don’t recommend herbiciding in high quality remnants, with the exception of careful application to crown vetch.  In addition to the possibility of off-target kill, we don’t know enough about herbicide effects on the soil microbiome.  If you think herbiciding in a remnant is necessary, consult with an expert first.


In addition, I avoid shores, riverbanks, areas known to flood if heavy rain is forecast a few days after spraying & well traveled footpaths.


How do I know if herbicides are working?

Seeing the leaves curl & turn color may not be enough.  You want to be sure the root was killed & not just the top.  When trying a new herbicide/adjuvant or concentration, flag a spray plot & a nearby non-sprayed control plot with the same density of weeds, competition level & habitat type in each.  It’s helpful to have 3 spray plots with concentrations a bit above & below your target to see if you are on the edge of effective control.  Monitor a year later to verify density reduction compared to the control plot.  Again, the climate should have been somewhat average during the previous year.  Make sure no controlled burns occur in the year after application because that may affect results.  Also, don’t experiment if the weather before spray time has been abnormally wet or dry.  Relying on the experience of others can provide a starting point for herbicide use, but there are enough variables involved to warrant doing your own experiment before spending a lot of time & money.


Treatment failures

If a treatment fails, you may not know about it for months since root death won’t be evident until the next growing season.  That could mean a lot of work down the drain, so it’s important to get it right the first time.  Good detective work is needed to find the root cause of failures, so it’s best to investigate your entire process for the following:

  • Errors in calculating concentrations, sprayer calibration or mixing.
  • Rain too soon after application or applying with too much dew on the leaves.
  • Not getting enough herbicide on the plant, especially true for painting, rolling or wick/sponge application.
  • If multiple people have access to herbicide: somebody created a custom mix or transferred herbicide & forgot to relabel the jug.
  • Spraying foliage when the plant isn’t actively growing or is under drought stress.  Also, some plants are most vulnerable during the stage when they are pushing resources into the roots.
  • Using hard water with glyphosate without a water conditioning additive like ammonium sulfate.  One study found a 60% decrease in toxicity when used with water at 50 ppm hardness.
  • A mix that is above or below the label recommendation for concentration or rate.  If you experiment with a lower rate, failures can occur even if your experiment was successful.  The lower rate may work for a given competition level, stage of growth, age of plant, drought severity, etc but if those variables change, that rate may no longer work.  Recommended rates create a margin that reduce the effect of variables.  If you try a rate higher than recommended, it may kill the leaf too quickly, interrupting translocation to the root.
  • Not using an adjuvant such as methylated seed oil.
  • Spraying rosettes too early, resulting in many new plants emerging after spray application, making you think the application failed.
  • Inconsistent spray method for a given applicator or inconsistency due to having multiple applicators.  Also poorly trained applicators.
  • For clonal plants: not treating every stem or treating only part of the clone & then waiting too long to finish the rest of it.  Note that clones (especially older ones) can require several years of repeat treatment, 
  • For woody plants
    • Waiting too long between cutting/frilling & herbicide application
    • For basal bark: band of herbicide too narrow or not herbiciding the entire circumference
    • Not cutting stems close to the ground
    • Not cutting horizontally (herbicide runs off the cut stump)
    • For some plants like dogwood, herbiciding when the plant is pushing sap upward in the spring.


Off-target kill

Spraying invasives when native plants are green will be a judgement call based on what is best for the entire ecosystem in the long term.  Sacrificing a small number of common native plants is usually acceptable if the invasive plant being sprayed is known to displace natives, the invasion is beyond what mechanical control can handle & your management plan designates the area as high priority.


Practice proper technique regarding wind speed limits, nozzle height above ground & nozzle type (avoid those with droplet size rated as “fine”).  Decide if the weed can be effectively controlled in the rosette stage when most natives are dormant.


Wind causes spray drift, but with the low pressure sprayers we typically use, it is often not a big deal.  Plus the wind at ground level is much less than at your head.  I’ve sprayed in degraded areas with no problems up to 15 mph average as long as gusts are below 20 mph.  For spraying where many natives are present, spraying near property lines or for foliar brush spraying, winds should be below 7 mph or so.


Exceeding the maximum use rate on the label may result in off-target kill or unintended environmental effects.  This rate is listed in a different place than the spray rates for particular weeds.  For example, the Garlon 4 label states a max use rate of 8 quarts per acre per year for cut stump/basal bark.  Lets say you want to basal bark a 30’ x 30’ brush clone.  Convert to acres: (30 * 30) square feet/43560 square feet per acre = 0.021 acres.  8 quarts per acre * 0.021 acres = 0.168 quarts or 0.158 liters is the maximum amount of Garlon 4 you can use.  If you mix Garlon 4 at 20% in bark oil, that means 0.158 liters/20% = 0.79 liters or 27 ounces of spray solution in your tank or bottle is the max you can use on that clone in a year.  I use about 1.2 liters in 6 hours of cut stump treatment of small diameter brush.


If the label indicates potential for volatilization, don’t use when temperatures are in the 80’s or higher.


Don’t apply oil based solutions when ice is on the ground because the herbicide will readily move off-target.


See the woody plant section for more.


Dealing with precipitation

Some labels don’t specify rainfastness.  Rain too soon after application can reduce efficacy & potentially cause off-target kill due to runoff.  I shoot for 8 hours rain-free after application but that may be overkill.  Basal bark requires a few days rain-free (see woody plant section).


“I have a pair of chemical gloves from a home improvement store & I’m careful not to walk in sprayed areas that are still wet.  Good enough?”

I’m afraid it isn’t.  We have to think about long term exposure to any type of chemical, whether it’s in our everyday life or while herbiciding.  The reason to wear protective equipment is not because herbicides are highly toxic, but instead as an insurance policy to keep exposure to a minimum over many years of use.  The degree of exposure for yourself is a personal decision, but if non-applicators are present while the herbicide is wet, assume they want zero exposure.  I’d like to hear from others on how they ensure volunteers at group events never walk into wet herbicide.  Do you have a systematic way for applicators to follow the brush cutters?  Or do you delay herbiciding until the area is clear?  If the latter, how do you find all the stumps if they are small & hidden in vegetation?


How to determine toxicity

The herbicide label contains a signal word from most to least toxic in this order: danger, warning, caution.  Try to use the least toxic herbicide, but as a point of reference, household bleach & toilet bowl cleaner are labeled “Danger”.  If the label recommends chemical resistant footwear or an apron for mixing/loading, consider substituting a less toxic herbicide.


If you hear about court cases regarding herbicide toxicity, research may reveal the plaintiff is not directly claiming the herbicide caused a disease or you may find the majority of credible scientific studies don’t support the plaintiff’s claims.  Public & media understanding of science is poor, so juries are easily swayed by pseudoscience or their own antagonism against corporations.  Any claim that an herbicide caused cancer in an individual cannot be proven beyond doubt because so many things can cause cancer, it’s impossible to know the relative contribution of a given substance.  


What is the most risky activity?

Mixing & loading because you are working with undiluted herbicide.  Always wear chemical resistant gloves & some form of eyeglasses, pour liquids from below eye level, block the wind from blowing the liquid stream around, have paper towels & water available to cleanup spills & have a bottle designed for eyewashing available, filled with fresh water.


Tips to minimize exposure

I’m not a fan of having open herbicide containers at the job site (e.g. using a paintbrush or roller) due to the potential for splashing or spilling on clothes or shoes with no means of immediately showering & changing clothes.  The practice also increases the odds of getting it in your eyes.


Always wear some form of eyeglasses when using sprayers in case the trigger is accidentally depressed with the nozzle pointed at you.


Check state law, rules from your managing agency & the herbicide label to see if posting of signs is required in non-agricultural, non-landscaped areas.  If herbiciding near active trails, you should post signs directing people & their pets to stay on the trail.


If you offload herbicide into a smaller container, always remove the original label of that container & relabel with herbicide name & concentration.  Obtain containers that don’t look like they could hold food or drink.


Chemical resistant gloves

They are not a barrier, but instead slow down the process of chemicals migrating through the glove to your skin.  National Institute for Occupational Safety & Health says chemical protective clothing should be the last line of defense, not the first.  I don’t recommend regularly contaminating gloves with diluted or undiluted herbicide because by the time you rinse them, some herbicide has likely entered the glove material & will be making its way to your skin.


  • Material: I couldn’t find breakthrough time data (time it takes for chemicals to travel through glove material) for herbicides we use.  Schwope1 found that solvents (like those in Garlon 4 & bark oil) will break through the glove material sooner than most other chemicals & will take the other substances with them in the process.  A generalization of their findings is that butyl rubber, nitrile rubber & PVA, all about 15 mils thick, were the best.  Natural rubber & PVC were not recommended.
  • Thickness: Never use thin disposable gloves.  I’ve found 15 mil thick nitrile gloves are a good balance between cost, dexterity, availability & chemical protection.
  • Maintenance: Illinois Dept of Agriculture & herbicide labels recommend washing gloves after every use, probably partly due to breakthrough time & partly to prevent contaminating your skin during donning & doffing.  I replace gloves after 10 days of use or monthly (whichever comes first) to guard against eventual herbicide migration to the inside & potential degradation of the glove by physical movement & ultraviolet rays.  If I accidentally get undiluted product on them, they are discarded.


Why should I read herbicide labels when most of it is aimed at farmers?

  • The label is the law.
  • It gives the maximum application rates to avoid off-target kill & pollution of the environment.
  • It gives application rates to control particular weeds.  If you don’t see your weed on the label, there may be one listed in the same plant family to give you a starting point for concentration.  Please don’t exceed these rates.  More herbicide concentration is not necessarily better.  For example, higher concentrations can kill leaves too quickly, preventing translocation to the roots.  What if the label doesn’t mention spot spray but instead recommends amounts in quarts/acre?  Assume you are using a 3 gallon backpack sprayer calibrated to 40 gallons/acre (see the backpack sprayer section for how to calibrate) & the label calls for a maximum of 5 quarts/acre or 1.25 gallons/acre for your weed.  So to spray 1 acre you will use 1.25 gallons of product in 40 gallons of spray.  1.25/40 = 3.1%.
  • It states how toxic the herbicide is & what protective equipment you must wear.
  • It has valuable information such as use around wetlands & how persistent it is in the soil.
  • Labels can change so download the latest one at regular intervals.


Spray additives

  • Adjuvants: These include oil concentrates like methylated seed oil (creates better penetration of leaf surface-I use this in all my applications), surfactants (causes water to spread on the leaf instead of beading), water conditioners (offsets the negative effects of hard water on herbicides like glyphosate) & stickers (increases the ability of chemicals to stay on the leaf, leading to better rainfastness).
  • Dye: Always use it because it alerts you to missed plants, prevents walking into sprayed areas, alerts you to leaks in the sprayer & makes it apparent if herbicide accidentally gets on your skin.


Backpack sprayers

  • A sprayer setup for those without a pickup truck is shown below.  The herbicide tote contains dye & herbicide offloaded into small, easy to handle bottles along with nitrile gloves, measuring cup & paper towels.  For transport, the sprayer is put into a large plastic tote with a pvc pipe bolted to the inside, which holds the sprayer wand.  Bungees are used to hold it down.  To keep things clean, a plastic baggie is wire tied over the nozzle during transport.


Portable backpack spraying setup


  • Shoulder straps are hard on the body so I bought a harness that transfer some of the weight from shoulder to hips.  Unlike hiking backpacks, they are poorly designed & often need to be modified to fit well, but are still well worth it.
  • Be situationally aware & walk slowly because the sprayer throws your center of gravity off.  If you trip, step in a hole or lose your balance, the added weight of the sprayer can turn a minor injury into a major one.
  • Get in the habit of engaging the trigger lock when not spraying to avoid accidental discharge.
  • Hold the spray wand upright as you walk to prevent drips.
  • As you walk, the sloshing herbicide can leak from the filler cap.  Yep, it has happened to me-right down my back.  First, look at the cap gasket to make sure it isn’t twisted from the factory.  Buy gasket grease from the manufacturer & use a Q tip to apply it every month.  This will help the gasket remain soft & seal better.  Obtain a white sock made from absorbent material & cut a few inches wide section from it.  Each time you screw the cap onto the sprayer, stretch this sock section over the cap so it rests just below the bottom edge of the cap.  This will absorb leaks & will alert you to the need for gasket maintenance by dye discoloration of the sock.  Walking slowly & steadily when the sprayer is full will minimize herbicide splash into the cap area.  Never lean forward since that can cause herbicide to leak from the cap vent hole on some sprayers.
  • You can wear a fanny pack across your chest or gear vest to carry cellphone, gps, maps, first aid, cleanup kit for sprayer leaks, water, food, etc
  • For some sprayers, every few weeks use nitrile gloves to unscrew the nozzle over a drip catcher.  There may be a small screen in there that can be rinsed or wiped clean.  During disassembly, note the order & orientation of the nozzle components so you can put it back properly.
  • At the end of the day, I put a little water in the sprayer & spray that out, then hold the sprayer up high to get all the herbicide out of the hose & wand.  I don’t know if this is necessary, but I never have clogged sprayers.
  • Calibration
    • Labels don’t always tell you how much product to use per gallon of water by volume.  Instead they tell you how much product per acre to use.  That’s because herbicide customers are mostly farmers & landscapers who spray large areas with herbicide mixed in a big tank.  In contrast, we spot spray with handheld or backpack sprayers.
    • This process must be repeated for every nozzle you intend to use.  You’ll need a tape measure, a way to measure time in seconds & a clear container marked in ounces.  Put a gallon of water into the sprayer.  Find a spot where it is safe to spray herbicide & mark a small area such as 20’ x 20’.  Measure how long it takes to spray that area with the same sprayer pressure & height above ground that you typically use.  Spray enough to wet the vegetation but not to the point of dripping.  Now, refill the sprayer if necessary, spray into the container for the same amount of time & measure how much liquid is in the container.  First, convert your test plot into acres by dividing square feet by 43560.  For this case: (20’ * 20’)/43560 square feet per acre = 0.00918 acres.  Let’s say you collected 56 ounces in the container.  56/128=0.4375 gallons.  So you sprayed at a rate of 0.4375 gallons/0.00918 acres = 48 gallons/acre which is ballpark for a backpack sprayer with a hollow cone nozzle.  If we use Garlon 4 as an example, the recommended application rate for broadleaf weeds is 1-4 quarts product per acre.  If we choose 2 quarts/acre, that means we will need 2 quarts product in every 48 gallons of spray or 0.0417 quarts/gallon.  1 quart is 32 oz so that is 0.0417 * 32 = 1.3 oz product per gallon of water or 3.9 oz of product in a 3 gallon backpack sprayer. 


Some herbaceous weeds

  • Crown vetch (CV): See the 7/5/23 post on this blog.  Herbicides used most often are Transline & Milestone, but be aware both are persistent in the soil & will harm some natives.  The Milestone label has a good list of the plant families affected by it.  The manufacturer (Corteva) recommends Milestone over Transline & the latter’s label doesn’t include CV as a controlled species.  Multiple sources, including Corteva, report reduced herbicide effectiveness at bloom stage.  It’s important to coat as much of the stem & leaves as possible.  GPS is essential for not missing patches.  Tom Wise (Military Ridge Prairie Heritage Area in southern Wisconsin) reports that the number of years to control a patch is highly variable & can take 5 years or more.  He sprays known patches before blooming & for ones found at bloom stage, he rotary mows them into tiny pieces to prevent re-rooting & seed set, then sprays after it resprouts.  That method may facilitate better herbicide coverage of all stems/leaves & may also reset the plant into active growth stage, when herbicides are more effective.  Then again, it’s conceivable that mowing could create stem fragments that can re-root.  Losure2 found no viable seed in mature CV patches & cited other sources that support mostly vegetative reproduction.  They also found that stems without nodes won’t root themselves but stems with nodes will.  So it’s unclear whether CV persistence after spraying is due to poor translocation to the entire root system, persistent seedbank, leaf/stem defenses that prevent herbicide entry or unsprayed nodes rooting themselves.  More long term experiments are needed.
  • Garlic Mustard: See the 5/10/23 post on this blog for my method in mostly degraded woodland without the resources to perform consistent mechanical control on a large site.  In summary, after many years of experimenting, I settled on spraying small patches of 2nd year plants at full bloom & fall spraying moderate patches of 1st year rosettes, combined with cutting or pulling scattered or unsprayed plants.  Large patches are left alone to see if a biocontrol develops.  In higher quality areas, I only sprayed rosettes when natives were dormant.  Many broadleaf herbicides & glyphosate are effective.
  • Spotted knapweed: I believe herbiciding followed by wacking/cutting of missed plants is better than wacking/cutting alone for large populations in average quality or degraded areas.  This is because seeds can remain viable for 7+ years & the plant can live up to 10 years.  That means many years of wacking/cutting without missing a year, while also dealing with other weeds like sweet clover, something many sites will find hard to pull off consistently.  Also, stems tend to lie down in the vegetation, making them easy to miss while wacking.  Digging the root is an alternative to herbicides, but its labor intensive & often a large clump of soil comes out with the lateral roots, creating disturbance that leads to more weeds.  It’s best to spray after a burn for better visibility of rosettes since they are hard to find in vegetation or thatch.  Herbicides used most often are Transline & Milestone but be aware that both are persistent in the soil.  The Milestone label has a good list of the plant families affected by it.  
  • Wild Parnsip.  Combine spring (early to mid May) & fall (late Sept-Oct) herbiciding of rosettes with summer digging of the root.  Spraying too early can result in missing late emerging plants.  Soil temperatures will influence emergence dates in the spring.  Spraying after a burn will ensure finding more rosettes.  Mature invasions in areas with weak native competition or poor soil microbial diversity can take >4 years of effort.  Flowering usually occurs in the 2nd to 4th year of life, so herbiciding rosettes is effective in targeting multiple generations.  Delayed emergence creates a long blooming season requiring 2 passes of digging separated in time, which is another reason herbicides are helpful.  Many herbicides will work.  After 2 years of use, I’m happy with 0.5% Garlon 4 in water with 0.5% methylated seed oil.  0.5% Garlon 4 worked as well as 1% in an experiment I conducted.


Woody plants

  • See other discussions on this blog.
  • Commonly used herbicides are 20% active ingredient glyphosate in water or 20% Garlon 4 in bark oil, applied in winter or when native herbaceous plants are dormant.
  • Clonal plants:  These include dogwood & sumac.  Treat a given clone all at once rather than piecemeal.  A few years of treatment will often be necessary to kill the root system, especially on older clones.
  • Methods include
    • Cut stump or cut surface.  The stem is cut as close to the ground & as horizontally as possible, then the stump is herbicided as soon as possible.  If performed in that way, it is the most reliable method for controlling woodies, but is also the most labor intensive.  There are reports of cut stump herbicide failures with certain plant species, but there are also plenty of reports that glyphosate & Garlon 4/bark oil work just fine for all woodies (which is also my experience).
      • It avoids having standing dead brush, which can be an impediment to controlling weeds after removal of dense brush clones, a deterrent to grassland bird nesting or an eyesore in some situations. 
      • Stems cut at a strong angle will have too much herbicide runoff.
      • If snow forces you to cut higher than normal, be prepared for poor control.  Don’t let snow deposit on the cut stump or herbicide will get diluted or run off.
      • If you can’t spray soon after cutting (for example, waiting for volunteers to leave the area), favor Garlon 4 over glyphosate.  Glyphosate based labels say to spray immediately after cutting, but I found Roundup effective in shady habitats on good sized buckthorn even with a 2 hour delay between cutting & herbiciding3.
      • Note that painting the stump with a roller, brush or sponge may not apply enough herbicide to be effective, so experiment before settling on that method.  It’s interesting to note the Garlon 4 label mentions spraying for cut stump or basal bark but not rolling or painting, perhaps an indicator that those methods are not consistently effective.
    • Basal bark.  The stem of the uncut plant is coated in herbicide (typically 20% Garlon 4 in bark oil) from the ground to a particular height based on stem diameter & plant species.  The oil helps the herbicide penetrate through the bark.
      • If significant rain falls within a few days after application, runoff can cause off-target kill.
      • You may have a dead zone around the treated plant if the herbicide is applied in spray form.
      • As with cut stump, painting or rolling onto the bark may not transfer enough herbicide compared to spraying.
      • It’s best to conduct an experiment to verify that your choices for the application dates, amount of bark treated, application method & herbicide type/concentration is effective on all species of interest before you treat large areas.
    • Cut stump & basal bark off-target kill.  There are reports of this (see 8/28/20 entry on this blog) but many others report no such problems.  The cause is unclear, but possibilities include root exudation of herbicide into soil4, movement of herbicide by mycorrhizal fungi, rain runoff, application error or exceeding the labeled maximum use rates.
    • Foliar spray.  The leaves are sprayed on shrubs, small seedlings or resprouting mowed/cut brush in degraded areas or if the woody plant is leafed out while the native ground layer is dormant.  This can be a very risky method.  Usually large areas need to be sprayed with the nozzle far above the ground, which increases the possibility of wind drift onto the applicator & the ground layer nearby.  There are plenty of reported failures with foliar that may be related to herbicide concentration/type, species of woody plant or season of application, so conduct a 1 year experiment before treating large areas.
    • Frill.  Cuts are made in the bark & cambium around the stem using a hatchet or similar tool, then sprayed with herbicide.  See other posts on this blog.
  • Spray equipment
    • Handheld sprayers


Handheld sprayers L-R: lower quality Hudson 62227, high quality Tolco 942


      • Drawbacks are the need to stoop very close to ground level & the weight combined with pulling the trigger all day is hard on your hand & wrist.  Stooping risks eye or nose injury in dense brush clones.
      • Avoid the cheap ones at brick & mortar stores.  If they don’t leak from the get go (often from the pump shaft if you tilt the bottle too far off vertical), they will leak or fail sooner rather than later.
      • See
      • 2 quart capacity is necessary for a full day of cut stump without refilling.
      • To keep the bottle outside surface free of poison ivy & herbicide when working alone, place it in a 5 gallon bucket when not spraying.  Use spacers of some kind to place the sprayer in the bucket such that the nozzle sits over a drip catching tray.
    • Standalone sprayer
      • Advantages are no stooping required, the trigger is easy on your hands/wrist & a wide selection of nozzles are available.
      • I put the sprayer in a bucket as shown below.  Without the bucket, the sprayer will tip over on uneven ground & can become contaminated with poison ivy & herbicide.  It also makes working alone much easier.  I can spray some stumps soon after cutting so all can be found, hang the sprayer wand on the coat hook, cut some more stumps with loppers, then spray again.  The nozzle I use is a single stream type, which is just a cylindrical tube.  With low pressure, a light hand & a hose clamp trigger stop, I can place the nozzle against the stump & flow just enough herbicide to prevent drippage onto the soil.  


Woody plant spray fixture for working alone.  Sprayer is Smith 190504.



1) Schwope, A. D., etal, 1992, Permeation Resistance of Glove Materials to Agricultural Pesticides.  AIHA Journal 53(6):352

2) Losure, D.A., K.A. Moloney and B.J. Wilsey. 2009. Modes of crown vetch invasion and persistence.  American Midland Naturalist 161:232–242.

3) Osmund, D., 1997, Cut-stump treatment of buckthorn effective despite two-hour delay between cutting & spraying (Illinois).  Restoration & Management Notes, 15(2): 197.

4) Graziano, G, etal, 2022, Herbicides in unexpected places: non-target impacts from tree root exudation of aminopyralid and triclopyr following basal bark treatments of invasive chokecherry (Prunus padus) in Alaska.  Weed Science, 70(6): 701-714.


Monday, August 21, 2023

Celebrate With A Purpose!

This post is now history. It advertised the weekend that celebrated the 60th anniversary of the influential  Illinois Nature Preserves System. Dozens of events, August 26th through 28th, 2023. 

Come and be counted. The 60th Anniversary of the Illinois Nature Preserves is important to their future. Remember how ecosystems cried out for help ... and how that help increasingly arrived, thanks in part to volunteer energy and Friends of Illinois Nature Preserves. Vacant staff positions are being filled. Volunteer stewards perform wonders. Funding may not be increasing enough. But it is increasing. Why? Because people care, and we demonstrate it. This weekend is your opportunity to be seen on the side of the good guys and nature.

Perhaps this weekend is your opportunity to invite a friend who knows you speak passionately about your favorite ecosystem but can't figure out why.  Let's take this opportunity to grow the community of people like us who know and love and care.

Saturday, August 26, 2023: You can choose among 30+ Nature Preserve tours in every corner of the state. Find one close to you on the Friends' map of events here, and help us plan with an RSVP. 

Sunday,  August 27 (Free - but limited space - RSVP required):

2 PM Gallery opens. 3 PM: Respected as both artist and naturalist, Philip Juras leads a gallery talk "The Long View", based on 23 Illinois Nature Preserve paintings on display at the Illinois State Museum in Lockport followed by: 

4:15 PM: Reception and celebration at the historic Gaylord Building, just up the street. 

Monday, August 28

2 PM: A celebratory Illinois Nature Preserves Commission meeting at Illinois Beach State Park lodge with speeches by Arthur Melville Pearson, author of Force of Nature, Brian Anderson, former Nature Preserves director and Amy Doll, director of Friends of Illinois Nature Preserves. 

followed by:

3:30 - 6:00 Celebration, reception, refreshments, and more (Free - but limited space - RSVP required)

4:00, 5:00, and 6:00: One hour hikes and tours led by Stephen Packard and Eriko Kojima

And, whether you can come of not, you might want to donate to the Friends

The Illinois Nature Preserves System has been and should forever be a global model. As a state where only 7/100ths of 1% of true nature survives, we are stopping the losses and restoring health, quality, and extent at an inspiring scale. We celebrate and spread the word for good reason: When people know, they care, and many act. 

This photo of the very first Nature Preserve, Illinois Beach, is a valuable reminder. We don't want to lose it. We do want to treasure, heal, and expand the nature that survives. For the planet and ourselves. 


This post illustrated by photos generously donated by:

Michael Jeffords and Sue Post: fringed gentian (it needs wet prairie associates).

Lisa Culp Musgrave: Red-headed woodpecker (it needs savannas and open woodlands).

Mike MacDonald: Illinois Beach Savanna (saved again and again by public-spirited citizens and the Illinois Nature Preserve System). 

Thanks for proofing and edits to Eriko Kojima, Amy Doll, and Robb Telfer.