Fall Project 2017

Each year during September and October, I tend to embark on a large scale management project at Blue Jay Barrens.  This year I worked to systematically eliminate all invasive shrubs from a 16 acre block that was historically used as a crop field in the early 1900’s.  Since all invasive shrubs of seed bearing age appear to have been eliminated from the property, I thought the next step should be to aggressively pursue the youngsters.  My primary problem shrubs are Multiflora Rose, Bush Honeysuckle, Japanese Barberry and Autumn Olive as shown in the lineup in the photo above.  I also find a few Privet and a couple of Winged Wahoo.

My project area sits on a long south facing slope and is a roughly rectangular shape measuring 900 by 800 feet.  The area is currently a patchwork mix of large Eastern Red Cedars, mixed hardwoods, and barrens openings.  I began work at the east property line and worked my way west in a series of strips paralleling the fence line. Each strip ran from the creek up to the hill top, an elevation difference of about 140 feet.  The neighboring property has a growing population of invasives and birds bring plenty of seeds across the property line.  Invasive shrubs were especially prevalent within 100 feet of the fence.

To make my search as thorough as possible, I produced a grid pattern by using marking flags to establish the strips and to show the corners of each cell within the strip.  Strips were about 20 feet wide and each cell was about 35 feet long.  This resulted in around 1,000 cells developed within the project area.  I began by establishing two strips using three lines of flags; one red, one blue, and one yellow.  As I completed each strip, I would move the line of flags west to make a new strip.  Within each cell I would walk a line about three feet in from the side, cross over at the end and walk about three feet in along the other side, and then travel up the center until I reached the next cell.  There’s no place within that 16 acres that I wasn’t within a few feet of while searching.  Every invasive shrub found was cut off at ground level and the resulting stump treated with glyphosate.  Most of the treated individuals were less than two feet tall.  If I could see it, I would treat it.

Of course, that doesn’t mean I found every invasive shrub there was to find.  Surrounding native vegetation often hid the invaders.  Dappled sunlight could also be effective camouflage.  Despite these obstacles, I drastically reduced the number of unwelcome shrubs.

Even shrubs that appear impossible to miss can be hidden from view.  This Bush Honeysuckle could not be seen from the other side of the tree.

The concentration of invasives was greatest beneath trees used by roosting or resting birds.  The photo above shows an Autumn Olive, a Bush Honeysuckle and a Multi-flora Rose, three of a larger collection of similar specimens all inhabiting the same small area of ground. 

The cause of the infestation was a large Sycamore, the trunk of which can be seen here in the background.  Flocks of Robins and Cedar Waxwings seem to spend considerable time in the upper branches of towering Sycamores, often after making a large meal of fruits from surrounding shrubs.  While resting, they are also dropping seeds into the fertile soil beneath the tree.

It’s common to find a clump of seedlings that has developed on the site of a seed filled bird dropping.  This jungle of Autumn Olive seedlings resulted from a single bird drop.  

The seedlings must now compete among themselves for survival.  The plants at the edge of the cluster stretch out to capture sunlight.

The clump may appear to be spread over a rather wide space, but clipping the tops reveals that all stems are originating from a single small spot.

Invasives were cut and treated in this area in a slightly less intensive search conducted four years ago.  These two Bush Honeysuckle stems and the stump from which they were cut are a result of that management effort.  I was concerned when I found many Bush Honeysuckle seedlings growing in a roughly 10 foot diameter circle centered around the dead stump.  Could seeds from fruit that fell uneaten to the ground germinate after several years of natural stratification?  If so, this could cause another complication in the battle to control these invasives.  Hopefully, this is just the result of some seed laden birds that just happened to roost above this old bush site.

Multiflora Rose growing on the dry, rocky slopes show an interesting growth pattern.  Most have been growing for many years as indicated by the thick stump found at ground level, but the plants display only the current year’s growth.  Dieback due to harsh conditions seems to be a perennial problem for these roses.  That doesn’t stop them from trying anew each year.  The plant shown above has one live stem produced this year, one dead stem produced last year, and numerous scars on the stump from previous years.

Multiflora Roses also have a habit of sending out a horizontal stem that stays hidden from view.  Cutting and applying herbicide above this branch could cause the treatment to fail and the rose to survive.  The horizontal branches also have the annoying habit of rooting at the leaf nodes so that a series of individual plants develops along the length of the stem.

I know the property will never be completely free of invasive plants, but it would be nice to reach a point where I could walk around without having their presence so obviously displayed everywhere I look.  As my supply of non-native invasive shrubs dwindles, the populations on neighboring properties is expanding, so new seeds will always be finding their way across the fence.  At one point during my work, I was thinking of one of my favorite books, The Day of the Triffids by John Wyndham.  I didn’t realize it when I read the book for the first time nearly 50 years ago, that the story is basically about a non-native invasive plant species that swarms over the countryside wreaking havoc on the human population.  At one point in the book, Triffids crowded outside barrier fences while the people inside hunted and destroyed any invading seedlings.  It was the scene just outside my fence line that brought that book to mind.  Of course, the invasive plants that I’m dealing with can’t walk and they’re not going to strike me dead if I exhibit a moment of carelessness.  That’s something I can be grateful for as I continue my work.

Invasive Control - Crown Vetch

I made an effort this year to seek out and spray colonies of the invasive Crown Vetch.  For several years now, I’ve been finding random clumps of this invasive plant scattered about Blue Jay Barrens. 

My efforts began last autumn when I mowed several Crown Vetch infested spots in the field. I returned to those spots in April to spray the early season growth.  I also targeted early season growth between the township road and my field fence.

I elected to use the chemical Clopyralid as a control agent.  Clopyralid is a selective herbicide that targets broadleaf plants, especially legumes.  Unlike glyphosate, which kills all green growing plants, Clopyralid leaves grasses unhurt, so the treated area does not become a big bare spot awaiting the arrival of new invasive seeds.

Within a week, the Crown Vetch was showing the effects of the herbicide.

A month after that, all traces of the invasive plant were gone.

The light colored area in the background at the upper left of the photo is the township road that runs along two sides of a large prairie opening.  A scattering of Crown Vetch plants, remnants of a government funded planting in the early 1980’s, persisted along the shady lane and produced seed that moved with the rain water to establish new plants along the edge of my field.  Hopefully, that influx of seed will now end.

In late May, I found a large infestation of Crown Vetch in a low area that receives runoff water from the road ditches. 

The vetch was growing at a rate slightly slower than its companion prairie forbs, making it difficult to see from a distance.  Fortunately, I was in the area doing some other work and just blundered into the middle of the Crown Vetch patch.  The Clopyralid successfully eliminated the vetch from this site, but it also took most of the other broadleaf plants.  That was a bit of a disappointment, but there was plenty of grass left, so the site was not bare. 

By late June, the Crown Vetch was blooming.  Blooming plants are easy to find and I made sure to search in all places likely to have an infestation.

Crown Vetch is aggressive enough to eliminate all neighboring plants.  By using a herbicide that doesn’t result in the elimination of all species, I have left things in better condition than they would have been if left to the mercy of the vetch.  Crown Vetch increases its growing area by using a technique known as sprawling.  Stalks grow upright by using neighboring plants for support.  Eventually, the stalk overtops the other plants and falls over.  The fallen stalks form a canopy over surrounding plants, causing those plants to suffer from shading and become less vigorous.  The affected vegetation eventually dies and the vetch claims this new growing area.  A single patch of Crown Vetch can eventually cover an entire field.

Most of the Crown Vetch clumps covered less than 50 square feet.  Only one was over 100 square feet.  I’ll have to wait until next growing season to what grows back on the treated sites, but I think the use of Clopyralid has had a positive impact on control of the Blue Jay Barrens Crown Vetch invasion.

Treating Invasives

I took advantage of the mild weather during the first half of November to search out and eliminate some invasive shrubs.  Most of what I find now are young plants that have not matured enough to produce seed.  Birds will continue to bring in fresh seeds, and plants resulting from those seeds are what I am primarily dealing with now.  Birds that left seeds on this spot had a varied diet that resulted in a cluster of my four primary target plants.  Clockwise from upper center are Autumn Olive, Multiflora Rose, Bush Honeysuckle, and Japanese Barberry.

Japanese Barberry is a recent invader of Blue Jay Barrens and has not become very well established.  By the time the first Barberry plants began showing up, I had already begun dealing with invasive shrubs.  Only a few got up to fruiting size before they were discovered and removed.  This species is easy to control by stump spraying with glyphosate.  Even a maximum recommended dilution of the chemical is enough to kill the roots.

I’ve still got a couple of small patches that continue to produce a wealth of new Bush Honeysuckle plants each year.  Fortunately, the glyphosate stump treatment quite effectively kills this invader.  It’s discouraging to annually deal with so many new plants, but the sites are small and the number of plants continues to decrease.  Five years ago, the new Honeysuckle growth here was thick enough to block the view of the ground, so I am making progress.  I have to remind myself of that fact each time I work here.

Only one larger Honeysuckle specimen was found this year.  It was roughly six feet high, but was not old enough to produce fruit.  Last year, this shrub would have been only two or three feet tall and would have been easy to miss in its position on the lower slope of the creek bank.  I don’t mind finding an occasional large plant, as long as I catch it before it has a chance develop fruit.

Autumn Olive is the most difficult shrub to control at Blue Jay Barrens.  I use a stump treatment of undiluted glyphosate 41% concentrate solution.  This method is quite effective as long as the plant being treated is displaying healthy, bright green leaves.  Once the leaves begin to yellow and drop, it becomes more difficult to get a good kill.

Older, fruit bearing  Autumn Olive specimens can be killed by the same stump treatment, but there is a high likelihood of root sprouts appearing the next growing season.  It may take a couple of years to eliminate the sprouts.  Seedlings also tend to recur for several years following the death of the large shrub.  Birds feeding on the fruit, drop some of the seeds from the previous day’s feast.  Some of these seeds are ready to sprout immediately, while some may wait through a few seasons before germinating.  The good thing is that no matter where the new plants are coming from, their numbers tend to lessen with each passing year.

Autumn Olive can grow so rapidly that they sometimes seem to appear from nowhere.  This area of Indian Grass was mowed last November.  Small Autumn Olive plants, hidden in the thick grass, were cut off a few inches above ground level.  With a healthy root system already in place, the regrowth from those cut stems reached six or seven feet high in one season.

This is what the base of that plant looked like.  The dead stub in the center of the stem cluster is the single stem that was cut off last year.  It’s obvious that mowing is no way to control Autumn Olive.

To effectively treat young Autumn Olive, you must cut the stem flush with the ground.  The problem is that the stem you see may not be rising directly above the root.  Autumn Olive commonly produces a horizontal stem that later gives rise to the aerial branches.  This horizontal stem is often hidden by thatch or neighboring plants.  In the photo, the stem to the left was attached to the root and the vertical shoot emerged three inches away.  Cutting and spraying at the base of the vertical shoot would most likely not kill the plant.

I am also beginning an assault on the invasive Crown Vetch.  It was planted along the road about 40 years ago, but only recently has it begun to show up out in the fields. 

I was going to spray the Autumn Olive with Clopyralid this summer, but neighboring vegetation made it impossible to get the spray through to the vetch leaves.  Instead of spraying, I went around and identified the locations of all infestations, about ten in all.  I mowed them this fall and will do my spraying next spring when the vetch begins growing.  I guess I don’t have to worry about running out of invasives to deal with.

Giant Resin Bee

A loud buzzing drew my attention to activity on an Ironweed flower head.  I snuck in close to observe this foraging bee.

Hairless abdomen rules out Bumblebee.  That left me with an identification of Carpenter Bee, but this specimen just didn’t look like the Carpenter Bees I’m used to seeing around the barn and house.  The hair on the thorax was much darker and browner than a normal Carpenter Bee.  I concluded that I was observing a Giant Resin Bee, an introduced Asian species that is spreading quickly across the Eastern United States.

It was really going after the nectar in the Ironweed flowers.

At one point it slipped from the flower and hung belly up.  After a moment, it began using its front legs to rub the ventral side of its thorax.

A few seconds later it slipped farther down and at one point was holding on by a single hind leg.  It squirmed back-and-forth much like a dog will do when it finds something particularly stinky to roll in.  I figured it was in the clutches of either a crab spider or an ambush bug.  I moved in to see if I could spot the predator.

As I leaned closer, the bee snapped back upright and gave me a threatening look.  Whatever its strange behavior had been, it had nothing to do with being snared by a predator.

I pulled back slightly and the bee resumed its foraging.  I’ve never observed a bee that moved so clumsily about on the flowers.  It fumbled around like it had six left feet.  Here it made a belly flop on the flower with its legs hanging free on either side.  Eventually it flew off.  This was an interesting encounter, but I’m never thrilled to add another non-native species to my list of Blue Jay Barrens residents.

Fescue Control Trial

There are over a dozen invasive plant species that are on the priority list for control at Blue Jay Barrens.  For some, I’ve found effective control techniques and those species are slowly being removed from the landscape.  For others, I’m still trying to discover effective control techniques.  One group that I am currently working on is made up of introduced cool season grasses commonly used for pasture, hay or landscape purposes.  The most visible members of that group are Tall Fescue, Orchard Grass, Timothy and Kentucky Bluegrass.  They all begin growth early in the season, slow down or enter dormancy during the heat of summer and revive to grow into late fall.  They are most easily detected in late spring when they overtop slower growing vegetation and send up their flower stalks.

Varieties of all of these grasses have been developed to be super vigorous and highly competitive.  Many native plants cannot survive the competition and disappear.  The challenge is to find a way to remove the invasive grasses from the stand without harming the natives.  I have some ideas and decided to try one out on the grass along the trails.  This is what a typical untreated trail edge looks like.  A secondary reason for conducting my trials along the trail edges was the fact that the mature fescue seed stalks lean out into the trail at the precise time that chigger activity peaks.  Brushing the stalks while walking invariably results in chigger bites, so no grass also means fewer chigger bites.

This point, formed by a fork in the trails, was last year thick with Tall Fescue.  Tall Fescue is the most aggressive of the four grasses mentioned.  Having been used for years for pasture, hay and erosion control, Tall Fescue is present on probably every farm in southern Ohio.  Kentucky 31 Tall Fescue was considered the farmer’s friend and because of its ability to survive on the poorest of soils, is probably responsible for much of the farmland soil remaining on the hillsides.  It’s a tough grass, but it has been eliminated from this small spot and the natives remain.

Last December 2, I used the brush mower to trim down dead stalks along the trail and expose the still green fescue beneath. I then applied a 2% solution of glyphosate to the cut grass.  Since most of the native species were dormant with top growth dead, there was no danger of their being damaged by the herbicide.

The effect of the herbicide is clear to see.  In the treated area the non-native grasses have been eliminated.  The untreated area farther from the trail still has a thick stand of grass.

In a very few areas, the treatment was not successful.  Even though the forecast was for dry conditions throughout the day of treatment, a rain shower hit the area about three hours after the herbicide application.  The spray should have had time to dry and adhere to the grass leaves, but since it was cool and I had just mowed off a large part of the leaf, it’s possible that the chemical was diluted enough to render it ineffective.  It could also be that a clump of cut vegetation covered this patch of grass and intercepted the spray or, even though highly unlikely, the guy wielding the backpack sprayer may have just missed this spot.

I noticed just one native species that did not survive the herbicide treatment.  Golden Ragwort, notorious for maintaining green leaves through the winter, went the way of the exotic grasses.  In this case it was just an area about three feet long that contained the ragworts, but it does illustrate a potential problem with this treatment method.  Any green plant still actively growing will fall victim to the glyphosate.  Before using this method of grass control it is essential that you know what other plants might be susceptible to the spray.  Then a decision can be made as to whether those plants should be sacrificed in order to remove the grass.  In this case, Golden Ragworts are quite common here and will quickly move back into their former haunt.

Other species are taking full advantage of their life without competition.  These Wingstem plants are out to set an all time height record.

The area along this trail used to contain a great stand of Monarda fistulosa.  The Monarda suddenly disappeared a few years ago.  It’s been slowly recovering and shows no damage from the glyphosate treatment.  I’m hoping that a few more years will find it back in its glory.

I’ve tried the December applied glyphosate treatment in the past on small, nine or twelve square foot plots.  One potential problem is leaving bare ground into which invasive plants can get a foothold. This is especially true with extremely thick stands of grass.  If native species cover less than half of the treated area, there is a high likelihood that colonizing weed species will appear on the site.  Teasel, Johnson Grass and Canada Thistle are some that are problems in this area.  Native annuals, such as the Giant Ragweed shown here, also take advantage of the exposed ground.  Giant Ragweed has always been a part of the flora along this section of trail and doesn’t cause me much concern.  It may be a bit more prevalent for a couple of years, but will soon return to its normal scattering of plants.

The native prairie grasses suffer no damage.  Their top growth has already died back by the time the glyphosate is sprayed.

This section of trail shows a healthy Indian Grass border.  The grass will be leaning in and just about closing the trail by September, but it doesn’t bother me as long as it’s native.

The next step in controlling the invasive grasses will be to move away from the trail and into the field.  I’ll monitor the area along the trail through the summer and if things seem to go well, I’ll treat some larger sections of the field this winter.