Yucca Removal Success

I took a little time to evaluate the success of my earlier efforts to eradicate Yucca from my fields.  Dead stumps where I had cut the stem and applied glyphosate to the exposed tissue.  This photo was taken in October, about six months after herbicide applications were made.  In most cases, there seemed to be a total kill of Yucca plants.

In a very few cases, there was some regrowth, but regrowth was not the normal situation.  It won’t take a lot of effort to go through to cut and spray the young shoots.  For the next few years an annual check will have to be made to find new plants growing from seed.  New plants will be a possibility for quite some time, but it should be fairly easy to keep the area practically Yucca free.

I only had time to cover about two-thirds of the Yucca infected area before I had to move on to higher priority management activities.  I finished my work in the open field and then began working my way down a cedar filled waterway.  This is where I stopped and this is where I will begin next March.  Weather permitting, I will have eliminated Yucca from the area by next April 1.

One thing I hadn’t expected was the ability of the cut plants to continue growing.  This is what my plant pile looked like after six months.

 

The Whitetail Deer treat it as a salad bar.  I never saw this much deer browse on the Yucca in the field.  Young Yucca shoots must be more palatable to the deer.

Pulling a shoot out of the pile reveals white roots growing from the cut stem.  This illustrates a good reason for removing the cut plants from the field as they are treated.  The Yucca may flourish in the pile for a couple of years, but I am always adding to these piles, so the plants will eventually be covered and smothered by other plant material.

 

Yucca Removal

Yucca, Yucca filamentosa, has slowly been encroaching on one of my prairie areas.  Yucca filamentosa is a North American native plant originally confined to the south-eastern portion of the United States.  It is considered to be a naturalized species in Ohio, with populations generally spreading from sites of human habitation where Yucca was planted for such uses as food, medicine or ornamental purposes.  Since I manage for native populations, the Yucca, non-native in my area, has always been on my list of plants to eradicate, but there have always been more serious matters for me to deal with.  A few years ago I began to notice new Yucca populations popping up hundreds of feet from the original infestation.  That discovery caused me to move Yucca removal to a higher level on my priority list.  After a couple of years testing treatment methods, I began in March 2020 to eliminate Yucca from Blue Jay Barrens on a large scale.

The long pointed leaves have fibrous strands that give the plant a rather worn look.  These are the filaments from which its scientific name derives.  The leaf edges can sometimes be abrasive and the leaf tips are often sharp.  I got plenty of scrapes and pinpoint wounds while dealing with this plant.

The vertical stem is generally quite short, but can sometimes reach up to a foot in height.  The leaves grow in a whorl from the stem with new growth coming from the tip.  The old leaves die to form a thick mulch that eliminates any competing plants from growing near the Yucca.

Here is the point of original infestation.  This open hilltop allowed for seeds to easily spread down hill.

I thought the origin site to be an excellent beginning point for Yucca eradication.  Especially since I have a well used walking trail running along the edge of this area and I was tired of seeing Yucca every time I went by.

From the top of the hill, Yucca spread down the slope to the west.

With this area cleared, I really had to stretch my neck to see any Yucca from the trail.

Yucca spread out near the base of the hill.  All cut Yucca plants were moved to a brush pile seen just to the right of the center of this photo.

At this point, all Yucca plants in the prairie area have been removed.  Those plants showing on the right side of the photo were removed the day after this picture was taken.

 As I cut off the Yucca plants, I piled the tops for future collection.

Cut plants were loaded onto a tarp and dragged out of the field.  Fortunately it was a down hill drag to the brush pile.

This pile, roughly six feet high and twelve feet wide, was made of plants cut from about one acre of prairie.  The pile will quickly shrink in size as the plants decompose.

Deer will generally not browse Yucca plants.  However, they seem to very much like the stems and treat the brush pile as a huge feeding station.  Individual plants are pulled out of the pile by the deer. They dine on the normally unreachable stem and leave the tops strewn about, sometimes a long distance from the pile.  Cut Yucca plants will easily root and continue growing if left on the ground, so I have to periodically gather up the tops and replace them on the brush pile.

I’ve removed Yucca from about one and a half acres of open prairie.  I still have about a half acre of Yucca growing in a shaded drainage area.  Other priorities have temporarily taken me away from this work, but I hope to continue the Yucca removal job later in the summer.  At a minimum, I will cut the flower stalks to eliminate seed production for this year.

A clump of mature Yucca plants appears to be a formidable adversary, but pushing aside the lower leaves reveals a soft underbelly.  Although the stems may reach a diameter of two inches, they are very soft.  I had no trouble slicing the stem with a pair of standard hand pruners, often severing the stem by simply pushing the pruner blade on through.

Removing the cut plant reveals the severed stems surrounded by a dead zone resulting from shading by the Yucca leaves.  In some of the larger clumps, lateral stems were poised to add to the size of the colony.  All parts of the stem in contact with the ground produce roots, so each new stem could become a standalone plant.  The roots are reddish in color and can be seen near the cut stems.

After cutting, I applied concentrated glyphosate, typically a 41% solution, to each cut stem.  Not knowing if the glyphosate would effectively eliminate the developing stems, I cut the tip from each young stem and treated it with glyphosate.  In my earlier trials, this method proved to be nearly 100% effective in killing the entire plant.

I treated a wide range of plant sizes.  Large plants were the easiest to find, cut and treat.  Smaller sized plants, such as that shown just below the large cut stem in the photo, were harder to locate.

Over the next few years I’m sure to be dealing with many small plants that evaded my search, but I’m sure the days of a widespread Yucca invasion are over. 

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.

Eliminating Invasive Plants – Summer Activities

As the seasons change, my management activities change.  Summer is a time to hunt and eliminate invasive forbs and grasses.  Sweet Clover was my initial target several years ago.  As Sweet Clover numbers dropped, I added other species that could be controlled by pulling prior to setting seed.  Now, Yellow and White Sweet Clover, Wild Carrot, Teasel, and Oxeye Daisy are all on my summer pulling schedule.  Not all invasive species can be controlled by pulling.  Sometimes, like in the case of Crown Vetch, the aid of a chemical herbicide is necessary to eliminate the plant.

This is my second year using the chemical Clopyralid in the treatment of Crown Vetch.  Clopyralid kills only broadleaf plants, and is particularly effective on legumes.  Grass is left unharmed, so no bare spots are left in the field after treatment.  The areas I treated this year were fewer in number and much smaller than what I dealt with last year.  Shown above is the largest patch of Crown Vetch I had to spray this year, and it covered only about 40 square feet.

Crown Vetch found its way into my fields as seed that was produced along the edges our township road.  I eliminated the roadside vetch last year, but some of the affected field areas are going to take a bit more work.  Crown Vetch growing beneath the canopy of tall Indian Grass is hard to spot.  The best time to search is when the plants begin to flower.

Unfortunately, peak flowering time for Crown Vetch coincides with flowering of other lavender bloomed plants such as Monarda.  Shown above is Crown Vetch on the left and Monarda on the right.  Colors are almost identical.

Monarda flowers are held above the Indian Grass leaves.  Good luck trying to spot a couple stalks of Crown Vetch hidden down in the grass.

Johnson Grass is another species that requires some herbicide assistance if it is to be eliminated.  I’ve been after this species for several years and only found seven small clumps growing this year.

When dealing with Johnson Grass, I first cut the stalks down to a manageable height and trim back any long, flowing leaves.  This allows me to spray the complete plant with glyphosate, without spraying a lot of neighboring plants.

Johnson Grass is another invasive species that can trace its origin back to the roadside.  Even though the roadside along my property is free of this invasive grass, seed produced along other sections of the road are easily caught and transported by vehicles traveling the roadway.  I expect passersby will replenish my seed supply on an annual basis.

Johnson Grass is hard to miss when it sends up a flower stalk.  This species puts on height in late July, long before the tall prairie grasses, so it doesn’t take much searching to identify new infestations.

When the plant is blooming, tops can be cut and just left in the field.  There is no chance that these flowers will produce viable seed if removed from the plant at this stage.  If treatment is done after seed has formed, it is best to remove the seed heads from the field to eliminate any viable seed being left behind.

I began pulling Wild Carrot six years ago.  I’ve had a lot of success in reducing the numbers of this plant.

Areas that once yielded hundreds of plants, are now producing only a few plants each year.

With fewer plants to pull, I can cover more area.  This is the last of the Wild Carrot infested barrens, an area that I have never had time to get to before.  I was able to finish off this field just as the pulling season came to a close.

Wild Carrot seeds were just beginning to darken during my last week of pulling.  Not knowing if these seeds were developed enough to finish ripening on a pulled plant, I removed the seed heads and bagged them for disposal somewhere other than the middle of my field.

A single Black Swallowtail caterpillar was found on one of the pulled carrots.  I transplanted it to a domesticated carrot variety in my vegetable garden.  It ate for several days and then disappeared.  I hope it went off to find a secure place to pupate.