Advantage: Invasives

Invasive shrubs manage to overwhelm many ecosystems by more effectively exploiting the resources available in their environment.  They are currently busy demonstrating one of the characteristics that allows them to claim such a dominant role in any ecosystem they occupy.  Plants use sunlight captured by green leaf area to fuel the photosynthetic process that supplies the energy needed for plant growth and reproduction.  Invasive shrubs, like the Bush Honeysuckle shown above, produce leaves quite early in the year and hold those leaves into late fall.

Our native plant species have evolved a sequence growth that allows each species to capture the sunlight necessary to its survival.  Spring wildflowers generally complete their growth early in the year and by the time the trees have developed their leaves, the early plants have stored the energy they need to produce seed and carry on to the next year.  At Blue Jay Barrens, the leaves of invasive shrubs develop in advance of most of the early wildflowers and deprive the native species of their needed sunlight.  Eventually, the invasives form a solid thicket and the natives disappear.

The vining Japanese Honeysuckle does the bush type one better.  In some years, the previous year’s leaves remain green through the winter.  The leaves to the upper left are from last growing season and the rest are new to this month.  As long as the leaves are green, photosynthesis can occur.  While native plants are in their winter dormancy, Japanese Honeysuckle grows continually stronger and more able to compete for a place in the landscape.

Autumn Olive is quick to take advantage on the slightest winter thaw.  The long leaf season of these invasives allows them to put on some tremendous growth.  This four foot tall specimen represents only two years of growth.  In that short time it went from a seedling, barely reaching above the leaf litter, to a major producer of shade.

These leaves are the result of about two weeks growth.  The growth will soon begin to elongate into the production of new stems.  The shrub could easily double its height and quadruple its width before the end of this growing season.  That is, it could have if I had not cut it down and sprayed the stump with herbicide.

Seedlings may take a couple of years to develop a root system capable of sustaining rapid top growth.  This seedling managed to hold onto one of its leaves for the entire winter.  The benefits from this one leaf have probably greatly increased its competitive edge.  If I hadn’t cut and sprayed this little guy, it could have reached over two feet tall by the end of summer.

Multiflora Rose is another that is quick to put its leaves into play.  Frosts and freezes may cause some leaf damage to these shrubs, but the damage is generally restricted to shrubs growing in the open.  Shrubs growing beneath the canopy of taller plants are often protected from frost damage.  If some leaves are killed, they are quickly replaced.  All of these species are highly susceptible to a cut stump application of glyphosate during this early growth season.  I usually carry my pruners and spray bottle with me everywhere I go during this time of year.  Fortunately, I am now only dealing with newly arrived invasives, so a pair of hand pruners is all I need for the job.

Powdery Mildew Fungus on Japanese Honeysuckle

Diseased plants are normally a disturbing sight.  My initial reaction when I saw pale, shriveling plants in this jungle of greenery was dismay.  That feeling dissipated quickly as I realized that all of the sickly plants were Japanese Honeysuckle.  Anything that weakens an invasive plant species has got to be good.

Closer examination revealed a velvety covering of mold on leaf and stem.  The condition is commonly referred to as Powdery Mildew and is the result of a fungus growing on the surface of the plant.  Powdery Mildew is an affliction shared by many species of plants, but for most plant species, there is a specific fungus that produces the condition.  Spores produced by the fungus on the Japanese Honeysuckle will only grow if they happen to land on another honeysuckle vine. 

Powdery Mildew definitely weakens the plant and it can cause death in severe cases.  Shade, humidity and temperature are the three factors affecting the growth of the fungus.  Spores ride the wind and blanket the countryside.  I’m certain that all honeysuckle has been in contact with the spores.  When conditions are favorable, the fungus thrives and the plants suffer. 

The fungus is only present in a few small patches of Japanese Honeysuckle at Blue Jay Barrens. The plants probably won’t die, but I’m hoping to see a significant reduction in competition between honeysuckle and the desired native plants.  Powdery Mildew has long been known to people who cultivate Japanese Honeysuckle.  Those people are happy to share methods of saving the plants, but I haven’t found any who have recommendations on how to encourage the fungus.

I’ll be keeping a close eye on this honeysuckle area as the summer progresses.  I would love to discover a method of growing the fungus on all of the Blue Jay Barrens honeysuckle.  Since the fungus growth is more a function of weather conditions, there’s no way that I can control its spread.  About the best I can hope for is the elimination of honeysuckle in these small areas.  I’ll certainly keep hoping for the best.

Fence Row Clearing - The Final Push

I’m getting near the end of my fence row clearing project.  I’ve moved into an area about 100 feet long that is a tangle of fallen trees, rough ground, Multiflora Rose bushes and Japanese Honeysuckle vines.  As I worked my way to this point, I was hoping that I would discover a way to make this job a little bit easier.  Unfortunately, I was struck by no such brilliance.

The number of rose bushes was not great, but the density of canes was daunting.  Vertical canes rose 25 feet into the trees and 20 foot horizontal canes wove together with neighboring bushes to form an almost solid mass.  The whole arrangement was like one of those ecosystem web diagrams.  Pulling on a single cane caused the whole thicket to respond.  I think I got snagged by rose thorns every time I moved.

There was no way to get the mower in there, so I waded in with Big Loppers and started taking out one bush at a time.  Each extraction was a tug of war with the Japanese Honeysuckle.  After pulling a few bushes free, I would take JR in to cut the honeysuckle down close to the ground.

I take a lot of before and after photos, but those don’t always convey the degree of difficulty experienced in getting from one condition to the other.  I think I was constantly tangled in rose canes the entire time I spent working in this one small area.  If I’d lost any more blood to rose scratches, it probably would have been necessary to stop for a transfusion.

Several pounds of mulched honeysuckle vines were left on the ground.  In order to have a chance at eliminating the Japanese Honeysuckle, I’ve got to get it out of the trees and on to the ground.  By spraying glyphosate herbicide in late fall when just about everything except the honeysuckle is dormant, I’ve been able to completely eliminate Japanese Honeysuckle and leave the native plants.  So far, I’ve only done this on small plots.  In the next year or so I’ll begin to try it out on larger areas.

In a few places, I cut the honeysuckle off at the ground, but couldn’t get the vines to come out of the tree.  After the vines dry, they’ll more easily come loose.  If I can’t get them down in the next couple of weeks, I’ll cut them off as high as I can reach. That way I’ll be able to see any invasives growing up around the base of the trees when I go out to spray sprouts this spring.

This fence row segment now opens into last year’s Multiflora Rose control area.  I think I’m going to be happy with the results of this project.

Oak vs Honeysuckle

After removing an Autumn Olive shrub and its attending Japanese Honeysuckle, I found a nice young Shingle Oak struggling with its own honeysuckle infestation.  Growing conditions definitely improved for the oak when the Autumn Olive came down.  Now it needs freedom from the honeysuckle.

Japanese Honeysuckle is a perennial vine that uses woody plants as support for its vertical growth.  The spiraling growth habit allows it to climb even a limbless tree trunk.  The vine will climb into the treetop and exploit this position in the sun by extending its leafy twigs above the oak leaves.

The Japanese Honeysuckle Vine bears no aerial roots, so the plant must maintain its connection to the soil.  Multiple vines are usually found at the base of any affected tree.

Vines travel along the ground until they reach a vertical structure.  At each node along the vine, roots penetrate the soil and additional vines are produced.  In this way the vines can effectively carpet the ground and all surrounding vegetation.  The end result is a solid stand of Japanese Honeysuckle.

Both the supporting tree and the entwining vine continue to increase their size.  The vine becomes an unyielding collar around which the tree spreads as it grows.  The entrapped vine physically weakens the trunk and cuts off the movement of plant nutrients.  Eventually the tree top, too weakened to support the mass of vines, will fall.

I removed the vines from the tree, but the tree may not be able to heal itself.  This could easily develop into a weak place that will break later in the tree’s life.

The tree is now honeysuckle free.  I’ll monitor its progress to see how it reacts to its newfound freedom.  If the top looks like it’s beginning to fail, I may cut the tree off at the ground and let it regrow.  Oaks are very good about producing healthy stump sprouts and in a good location could easily be back up to 12 or 15 feet in just a few years.  That may be a better long term option for this tree.

Japanese Honeysuckle

It’s a shame that some invasive exotic plant species have to be so attractive. These Japanese Honeysuckle fruits almost sparkle in the sunlight. The glossy skin easily reflects the silhouette of the photographer’s head. The honeysuckle would be a joy to see, if it was a native plant. As it is, I’m just aggravated by the showy display.

Japanese Honeysuckle seems to be a replacement plant for other invasives. As I remove Multiflora Rose, Autumn Olive and Bush Honeysuckle, the Japanese Honeysuckle jumps up and takes over that space. The bushier invasives seem to out compete the Japanese Honeysuckle vines. Once the bushes are gone, the spindly vines are free to grow with abandon. If a fruit eating bird eats from one type of woody invasive, it seems to eat from them all, so it makes sense that the seeds from all of these invasives would be dropped in the same general area frequented by the birds.

The key to slowing the influx of invasives onto a site is to eliminate the berry producing individuals. If no fruit is being produced, there is no reason for the fruit eating birds to concentrate in that area. Most of the bird flocks feeding on the invasive fruits seem to concentrate on a single type of fruit until it’s gone. I’ve watched huge flocks of Starlings or Robins come through an area and feed on Bush Honeysuckle that was growing alongside fruit laden Eastern Red Cedars. All honeysuckle berries were consumed, but the cedar fruits were left untouched. Weeks later, the same flocks came through feeding on cedar fruits. My goal is to eliminate fruit production by invasive species and the Japanese Honeysuckle is my next target. If the birds are feeding on native fruit, they will be dropping native seeds. I know that eliminating fruit production won’t stop the influx of invasive species, but I believe it will significantly reduce the amount of new seed coming onto the property.

Japanese Honeysuckle vines growing along the ground don’t seem to produce fruit. It’s not until they ascend some type of structure that you see flowers developing. My first priority will be to cut back all climbing vines and eliminate fruit production. With luck, this will be my last opportunity to photograph Japanese Honeysuckle fruits.

Once I’ve beaten the honeysuckle back to the ground, I can work on ways to kill it completely. Mowing the vines every couple of years keeps them under control, but it doesn’t stress the plants enough to kill them. If I have to live with Japanese Honeysuckle, I’d rather it was in this form than draped over the trees and fences.

Rose Control Success

I always enjoy those rare occasions when events proceed along a course as anticipated in my carefully designed plans. Twelve months ago, this scene existed only in my mind. The 2010 vista was one of massed Multiflora Rose canes and bright clusters of rose fruits. I knew that my efforts to cut and spray would result in fewer roses on this site, but I never thought it could look so rose-free after just one year.

It’s wonderful to just stand and look at this roseless site. I can now get an idea of the potential of this area for developing into a diverse native mix. There are primarily grassland and open field components expressing themselves, so I’ll probably manage in that direction. That will mean the removal of a few small trees.

The Multiflora Rose threat may have been abated, but there’s still work to be done to control some other invasive plant species. Japanese Honeysuckle has certainly taken advantage of the loss of rose competition. I’m still developing my Japanese Honeysuckle control methods. I’ve had some excellent success in spraying honeysuckle with glyphosate herbicide in late fall after most other plants have gone dormant. The problem occurs when trying to control the honeysuckle in situations where desirable plant species maintain green foliage through the winter.

Fertile leaves of the Sensitive Fern indicate a strong presence of that plant. I always enjoy seeing these ferns and wouldn’t mind a mass of them here.

In all of my searching, I only found two small living rose plants. I cut hundreds of plants from this site last year. They were so numerous and closely packed together that I couldn’t mark each individual bush. I think it’s amazing that I did such a good job of finding and spraying the sprouts this spring. I’ll mow this area again during the winter to make sure I’ve found all of the roses that need treatment. Mowing will also knock back the Japanese Honeysuckle.

There are no rose sprouts to be found in the more shaded portion of the rose control area. The vegetation isn’t yet thick enough to hide the rose plants, so I won’t mow this when I do the rest. There are more trees growing here and there seems to be a potential for some quality deciduous forest to develop. Except for the need of some minor Japanese Honeysuckle removal, this area can be left to maintain itself for a few years.

Basal rosettes of Golden Ragwort are now the most numerous species growing in the shady area. There were some small patches of the yellow flowers present this spring, but I think this will develop into a solid mass of blooms next spring. I hope I can have at least one of this winter’s projects be as successful as this rose control effort.

Middle Field

I call this the middle field, not because it’s in the middle of the property, but because it sits in the middle between the two other recently cropped fields at Blue Jay Barrens. This is also a field of acid soils sitting on shale bedrock. The bulk of the field is a mix of short grasses with many short growing forbs.

Portions of the field were so badly eroded that vegetation still has a problem growing. It’s common to find Reindeer Lichen filling in the voids between the plants.

This is my only low pH field with a short grass component, so I’m always looking for something unusual to show itself here. There’s not a lot of management necessary in this part of the field. If I do anything, it will be to remove a few of the larger cedars.

The field is rather tear drop shaped and as you approach the narrow end, tall grass becomes dominant. Indiangrass is the most common species. Indiangrass readily colonizes new areas and can take over a small area in five to ten years.

This upland edge used to be thick with Multiflora Rose and Autumn Olive. Several years of clearing and herbicide applications have cleaned up that problem and allowed native species to move in. I’m still dealing with many new Rose and Autumn Olive seedlings, but this problem will improve each year.

The next task is to remove the profusion of Japanese Honeysuckle. A couple years of mowing will reduce the amount of honeysuckle, but I’ll eventually need to spray. Honeysuckle stays green into early winter, so it is easy to eradicate by spraying glyphosate in late November when everything else is dormant and immune to the spray.

The problem is that not everything on this site is dormant during the winter. This is Cut-leaved Grape Fern, Botrychium dissectum. These Grape Ferns can be found growing in most parts of the field, but they are particularly abundant beneath the honeysuckle vines. They are short enough to be unharmed by the mower, but even the thickest honeysuckle canopy can’t protect them from the spray. I’m still debating what action to take in dealing with the honeysuckle in situations like this.

Cut-leaved Grape Fern has quite a variable leaf pattern. These deeply dissected leaves are typical of the species, but are the least common leaf form at Blue Jay Barrens. The leaf form I typically find is minimally dissected and sometimes exhibits an almost entire leaf margin. I once thought I had many different species of grape ferns until I discovered what was going on.

There are also several small Blackjack Oaks that I will let remain. This oak seems to have more interactions with prairie invertebrates than any other oak species.

There are Allegheny Mound Ants in the shale based soils, but the mounds are not as numerous here as in the limestone soils. This mound was wreathed by a thick growth of Wild Sensitive Plant.

I don’t know what phenomenon caused the plants to be so thick here. Wild Sensitive Plants have the nectar producing gland at the base of the leaf petiole, but I’ve never seen the large Mound Ants visiting this feature. Perhaps the ants tried to keep the plants cleared from around the mound, but couldn’t keep pace with these rapid growing annuals. I guess this is just one more thing to watch and wonder about.

Invasive Species Control

Removing invasive plants can sometimes just give you a better view of the invasive plants growing behind. When I removed the rose thicket over the winter, I stopped clearing at the grown up fence row. The fence row will get cleared after I’ve searched through and removed the old wire and other items that seem to accumulate along fence rows. With the thicket removed, I get a much better look at what I’ll eventually be dealing with.

Of course, there are a few rose bushes in there. The attractive flowers and heavy fragrance do nothing to keep me from wanting them all gone. I know that there will always be some Multiflora Roses growing at Blue Jay Barrens. New seeds are constantly being brought in and small sprouts keep enlarging into bush size.

It’s not my goal to eliminate the roses. That would be an impossible goal. I’m only trying to control them. By control, I mean to keep the effects of their intrusion to a minimum. When I can walk around Blue Jay Barrens at this time of year and not see any blooming roses, I’ll have reached the control goal. I’m very close to that point now.

While I’m busy getting rid of roses, other invasive plants are trying to take hold. Japanese Honeysuckle has taken advantage of the shield of rose bushes to climb high into the trees. When I work on Japanese Honeysuckle control, my first goal is to get it out of the trees. It’s hard to deal with something you can’t reach, so I want to get it all down to my level.

Honeysuckle flowers combine with those of Multiflora Rose to fill the air with sweetness. Some people cherish the fragrance. That means I sometimes have to be somewhat secretive when controlling these plants, especially near the road where I can be seen.

Japanese Honeysuckle is a rapidly growing vine that sprawls across the ground as well as climbs any vertical structure. It’s most effective means of killing competing vegetation is to block the sunlight from plants beneath it. The leaves form a thick mat with their upper surface facing the sun. In doing this they create a screen that blocks the light as effectively as a blackout curtain.

Woody vegetation is often killed when girdled by the vines and the weight of the massed vines can bring a tree to the ground. I look forward to the day when I’ll have to leave Blue Jay Barrens in order to see Japanese Honeysuckle or Multiflora Rose flowers.