Mile-A-Minute AKA Polygonum perfoliatum or Persicaria perfoliate

Over the last several years I have seen Mile-a-Minute vine growing in several areas around Scotland and its adjacent towns.  The plant is native to India and East Asia where It is used medicinally.  Mile-a- Minute is an annual vine, one that dies back at the end of every growing season.  New plants emerge the following year, germinating from seeds that were produced by the plant the year prior. You might wonder how an annual plant that dies back completely every year can be invasive.  As its common name Mile-a-Minute suggests, the vine with its unusual triangular leaves and clusters of pretty blue seed filled berries, grows very rapidly up to 6 inches a day and up to a total of 20 to 30 feet in its one growing season! The pendulous clusters of berries drop off very easily when the vine is disturbed.  Mile-a-minute vine has tiny barb like thorns aong h stem which help it to climb adjacent trees and vegetation.  The seed containing berries fall from the vines which have climbed high up into the trees and shrubs.  They end up being widely distributed below eventually germinating and creating more plants the following year.  Some of the seeds are also consumed by birds and animals.  After passing through their digestive tracts the still viable seeds are dropped by them on their travels, thus allowing the plant to germinate and colonize in an entirely new area.  Mile-a-minute prefers to grow on wet soil in sunny locations.  It can grow along stream banks or wetlands where seed can be carried by water. 

I saw this plant for the first time many years ago when following a trail of mysterious flag like markers leading through the forest to the banks of the Shetucket River.  There it was an unusual and very distinctive looking plant that I had never seen before.  After a little sleuthing, I discovered UCONN Agriculture was doing an experiment introducing a host specific insect (a little more on that later).  More recently I noticed Mile-A-Minute growing along the roadside on Jerusalem Road in Windham, and even more recently along a roadside adjacent to a wetland here in Scotland.  Since then, I have seen it distributed in several other areas throughout our town.  Even during the winter, this is an easy plant to spot, as the remains of the vine leave a brown net like blanket over every tree and shrub covered during its summer growth.  I tried pulling some of the vine out the summer I first noticed it growing on Station Rd.  By the time I saw it, it was a little too late in the season as the vine had already developed sharp barbs and plentiful berries. The berries just tumbled off in profusion as I uprooted and pulled the vine from its supports.  Never-the-less I filled several large garbage bags before I found the vine had woven itself through a thorny multiflora rose.  It was at that point I was forced to surrender.  There is no question, an attempt to remove invasive plans can at times feel overwhelming. 

HOW TO REMOVE

For small populations of this annual plant hand pulling during its early growth is recommended.  The barbs become stiffer as the plant matures so it is easier and less physically painful to pull young plants.  Gloves will help, and it should go without saying that it is best, if possible, to pull plants before berry/seed formation.  Even immature seeds have the potential to germinate.  If infestations are larger, mowing is considered a good option.  It is best done regularly so that the plant does not get a chance to develop seeds.  If you will be  mowing, be certain to check the mower and blades afterward.  You do not want to inadvertently move seeds or plant parts to another location and start a new infestation. Another option is using a string trimmer to cut the plants to ground level.  In larger infestations preemergence herbicides can be effective.  There are a couple that are recommended, and timing of application is crucial for them to be effective.  Application instructions are a little lengthy, so I will direct you here for more information http://extension.psu.edu/mile-a-minute.com. 

Biologic Control

Back to those mysterious flag-like markers. I found that UCONN had been conducting an experiment along the banks of the Shetucket River with a host specific weevil called Rhinoncomimus latipes.  It was found that the weevil will not eliminate Mile-A-Minute, but it does weaken the plant by consuming its leaves therefore helping to stunt the plant's growth.  Interestingly the colonies of this plant that I located recently all exhibited holes in their leaves, signs that the weevil was in fact munching on the plant.  On its own, the weevil had traveled from the Shetucket River and infested all of the other colonies of Mile-a-minute plant that I discovered, so this insect is having an impact.  If you spot large colonies of this plant that are not yet hosting the weevil, it is perfectly fine to transport portions of a plant that are infested to the new area. The best long-term solution is to suppress the growth of this vine long enough for other native plants and especially trees to gain footing.  Once that happens, it should help to eliminate the sunny area mile-a-minute requires to thrive.

 

                                 Black Swallow-wort in bloom

                              Black Swallow-wort with seed pods

                 Black Swallow-wort AKA Vincetoxicum Nigrum

If you ever felt like a meadow sprite tied your feet together while walking through a field, you likely encountered black swallow-wort.  It is native to various parts of Europe.  The swallow-wort family of plants was once used medicinally as the suffix "wort" in any plant's common name suggests. Black swallow-wort was first imported to the U.S. as an ornamental in Ipswich, Massachusetts in 1854.  In my opinion the plant's beauty is questionable.  After only ten years in the Ipswich area black swallow-wort was identified as a garden escape.  It had already begun to naturalize in the area.  Since then, it has spread prolifically throughout New England and far beyond.  Today it is considered an invasive plant in states as distant from New England as Wisconsin and California.  

Black swallow-wort is a vine that quickly grows into a 3-9-foot-long tangling mass climbing tall grasses and shrubs.  The shiny leaves are oval with pointed tips.  During the summer, the plant bears clusters of tiny dark purple flowers.  As I am writing this it is mid-June, and the flowers are presently in bloom.  The entire plant gives off an unpleasant off-putting odor difficult to describe.  Once you are familiar with the scent though, you will be able to detect a large infestation of this plant during the intense summer heat using only your sense of smell. After the tiny flowers are pollinated, the plant forms long slender pods containing a great multitude of seeds each with fluffy hairs attached.  When the pods burst open these silky hairs act like parachutes, helping to disperse the seeds over long distances. If the seed pod description sounds familiar to milkweed, that is because this plant is a relative.  That unfortunate familial connection encourages the monarch butterfly to lay its eggs on black swallow-wort which they mistake for their preferred native milkweeds.  When the Monarch caterpillars hatch, they are unable to consume the black swallow-wort foliage, so they perish. Left unchecked, and being yet another invasive plant with allelopathic properties, black swallow-wort is capable of invading an entire field.  It crowds out native species such as goldenrod, native milkweeds, asters, etc.  Neither deer, or any of our other native wildlife will forage it, and presently there are no insects that consume it. In addition, it is a plant poisonous to domestic livestock. This plant has absolutely no native predators to keep it in check.  It is for that reason controlling its spread becomes our job!  

HOW TO REMOVE

Removal methods depend upon the scope of the problem.  If you are fortunate enough that only a few plants are present, you can dig them out being very careful to remove the entire root system.  Unfortunately, new plants will form from any remaining root segments left behind.  Trying to pull the plant out without first digging will cause the body of the plant to separate from the roots and regrowth from root segments left behind will readily occur.  

Fortunately, most livestock will not consume this plant if it is growing in their pasture.  Because of that, in a limited pasture setting, black swallow-wort will grow taller than the other forage material, making it easy to spot.  If it is found growing in a lawn or pasture, the plant can be mowed. Repeated mowing will not kill it, but mowing will keep black swallow-wort from forming flowers and resultant seed pods therefore preventing the plant's spread from seed. If you are using mowing as a deterrent be sure to mow during mid to late summer to cut back any seed pods that may have begun to form.   

If you are comfortable using an herbicide, a foliar spray using a diluted triclopyr solution, following instructions the product's label, is the recommended method for this plant's eradication.  Triclopyr is a broad leaf specific herbicide, so it will not harm adjacent grasses.  That means it is perfect for a lawn or pasture. The herbicide should be applied twice during the plant's growth cycle.  First in June and again in August after the seed pods have developed. In my opinion black swallow-wort is among the most difficult invasive plants to eradicate.  Unfortunately, in the section of Scotland where I live the fields have become inundated with this invasive plant, and if it is not kept at bay, I fear it will overtake the entire Waldo valley!  

A potential ray of hope is a biological control method first introduced in 2018. The larvae of a moth called Hypena opulenta, was found munching on black swallow-wort in Ukraine.  The moth was introduced in several carefully monitored areas including some in Connecticut.  The moth's larvae greedily consume the mature leaves of the black swallow-wort plant.  UCONN Extension is one of the institutions experimenting with this biological control method, and these moths have been released as near as Stonington, Connecticut.  Unfortunately, biological control using Hypena opulenta moths is still in its experimental stages. The moths are not yet available to the public. As you can imagine, biological control of invasive plants brings potential risks. The introduction of a new foreign species is not entirely predictable.  In this case as with others, if the biological control is deemed safe and effective, it could help to keep the use of foliar herbicides to a minimum, proving to be the lesser of two weevils.  To date the black swallow-wort plants in the meadows all around me, here in the Waldo valley, are all lush and healthy and growing with great gusto.  I have not observed a single hole in any of their leaves.  The Hypena opulenta moths and their larvae have not yet arrived in Scotland.  I am keeping my fingers crossed that they will arrive soon.

 

                      Tree of Heaven AKA Ailanthus altissima

                                  Ailanthus altissima With Flowers

                                    Ailanthus altissima With Seeds

I have yet to encounter this tree firsthand in our town, but I am told it is in fact growing here, and that is a serious issue.  Tree of Heaven is native to China where it has many uses in traditional Chinese medicine.  It is also a host there for a particular moth whose cocoons are used to produce silk.  The tree was first introduced to Europe in 1740 during a time when there was a great interest in Chinoiserie, a fancy word for Chinese influenced decoration. There it gained a positive reputation as a fast-growing shade tree. It was eventually marketed here in the U.S. as such.  Tree of Heaven was introduced to the United States in Philadelphia in 1784. Nobody was yet aware of the consequences, but over time its rapid uncontained spread throughout the United States has made it an invasive species.  It is considered invasive in Europe as well.  The tree got both the last part of its Latin name altissima which translates to very high, and its common name for its rapid upward growth, as though it were reaching for the Heavens.  I mean holy moly, this tree can grow up to eight feet in just one year, and it reaches a mature height of eighty to one hundred feet!  

                                               Staghorn Sumac

                                               Black Walnut Tree

In appearance, the tree strongly resembles several native trees including staghorn sumac, and black walnut trees.  Be cautious so as not to jump to conclusions and eliminate the wrong tree.  You may just be spotting an innocent bystander.  There are various methods that you can use to discern which tree you are dealing with.  There are differences in bark texture, flower structure and subtle variations in leaf structure, but a quick and definitive method of positive identification of tree of heaven is to rub a leaf between your fingers.  If the crushed leaf has a very unpleasant odor resembling rotten peanut butter with a little skunk odor thrown in, it is the invasive Tree of Heaven.  Mid-summer around July, if you are nearby when these trees are in bloom, you might also smell their strange perfume wafting through the air. The male trees produce abundant flowers that carry that unpleasant aroma which, believe it or not, attracts pollinators.  Not all pollinators are attracted to what we consider sweet fragrances!  The female trees of course also produce flowers although they are fewer in number.  As the growing season progresses, the female trees produce prolific dangling bunches of reddish-brown seeds.  To me at least, this is when the tree is most easily recognized.  The seeds ripen in September and fall gradually from the tree throughout the following months.  Each seed in the cluster is encased in a winged seedpod called a samara, similar to a maple tree seed.  These "wings" allow the seeds to travel great distances.  

The thing is, even without the seeds this tree has the capacity to reproduce.  Its roots travel horizontally, as far as 50 feet, creating new shoots that sprout into more trees. In this way Tree of Heaven can rapidly form colonies.  I often see large colonies of Tree of Heaven growing alongside various highways. Like some other plants that are now considered invasive, Tree of Heaven has allelopathic powers.  Portions of the tree create chemicals that are toxic to other plants.  These compounds suppress the growth of native plants encouraging the creation of a monoculture.  As you have likely heard in the news over the last few years, this tree is the host to vast numbers of the rapid breeding sap sucking Spotted Lantern Fly. This pest is an agricultural nightmare.  It is now found feeding on a variety of plants and trees.  With its capacity of killing them, it is especially harmful to both native and cultivated grapevines. Because Tree of Heaven is the Spotted Lantern Fly's natural host tree, and especially because of the Tree of Heaven's aggressive growth habits, this invasive tree is best removed as soon as possible after its discovery on town or private property.

HOW TO REMOVE - Read to the end!  Exciting news!!

Even young trees have a long tap root, making it difficult to hand pull them unless they are mere seedlings. If you are hand pulling young seedlings, be certain to remove the entire taproot as the plant can resprout from even a tiny fragment left behind.  The recommended method of removal of larger tree specimens without herbicide use is to cut the tree as low to the ground as possible.  Unfortunately, this will encourage sprouts to form, and they too must be cut as they appear.  It may take years of monitoring, cutting back emerging sprouts twice a year, but continued cutting of new sprouts should eventually deplete the strength of the root system and eliminate the plant.  

If you are comfortable using herbicides, the herbicide of choice for this tree is Triclopyr.  Over the course of time, different methods have been recommended.  Presently, the most effective method of killing a large tree without encouraging sprouting from the root is to make downward hatchet strokes in a perforated pattern around the trunk of the tree into the cambium layer. The cambium layer is the portion between the bark and the central portion of the tree.  It is the part of the tree that channels nutrients to the crown of the tree, and back to the root.  Apply a concentrated solution of Triclopyr in the pockets you created around the tree.  You may need a second application after several months.  Over time this will gradually weaken and kill the tree.  Another method involving herbicides still being used, especially if the tree is tall and in a dangerous place where you need to control its fall, is to cut the tree as low to the ground as possible and paint the stump with a concentrated solution of Triclopyr.  Painting the stump helps to prevent the stump from resprouting.  The root system will send up sprouts as a reaction to the tree being cut down, and you will have to address the resultant sprouts by using a spray in 8% strength of Triclopyr.  The foliar spray should be applied after the leaves of the sprouts have fully matured. 

Possible future biological control - Samia Cynthia AKA Ailanthus silk moth, native to China, is a pretty moth with crescent decoration on its large wingspan.  This moth lays its eggs solely on the Tree of heaven.  The moth's larvae when hatched, can quickly consume a vast amount of foliage from this tree though they will consume other foliage as well.  The moth's distribution in Connecticut is fairly spotty at this time.  I imagine their population will increase along with Ailanthus altissima as time progresses.  Hopefully that will be a good thing!

The really exciting part! - I recently found exciting information about a fungus I wanted to share, because who wouldn't be excited about a fungus right?  This one, first recognized as a potential slayer of Ailanthus altissima in 2024, seems to have originated in the soil in Pennsylvania and Ohio. It's called Verticillium nonalfalfae. It causes Ailanthus wilt which, exactly as it sounds, first presents as wilting foliage, and then as a yellow brown discoloration of the wood directly below the bark. The fungus rapidly causes death to the tree. The fungal disease passes easily from root to root contact so a single application can eradicate an entire colony of Ailanthus Altissima. In addition, the fungus can be moved from infected trees to healthy trees simply by moving an infected portion of root into contact with healthy roots.  There does not appear to be any significant negative effect to native vegetation, although this fungal disease does negatively affect the hops plant. Use of Verticillium nonalfalfae as what is essentially a natural herbicide active against tree of heaven is presently in the research stage and not yet available for public use, but once it is approved, there is hope that repetitive chemical herbicide application to eradicate tree of heaven will no longer be necessary.

 

Multiflora rose

Native rose example

Multiflora Rose AKA Rosa multiflora

Multiflora rose was first brought to the east coast of the United States from Eastern Asia in 1866.  Because its rootstalk has such a hardy nature, other more delicate roses were grafted to it.  During the 1930's multiflora roses were used for erosion control.  Farmers also used this plant to create a living fence to contain livestock.  The plant readily escaped cultivation and today multiflora rose is found in fields, along highways and forest edges and just about everywhere that is not regularly maintained. It can climb to incredible heights seeking sunshine.  Shortly after moving here, I had a lengthy and painful encounter with it.  During the process of restoring a garden that had been abandoned for several years, I had the task of removing plants that had climbed and engulfed a rather tall tree. Obviously, I lived to tell the tale, but during the process it felt like I was wrestling a mad tiger, and I'm glad it's over!  

The many branches of the plant are covered in single or pairs of recurving thorns that very much resemble a cat's claws. They help the plant to climb, and also act as a defense mechanism, causing many potential multiflora rose gourmandizers to avoid munching on this plant's foliage. The fruits which are called rose hips and are produced in great numbers after the flowers fade, are another matter though. They are nutritious and appealing to a variety of birds, and small mammals and are readily consumed by them. During their travels, the seeds contained within the hips are carried great distances and dispersed randomly after passing through their carrier's digestive tracts.  It is possible for multiflora rose seeds to remain viable for up to 20 years.  As if that is not enough, this plant has an additional method of propagation. When the long branches fall to the ground, they frequently take root forming additional plants. In botanical lingo, this is called vegetative propagation. 

It is interesting to note that rose hips gathered in winter from many types of roses including multiflora, as well summer gathered petals and leaves are nutritious for humans too.  The hips especially are high in vitamin C. Should you be interested in that aspect, here is a link for your exploration https://eattheplanet.org/multiflora-rose-an-invasive-but-nutritious-wild-edible/ For more information and for pictures of the six indigenous roses found in Connecticut a very interesting website can be found here https://www.conngardener.com/wild-about-native-roses/ .

It is during this time of year, June when the numerous white flowers of multiflora rose are in bloom that their intoxicating fragrance is carried in the air to the point that you can almost drink it in.  In June I almost hate to see multiflora rose eliminated. Unfortunately, the plant has crowded out many of our native species.  For this reason, it has joined the outlaw plant list. Hopefully when multiflora rose is removed, or at least contained, our fragrant native roses with their single pink blossoms and equally nutritious hips and leaves will again regain a foothold in our landscape.

HOW TO REMOVE

If you happen to have a herd of goats, or can borrow some, you are in luck!  This is one invasive plant that goats readily consume, and they are not at all deterred by the thorns.  If you don't have access to goats, it is time to take matters into your own hands.  Suit up properly.  Get some heavy weight gloves and loping shears.  I would also suggest eye protection. Remove the branches with loping shears as you can reach them and leave them in a sunny spot to dry out. They can then be burned or brought to the landfill.  The remaining stump and root system can then be dug out, or you can apply a concentrated herbicide to the freshly cut surface of the stump to prevent re-growth.  After removal, you will need to monitor the area for several years to check for new emerging plants that may germinate from seeds left behind.  The smaller plants are fairly easy to pull out with a gloved hand. 

Very large infestations of multiflora rose will likely require a broad-spectrum herbicide such as dicamba, glyphosate or triclopyr.  The diluted herbicide needs to be applied when the plant is fully leafed out so that it is carried to the plant's roots.  Dicamba or triclopyr herbicides will not kill surrounding grass, whereas Glyphosate will.  Applying herbicides should be a last resort, but at times it is the only practical choice.  If you are comfortable using an herbicide, after reading the instructions, mix it to the appropriate strength and make the application on a calm day.  That helps prevent overspray making it easier to target only the plants you want to eliminate.  When using herbicide always wear protective clothing, gloves and a face shield.  Be sure to follow instructions on the label.