How to kill bittersweet?

TAKE BACK CONTROL OF YOUR YARD! How To Eliminate Invasive Oriental Bittersweet

YARD OVERRUN WITH Oriental Bittersweet_ How To Control This Destructive Vine

Aggressive Invasive Oriental Bittersweet How To Remove Oriental Bittersweet From Your Yard

Battling ORIENTAL BITTERSWEET How To Control Invasive Bittersweet

Control oriental bittersweet vine in your yard before it takes over. Beautiful Fall blooms yet so destructive.

Today, I am going to discuss a problem many homeowners face. When Oriental Bittersweet vines are left unrestrained, they consume your entire yard. Oriental Bittersweet vines make beautiful Fall wreaths. The attractive yellow red cluster blooms appear in the early Fall. Although the blooms are attractive, they contain the seeds that produce the vines. The seeds grow into aggressive, invasive vines that are destructive.

How to Get Rid of Oriental Bittersweet & Take Back Control of Your Yard

What is Oriental Bittersweet?

The scientific name of Oriental Bittersweet Vine is Celastrus orbiculatus Thunb. Also known by many common names. Oriental bittersweet, Asiatic bittersweet, Asian bittersweet, Round-leaved bittersweet. Climbing spindle berry and Oriental staff vine.

How to Get Rid of Oriental Bittersweet Take Back Control of Your Yard – Bittersweet Vines Climbing Surrounding Shrubs

Oriental Bittersweet Origin

The oriental variety is an Eastern Asian native vine (Fryer 2011). Native to China, Japan, and Korea. Introduced in the US in the 1860s. Originally used as an ornamental vine and for erosion control purposes. The deciduous woody, vines wrap themselves around plants, shrubs, trees, and anything else it can scale. As the vine grows, it chokes plants, shrubs, and trees. Weight of the vine can bring down entire trees over time. A rapidly spreading vine can grow 60 and up to 90 feet long.

Oriental Bittersweet Description

If you are unfamiliar with Oriental Bittersweet, we assure you it is destructive. Destructive to the garden, yard, landscape, and home. Oriental bittersweet is an invasive, climbing woody, non-native vine with dense foliage. The vines engulf garden plants and other structures. Vines attach to plants, shrubs, trees, sheds, and fences. As it grows, it wraps itself around what it is climbing.

As a result of this, the vines smother the plant, shrub, or tree that it is attached to. If allowed to grow unrestrained, it can wreak havoc on your entire landscape. Aggressive oriental bittersweet can do considerable damage in a single year alone!

Oriental Bittersweet Size at Maturity

Mature Oriental Bittersweet stems grow up to 4” and more in diameter. It climbs large trees and expands well over 60’ high. Green fruit clusters become yellow or bright orange in late Summer. In early Fall, the membranes split and bright red fruit appears. Each bittersweet fruit holds 1 to 2 seeds. The Bittersweet seeds are spread to the surrounding areas by two methods. Either the seeds drop to the ground once the membranes have split. Or the seeds are carried off by birds. Fruit clusters are striking in appearance. The fruit clusters part of the vine is attractive and in demand during the Fall season. It is frequently used to create Fall wreaths. But beware! The seeds eventually become vines. And take hold of your yard very quickly.

Oriental Bittersweet Roots

How to Get Rid of Oriental Bittersweet & Take Back Control of Your Yard – 3 Small Bittersweet Vines

Oriental Bittersweet is an aggressive, invasive vine. It is prolific and harmful to the surrounding landscape. Oriental bittersweet roots are easily recognized. Roots are orange in color. And have an appearance of intestine-like growth pattern. We have extracted long sections of bittersweet roots 4 to 6 feet long that are 2 to 3 inches in diameter. Bittersweet roots resemble a section of human intestines although orange in color. Yuck!

How Do You Control Oriental Bittersweet?

There are two approaches to controlling Oriental Bittersweet vines. Either manually extract the bittersweet vines and roots. Or use a chemical to eradicate the vines. The manual method can be time consuming and frustrating. Manually removing the vines can make you feel overwhelmed. And even discouraged from continuing the eradication process. However, manually removing the vines is generally more effective. This is especially true with vines above ground.

A chemical method of using a herbicide with Triclopyr is effective but not always immediate. It may take a few weeks to see any improvement. The chemical method must be applied to the root system during the growing season of the Oriental Bittersweet. It is not effective during the dormant winter months when the root system is not growing.

How to Get Rid of Oriental Bittersweet & Take Back Control of Your Yard

Step by Step Process of Controlling Oriental Bittersweet

Oriental Bittersweet vines on our side and backyard were overgrown, mature vines. Bittersweet vines scaled a row of younger, maple trees about 40 feet tall. About a dozen maple trees along the rear property line needed removal due to the vine damage. Damaged Maple trees were in various states of deterioration. A couple of the trees were completely covered by the Bittersweet vines. Others were anywhere from 70 to 80 percent overrun with the vines.

Removal of the Maple trees was necessary. The Bittersweet vines were strangling the maple trees which were either dead or close to dying. Oddly enough, the Bittersweet vines were supporting the strangled trees. Preventing any of the dead maple trees from falling. The entire area trees and vines need to be removed.

These are the steps we took to regain control of our backyard from the oriental bittersweet.

Step 1. Manual approach

First step – to stop the larger heavy vines from growing any further, we cut the vines. The vines with the widest in diameter were the first vines cut. These were the heaviest and oldest of the vines. To cut the widest vines we used a folding Razor tooth pruning saw. Smaller vines (less than 1 inch) were cut with a pair of loppers. Luckily, the vines can easily be cut. The woody vine is not a hardwood but a softer woody vine.

Cut Vines Climbing the Trees

Bittersweet vines were cut so that they remained between 2 to 3 feet tall from the ground. Why cut the vines at that length? Two reasons. First, we wanted to easily locate the vines when we returned to the area. The elimination of the vines using the chemical method was to be completed at a later date. Second, a fresh cut is needed to apply a chemical weed killer. The vine will seal itself once a fresh cut is made. For the best results, the weed killer needs a freshly made cut to be effective.

Control Oriental Bittersweet Above Ground Removal

We removed a few of the entwined Bittersweet vines from the maple trees but didn’t have much luck. The vines were still green at this point. A metal rake, we found works best for removing some of the vines. Since the trees were scheduled to be taken down, we didn’t spend much time removing the vines wrapped around the Maple trees. However, if the trees were to remain it is best left with the entangled branches until they have dried out. Especially when they are so far up above ground level. Attempting to pull entangled vines from a healthy tree is risky. Tree branches can break and cause injury to the tree. Or the vines can snap and whip you as you pull on them.

Allow Vines to Remain in Trees Until They Dry Out

Generally, we allow the vines to remain on the tree until they dry out. The vines that you can reach can be removed with a metal rake. Vines that you are unable to reach will drop to the ground overtime especially during a windstorm. Some of our maple tree branches still have a few old bittersweet vines that were cut down three years ago. As sections of the vine dry out, they eventually fall out of the trees.

Within the next few days, the row of maple trees were taken down by a professional tree removal service team. After the tree removal was complete, we were ready to treat the vine root system. Using the chemical approach below in step 2.

Step 2. The chemical approach

Once the professional tree removal team finished, we returned to the area with vines in the ground. Using our loppers, we made a fresh cut as close to the ground level as possible. Cut the vine as close to the vine root systems as you can. Always wear disposable gloves for protection. Apply an herbicide containing Triclopyr to the fresh cut. Use a disposable foam brush to apply the herbicide. After each cut, immediately brush the exposed bittersweet vine stem with the herbicide. In some instances, roots grew slightly below the ground level in a horizontal manner. To apply the herbicide to those roots, we made a notch on the root then applied the herbicide.

Control Oriental Bittersweet – Effects of the Herbicide

The Bittersweet root system absorbs the herbicide. Herbicide travels and infects the entire root system. Herbicide slowly kills the root system. Bittersweet roots turn completely black when they are dead.

Again, the herbicide is most effective on fresh cuts. Apply herbicide as close to the root system as possible. Herbicide application is applied only during the growing season when the roots are active. Effects of the herbicide is to stunt the root growth. And eventually kill the vine from the inside of the root system. For best results, apply herbicide to the vine root system on a dry day. Then the treated vine should remain dry for a minimum of 24 hours.

Control Oriental Bittersweet – Protect Surrounding Areas

Another consideration is the proximity of other garden plants. Herbicides will damage surrounding plants if accidentally applied to them. We noticed one vine root grew right next to a Maple tree root. The Maple tree was a mature 50 foot tall tree. A tree we did not want to lose. Sometimes it is better to manually extract the roots rather than risk losing other garden plants.

When using herbicides, protect the surrounding areas. Lay a tarp or clear plastic to the garden areas.

Step 3. Root Removal

How to Get Rid of Oriental Bittersweet & Take Back Control of Your Yard – Bittersweet Vine Roots Extracted

After several weeks, we removed the dead bittersweet roots in the ground. Most of the root system should easily be pulled up from the ground. Any part of the root system that couldn’t be pulled up, could be cut out of the ground. We found the vine root system to be quite extensive within our yard. Most of the backyard had several layers of roots growing below the soil surface. So incredibly invasive!

Step 4. Oriental Bittersweet Disposal

We were careful to dispose of the bittersweet vines and root system. Both vines and roots were bagged. And placed with garbage for the landfill. None of the bittersweet made its way to our compost bin. You never want any seeds or partial root systems to take hold of the compost bin.

Terrain Shop, Westport, CT

How to Get Rid of Oriental Bittersweet & Take Back Control of Your Yard – Terrain, Westport, CT

Terrain at Westport, Connecticut. Store display of Oriental Bittersweet Vines at their Westport location. Hmmm. One person’s junk, is another’s treasure?

Oriental Bittersweet – Final Note

So we started this project from a point of feeling overwhelmed. Did we arrive at complete eradication of oriental bittersweet? No, not exactly. My best guess is that we have some level of control of the bittersweet. Probably 80% of the oriental bittersweet above ground has been eliminated. Below ground level, there is quite a bit of the vine root system. Some of the root system might be rotting from within but some appears to be viable.

Next Spring, we’ll have a more accurate idea of how successful we’ve been at controlling the bittersweet vine. One thing we are certain of? There is more work to do in this ongoing battle against the oriental bittersweet vine.

Interested in gardening? If you found this helpful . . .

You May Also Enjoy some of our other gardening related posts.

9 Plants That Repel Bugs Naturally
30 Money Saving Garden Tips for the Frugal Garden
12 Perennials That Butterflies Find Irresistible

And if you have any questions, feel free to reach out to us. We always are ready to help you out. Thank you for dropping by.

Beautiful Easy Organic Gardens

A nice young person from Holyoke, MA writes:
We have an area of bittersweet, brushy growth and trees between our driveway and the neighbors’ home. After we clear the area, our tree removal person says we’ll have to spray continually to retard the bittersweet in order to plant a lawn. What are organic options for this sloped, part-sun site that will help us control regrowth and have an attractive, easy care planting? Thanks! (actually, I’m the organic-gardening daughter wanting my dad not to use Round-up!)
Answer: If you are interested in planting grass, here is what I suggest:
I am not clear about when you plan to get rid of the brush and I am not sure how large this area is, but, if you do the clearing in the spring, you can get rid of the lion’s share of the weed seeds that are there if you are willing to let them germinate and then eradicate them. Don’t plant the new grass seed until Labor Day or after. This way you can allow the weed seed to sprout and then kill them a couple times over the course of the summer. You can kill them by tilling again, spraying them with store-bought white vinegar or pulling them up by hand.
You could also spread sheets of clear plastic over the area and weight them down with stones. The plastic will allow the sun to raise the temperature underneath, (something like a greenhouse) that will kill the plants as they germinate.
Plant the grass on Labor day or anytime in September. Next spring and summer the grass should be growing well. Simple mowing, over time, should keep the brush and weeds under control.
If you are interested in planting shrubs or perennials, you can do the clearing anytime. Then, spread thick sheets of newspaper over the area and cover that with two to four inches of mulch.
Cut holes in the papers or adjust them so you can plant the shrubs or perennials in the bed. If you keep the mulch applied each year, you should be able to keep the weeds at bay.
Larry

by Bruce Wenning

Common Names:
Asiatic bittersweet vine; Oriental bittersweet vine; Chinese bittersweet vine.

Plant Taxonomy:
Family Celastraceae. Genus Celastrus. Species Celastrus orbiculatus Thunb.

Regulations: The importation, distribution, trade, and sale of Asiatic bittersweet vine have been banned in Massachusetts effective January 1, 2009 (Massachusetts Prohibited Plant List website, 2012).

General Description: Asiatic bittersweet is a deciduous vine with alternate, simple, obovate to orbicular (round in shape) leaves with slightly toothed (crenate-serrate) margins (Dirr, 1998). Leaf apex has a slightly pointed tip (Dirr, 1998; Zheng, et al, 2006; Magee and Ahles, 2007). Asiatic bittersweet originates from China, Japan and Korea (Zheng et al, 2006; Huebner, Olson and Smith, 2006).

A 25-year-old bittersweet vine shows the characteristic gray/brown furrowed bark.

This exotic invasive vine effectively utilizes nearby trees, shrubs, or any other above ground structure as scaffolding that helps it to grow upward into sunny exposures using its twining stems. As witnessed on many trees, the growth habit of this vine typically wraps around tree trunks as it grows upwards where it eventually constricts the host plant’s vascular system, thus inhibiting carbohydrate flow from the leaves to the roots and water and nutrient flow from the roots to the leaves and above ground growing points. Eventually, the host plant weakens and slowly dies from a combination of the vine’s rapid shading and vascular (phloem and xylem) constriction; branches die and break off; roots weaken and the host tree may topple over (Fryer, 2011; Ellsworth, 2005). Infested host trees are particularly susceptible to snow, ice and/or wind storms.

If you observe areas that are heavily infested with this vine, you will notice that the growth habit of twining is characteristic of the species and very effective for its survival. In the absence of a structure to climb upon, this vine will use its own twining stems to grow toward the light creating impenetrable thickets in open fields and other areas where there is no other available scaffolding. I have seen this species send up multiple stems that wrap around each other to gain enough rigidity to span into areas too distant for a single vine. Eventually, the wrapped stems contact a very distant branch or tree.

Orange roots are a distinguishing characteristic of Asiatic bittersweet.

The orange-colored roots serve as a diagnostic identification characteristic observed when one pulls out seedlings as well as adult plants. Young vine stems have warty lenticels on light brown colored bark (Somers, Kramer, Lombard, and Brumback, 2006). Older vines exhibit a gray / brown colored furrowed bark.

Invasive Traits

Asiatic bittersweet vine exhibits the following invasive traits:

(1) High seed production and good seed viability. Reproductively mature vines are prolific seed producers primarily in sunny areas. Seed has a high viability to germinate, particularly in the first year of production (Fryer, 2011; Ellsworth, 2005). Ellsworth (2005) stated that from his research and experience approximately two-thirds of first year seed that contacts soil actually germinates the year it is shed when environmental conditions are right. Seed viability drops considerably in the second year (Ellsworth, 2005; Fryer, 2011). Seeds that become part of the soil seed bank show a reduction in viability after the first year; seed bank longevity for this species is short-lived in most soil and site conditions (Ellsworth, 2005; Fryer, 2011). According to Fryer (2011), some land managers have noticed that small portions of viable seed germinated in seed banks older than one year. Seeds are a deep red-purple color embedded in red-colored arils (i.e. fleshy seed tissue) surrounded by orange and yellow capsules (Somers et al, 2006; Dirr, 1998).

Bittersweet uses other plants as scaffolding and is a prolific seed producer.

(2) Vectors. Seed is dispersed by birds and other berry-feeding animals, sometimes over great distances; wind and water are less effective at dispersing seed. The combination of this species’ seed production and viability with the continuous spread by birds makes this vine an effective and efficient invader of residential properties, local landscapes, and larger surrounding ecosystems (Ellsworth, 2005). The vector trait provides an advantage for rapidly colonizing new and especially far away sites.

(3) Sexual reproduction breeding system. Asiatic bittersweet vine is dioecious . Male vines have flowers that produce pollen. Pollen fertilizes a female vine flower that produces fruit and seed. Both male and female plants need to be in close proximity in order to successfully reproduce. Pollination occurs by bees, other insects, and wind. This may help explain why, as an early colonizer, this vine forms randomly distributed and dense populations or patches that appear to “leapfrog” through a woodland (or neighborhood) over time. When left unchecked, these populations can join each other or coalesce forming contiguous populations throughout a property, larger landscape, or region of land overlapping many different types of landforms and/or ecosystems and simultaneously exhibiting different age classes (younger and older vines) growing together. In addition, many ecologists are concerned that Asiatic bittersweet vine hybridizes with the American bittersweet vine (C. scandens), thus diluting the native species gene pool (Dirr, 1998; Somers, et al, 2006).

Side note: Asiatic bittersweet vines that grow as single vines in the woods with no further seed production/germination could be a lone male or female vine deposited by a bird far from the original (dioecious) breeding population, or the vine may be growing under shady conditions. When an opposite sex vine comes in close proximity, the lone vine or new arrival could then produce berries and eventually start a viable, reproducing invasive population (i.e. the leapfrog effect mentioned above) that could add to new populations in the existing area or infest new areas via vectoring birds.

(4) Vegetative or asexual reproduction (i.e. sprouting). Vegetative reproduction occurs when stems are cut or broken. For both male and female vines, sprouting produces more reproductive stems than the original uncut or unbroken stem. Asiatic bittersweet produces new stems from root sprouts as well as from root fragments left behind by incomplete pulling and/or digging (Fryer, 2011; Ellsworth, 2005).

(5) Predator avoidance and/or deterrence. There are virtually no appreciable predators or diseases feeding on this plant to curtail its growth, development, and spread.

(6) The timing of leaf out and leaf loss. Leaves emerge in the spring with other native plants; however, this species holds onto its leaves a little longer in the fall than most native plants. This trait contributes to Asiatic bittersweet’s ability to produce more carbohydrate and other compounds in the leaves by way of photosynthesis and to transport these products to the roots for storage (i.e. cold weather storage for better winter survival and spring growth).

Twining ability and sun/shade tolerance give these 10-year-old bittersweet vines a survival advantage.

(7) Sun/shade tolerance. Asiatic bittersweet is shade tolerant. However, like glossy buckthorn and common buckthorn, it frequently invades sunny areas which is why it is seen growing in open fields; along field, road and, path edges; and in any other areas that are sunny. Ellsworth (2005) stated that Asiatic bittersweet has the genetic variability to tolerate a wide range of sun and shade exposures; high seedling survivorship was observed under deep shade; however, he also noticed that partially shaded conditions contributed to high seedling survivorship.

Ellsworth as cited in Fryer (2011) reported that the thickness of the woodland litter layer affected seedling emergence; seedlings of Asiatic bittersweet were more successful emerging from pine litter layer than thick oak litter. Pine litter has a structure more conducive to air and light penetration than the heavy matting effect that results from overlapping oak leaves.

(8) Time of year of fruiting. Asiatic bittersweet flowers from May to June; flowers are a greenish-yellow color (Zheng, et al, 2006). Flowering time is the same as for common buckthorn. However, the fruiting period is quite long, beginning in July and lasting through October (Zheng, et al, 2006). Like other exotic invasive plants this species has fruiting periods that are longer than most native plants in the landscape which increases its invasion success.

IPM Control Strategies for Asiatic Bittersweet Vine

1. Cultural Controls: Monitor or visually inspect your property for Asiatic bittersweet. Do this at least every June and September. As stated in Part II of IPM Control Strategies for Exotic Invasive Plants, prevention is a cultural control of great value. Do not plant, transplant, or encourage the planting of this species. Do not use this vine in the fruiting stage in holiday decorations particularly Christmas wreaths. Educating others (e.g. clients or neighbors) about the dangers of this pest is another cultural control of enormous value.

2. Mechanical Controls: Pull, dig, and cut. Pull out easy-to-pull plants. If you can’t hand-pull Asiatic bittersweet, then you can dig out the plant. Attempting to pull it out with a Weed Wrench ® can prove to be troublesome for many people because the woody stems have a spongy or soft construct (less rigidity) than other woody plants. Spring or early summer cutting will slow its growth and reduce its ability to form functional male or female flowers for reproduction. Remember, this species is a dioecious plant with male flowers on one plant and female flowers on another plant. Cutting down Asiatic bittersweet vines in close proximity to one another before they flower disrupts an otherwise intact breeding system. In addition, the practice of repeated cutting on a monthly or so basis will be more effective at stunting the plant and inhibiting flower and fruit production.

Asiatic bittersweet twines around itself to create scaffolding, exhancing its ability to spread.

Mechanical controls can be done at any time of the year; however, the best times are the months before or during flowering. Vines that have been cut at the base but are very large or entangled in the host vegetation should be left hanging in place for three to six months before they are pulled down. Freshly cut vines have a spongy or soft construct to their woody stems and need to dry out to become brittle enough to be easily pulled down without damaging host branches.

3. Biological Control: There are no insects, mites or commercially available disease organisms yet found to be effective biological control agents.

4. Chemical Controls: The best time for any control option is just before a plant flowers. In addition, the application of herbicides in July, August, and up to mid-September gives maximum chemical control. These are the months that carbohydrates and other plant compounds are being manufactured in the leaves by way of photosynthesis and transported from the leaves to the roots for storage. This downward flow of plant compounds helps facilitate the transport of foliar and stump applied herbicide to the roots during these months for more effective kill. The mechanical control of cutting or mowing is also very effective during these months for the same reason. For example, when you cut the top off any plant the roots naturally respond by pushing up more top growth (sprouting), reducing the root reserves (carbohydrates and other growth compounds) stressing the plant. Every time you cut the top off you force the plant to sprout which reduces the root reserves and weakens the plant.

Suggested chemical control for vines too difficult to hand pull or dig during July, August, and up to mid-September is to cut Asiatic bittersweet down to one inch from the ground and immediately apply straight glyphosate herbicide to the freshly cut stump using a paint brush or sponge applicator. Roundup ‘poison ivy killer’ works very well. Suggested chemical control in March, April, May, and June is to cut the stump high (six to twelve inches) and let it sprout. Then cut the sprouted plant in July, August, or early September to one inch from the ground and immediately stump-applicate with straight glyphosate herbicide.

A Suggested Asiatic Bittersweet Vine Example Using the IPM Procedure

1. Properly identify Asiatic bittersweet vine. Educate your neighbors and others about what you are doing and why.

2. Hand pull (or cut) what you physically are able before Asiatic bittersweet produces berries (seeds), preferably before September.

3. Using a Weed Wrench® on hard to pull plants is, at times, not practical.

4. Plants that prove to be too difficult to remove by way of pulling or digging you can cut down to a one-inch stump and immediately apply a glyphosate herbicide to the freshly cut stump using a paint brush or sponge applicator. Stump application is very effective during July, August, and up to mid-September. Remember, you may have to leave the remaining vine up into the host vegetation because the vine has to dry out to become brittle enough to be effectively pulled off the host without causing branch damage.

If you cannot stump-applicate the hard to pull plants during the summer months, then you can instead cut the plant six to twelve inches from the ground before it starts to produce berries (seeds) preferably by September (Ellsworth, 2005). After the taller stump has re-sprouted, you cut it to one inch above the ground and immediately apply glyphosate herbicide to the freshly cut stump. Allowing the stump to re-sprout during the summer months draws carbohydrate and other growth compounds from the roots and depletes some of the root energy making herbicide kill more effective.

5. Foliar application of glyphosate works best on multi-stemmed vines that had been repeatedly cut for many years without chemical control follow up or had not been removed by digging. Foliar application works best between July and mid-September particularly on impenetrable thickets growing in open areas such as fields, along road sides and paths where the vines are not growing up on host vegetation. Foliar application transports the herbicide from the leaves to the roots. If Asiatic bittersweet has many stems with foliage and is quite large, it may take one to two years for complete kill after one foliar application because multiple stemmed specimens generally have a very large root system. Climbing vines that have foliage close to the ground should be sprayed from the ground up to six or more feet for effective control. If vines have a small amount of low level foliage and / or are too tall with no available low foliage then stump applied herbicide would be more effective. Individuals contemplating using chemical control of Asiatic bittersweet in or near wetlands must use a wetland approved herbicide. It’s the law.

6. Cold weather stump application (November through February; temperatures ranging from 15.8 to 46.4 Fahrenheit) (Reinartz, 1997) reduces the risk of contaminating non-target plants. University of Wisconsin researcher, James Reinartz (1997), tested cold weather stump application using 25% concentration of glyphosate herbicide on glossy buckthorn and obtained 92 to 100% control. I have used straight glyphosate concentration on the freshly cut stumps of Asiatic bittersweet vine in November and obtained a 98 % kill in a small, but heavy, infestation of vines that were between two and four inches in diameter. Cold weather control frees up time for control efforts that is not available during the summer months and is especially useful on overgrown Asiatic bittersweet individuals.

7. The above suggested example may be modified to suit existing site conditions and the level of Asiatic bittersweet vine infestation.

To learn more about Asiatic bittersweet vine, visit: www.invasive.org.

For additional information about exotic invasives, refer to Bruce’s article: “Controlling Small Scale Infestations of Exotic Invasive Plant Species: Ecological and IPM Information for Landscapers and Homeowners.”

Part I: The New Group of Pests Differs from Insects and Diseases
Part II: IPM Control Strategies for Exotic Invasive Plants
Part III: Landscape and Ecosystem Damage: A Brief Introduction

Individual Exotic Invasive Plant Fact Sheets:

Glossy Buckthorn

Common Buckthorn

Asiatic Bittersweet Vine

Winged Euonymus

Multiflora Rose

Japanese Barberry

Tree-of-Heaven

About the Author

Bruce Wenning has university degrees in plant pathology and entomology and is an ELA Board member and regular contributor to the ELA Newsletter. Bruce also spearheads the effort to expand ELA’s website content. Watch for his upcoming articles with information about individual invasive species. He is a horticulturist at The Country Club, Brookline, MA where he continues his battle with exotic invasive plant species.

Bindweed Control – How To Kill Bindweed In The Garden And Lawn

Any gardener that has had the displeasure of having bindweed in their garden knows how frustrating and infuriating these weeds can be. Controlling bindweed can be difficult, but it can be done if you are willing to take the time. Below, we have listed some different ways how to control bindweed.

Identifying Bindweed

Before you can get rid of bindweed, you need to make sure that the weed you have is bindweed. Bindweed (Convolvulus) is often called wild morning glory because it looks like morning glory. Bindweed is a climbing vine. Normally, the first signs that you have bindweed will be thin thread-like vines that wrap themselves tightly around plants or other upward objects.

Eventually, the bindweed vines will grow leaves, which are shaped much like an arrowhead. After the leaves appear, the bindweed vine will start growing flowers. Bindweed flowers are trumpet shaped and will be either white or pink.

How to Control Bindweed

Part of why it is so hard to get rid of bindweed is that it has a large and hardy root system. Single attempts to remove bindweed roots will not be successful. When controlling bindweed, the first thing to remember is that you will need to make several attempts of the bindweed control method you choose several times before you can successfully kill bindweed.

Organic and Chemical Approaches for Bindweed Control

Both boiling water (organic) and non-selective herbicides (chemical) can be used to get rid of bindweed. Both of these options can kill any plant where applied. These methods are ideal for areas where bindweed is growing but there are no other plants you wish to save. These would be areas like driveway cracks, empty vegetable beds and vacant lots.

To use boiling water to kill bindweed, simply boil some water and pour it on the bindweed. If possible, pour the boiling water about 2-3′ beyond where the bindweed is growing so that you can get as much of the roots as possible.

If you are using an herbicide, apply it heavily to the bindweed plant and re-apply every time the plant reappears and reaches 12 inches (30 cm.) in length.

Repeated Pruning to Kill Bindweed

Another popular method for controlling bindweed is to prune the vines back to the ground repeatedly, whenever they appear. Take a pair of scissors or shears and snip the bindweed vine off at ground level. Watch the location carefully and cut the vine back again when it appears.

This method forces the bindweed plant to use up its energy reservoirs in its roots, which will eventually kill it.

Controlling Bindweed with Aggressive Plantings

For as stubborn as bindweed can be, it has a very hard time competing with other aggressive plants. Often, bindweed can be found in poor soil where few other plants can grow. Improving the soil and adding plants that spread densely will force the bindweed out of the bed.

If you have bindweed in your lawn, dethatch the lawn and apply fertilizer to help your lawn grow more compactly, which then makes it far more difficult for bindweed to grow.

Note: Chemical control should only be used as a last resort, as organic approaches are more environmentally friendly.

Oriental Bittersweet Information: Guide To Oriental Bittersweet Control

Many people asking about oriental bittersweet (Celastrus orbiculatus) aren’t interested in growing it. Instead, they want to know how to eradicate oriental bittersweet. This climbing woody vine, also known as round-leaved or Asian bittersweet, was once planted as an ornamental. However, it escaped cultivation and spread into wild areas where it crowds out native trees, shrubs and other vegetation. Read on for information about killing oriental bittersweet.

Oriental Bittersweet Information

Oriental bittersweet plants are vines that grow up to 60 feet long and can get four inches in diameter. They are fast-growing and attractive, with light green, finely toothed leaves. The round yellow fruits split to reveal red berries that birds happily devour all winter long.

Unfortunately, oriental bittersweet plants have many very effective methods of propagation. The bittersweet plants spread within colonies by seeds and root sprouting. Oriental bittersweet control becomes necessary because

the vines also spread to new locations.

Birds love the berries and disperse the seeds far and wide. The seeds remain viable for a long time and spout well in low light, so anywhere they fall, they are likely to grow.

Oriental Bittersweet Control

The vines pose an ecological threat since their vigor and size threatens native vegetation at all levels, from the ground to the canopy. When thick masses of oriental bittersweet plants sprawl over shrubs and plants, the dense shade can kill the plants beneath.

Oriental bittersweet information suggests that an even greater threat is girdling. Even the tallest trees can be killed by the vines when they girdle the tree, cutting off its own growth. The weight of the dense vines can even uproot a tree.

One victim of oriental bittersweet plants is the native variety American bittersweet (Celastrus scandens). This less aggressive vine is being eliminated through competition and hybridization.

How to Eradicate Oriental Bittersweet

Killing oriental bittersweet or even just controlling its spread is difficult, a task of many seasons. Your best bet is not to plant the vine at all nor dispose of live or dead seed-containing material in an area where the seeds may grow.

Oriental bittersweet control involves removing or killing oriental bittersweet on your property. Pull out the vines by the roots or repeatedly cut them down, keeping an eye out for suckers. You can also treat the vine with systemic herbicides recommended by your garden store. There are no biological controls currently available for this vine.

Southeast Exotic Pest Plant Council Invasive Plant Manual

Common Name: Oriental Bittersweet

Scientific Name: Celastrus orbiculata Thunb.

Oriental bittersweet is a serious threat to plant communities due to its high reproductive rate, long range dispersal, ability to root sucker, and rapid growth rate. Climbing Oriental bittersweet vines severely damage native vegetation by constricting and girdling stems. Vines can shade, suppress, and ultimately kill native vegetation. Oriental bittersweet has been shown to hybridize with the relatively rare American bittersweet (Celastrus scandens L.). Hybridization may lead to the loss of American bittersweet’s genetic identity through introgression. Both are members of the Celastraceae (Stafftree) family.

Height: Oriental bittersweet is a deciduous woody vine that may become a spreading, trailing shrub. Maximum height can reach 19 m (60 ft) depending on surrounding vegetation. Vines grow up to 10 cm (4 in) in diameter.

Leaves: Leaves are alternate and are variable in size and shape from oblong-obovate to suborbicular. Margins are crenate-serrate and base cuneate to obtuse. Petioles are 1-3 cm (0.4-1.2 in) long.

Stem: Stems and branches are round, glabrous, light to dark brown with discernible lenticels.

Flowers: Inflorescence is a few-flowered (3-7) axillary cyme. Flowers have 5 sepals and 5 petals, and are greenish-yellow in color. Varieties can be dioecious or monecious. Blooms in May.

Fruit: Fruit is green changing to bright yellow upon maturity. The globose fruits are 6-8 mm (0.2-0.3 in) in diameter, three valved with each fruit containing one to three seeds. Matures August-September.

Life History

Oriental bittersweet flowers in May in Tennessee. Hymenopterous insects, especially bees, are the primary pollinators, but wind pollination is also successful. Fruit ripens in August through September and remains on the stem into the winter. Seed dispersal is by birds or small mammals. Seedling germination is generally high (up to 95%) and begins in mid to late spring. The highest rate of seed germination is in lower light intensities. Seedlings increase photosynthesis two-fold when exposed to direct sunlight. The plants develop and expand by layering stolons and rootsuckers. Annual growth rate is from 0.3-3.0 m (1-12 ft) with little additional growth after about seven years.

Origin and Distribution

Oriental bittersweet is native to Japan, Korea, and northern China. It was introduced into the U.S. in 1860. Naturalized plants were first collected in Connecticut in 1916. Oriental bittersweet has become naturalized in 21 of 33 states in which it is cultivated. Present distribution is throughout the northeastern and southeastern U.S. extending to the southeastern Great Plains.

Similar Species

Oriental bittersweet is similar in appearance to American bittersweet and anyone surveying for Oriental bittersweet should verify identification. Oriental bittersweet differs from American bittersweet by having axillary inflorescences instead of terminal flower clusters. However, inflorescences are sometimes terminal in male Oriental bittersweet plants. A less reliable difference is the color of the outer covering of the fruit. The fruit of Oriental bittersweet is yellow while American bittersweet fruit is orange.

Habitat

Oriental bittersweet has a wide range of habitat preferences including roadsides, old homesites, thickets, and alluvial woods. Oriental bittersweet is shade tolerant, readily germinating and growing under a closed forest canopy.


Photo by James H. Miller


Photo by James H. Miller


Photo by James H. Miller


Photo by Jil M. Swearingen

Management Recommendations

Since Oriental bittersweet produces numerous seeds, extensive seed reserves can become established in the soil within a year or two. Seeds of Oriental bittersweet remain viable for several years and control actions must continue until seed sources are eliminated.

Mechanical Control

Cutting: Cut climbing or trailing vines as close to the root collar as possible. This technique is feasible on small populations; as a pretreatment on large impenetrable sites; in areas where herbicide cannot be used; or if labor resources are not sufficient to adequately implement herbicidal control. This treatment will prevent seed production and strangulation of surrounding woody vegetation. Oriental bittersweet will resprout unless cut so frequently that its root stores are exhausted. Treatment should begin early in the growing season and be repeated at two-week intervals until autumn.

Grubbing: This method is appropriate for small initial populations or environmentally sensitive areas where herbicides cannot be used. Using a pulaski or similar digging tool, remove the entire plant, including all roots and runners. Juvenile plants can be hand pulled depending on soil conditions and root development. Any portions of the root system not removed will potentially resprout. All plant parts, including mature fruit, should be bagged and disposed of in a trash dumpster to prevent reestablishment.

Herbicidal Control

Stump Treatment: Use this method in areas where vines are established within or around non-target plants, or where vines have grown into the canopy.

    Glyphosate: Cut the stem 5 cm (2 in) above ground level. Immediately apply a 25% solution of glyphosate and water to the cross-section of the stem. This procedure is effective at temperatures (as low as 40°F) and may require a subsequent foliar application of glyphosate.

    Triclopyr: Cut the stem 5 cm (2 in) above ground level. Immediately apply a 25% solution of triclopyr and water to the cross-section of the stem This procedure remains effective at low temperatures (<60°F) as long as the ground is not frozen. A subsequent foliar application may be necessary to control new seedlings.

Foliar Spray Method: Use this method to control large populations. It may be necessary to precede foliar applications with stump treatments to reduce the risk of damaging non-target species.

    Glyphosate: Apply a 2% solution of glyphosate and water plus 0.5% non-ionic surfactant to thoroughly wet all foliage. Do not apply so heavily that herbicide will drip off leaves. Glyphosate is a non-selective systemic herbicide that may kill non-target partially sprayed plants. Ambient air temperature should be above 65°F.

    Triclopyr: Apply a 2% solution of triclopyr and water to thoroughly wet all foliage. Do not apply so heavily that herbicide will drip off leaves. The ideal time to spray is after surrounding native vegetation has become dormant (October-November) to avoid affecting non-target species. A 0.5% concentration of a non-ionic surfactant is recommended in order to penetrate leaf cuticle. Ambient air temperature should be above 65°F.

Bibliography

Dreyer, G.; Baird, L.; Fickler, C. Celastrus scandens and Celastrus orbiculatus: comparisons of reproductive potential between a native and an introduced woody vine. Bulletin of the Torrey Botanical Club 114(3):260-264; 1987.

Dreyer, G. Efficacy of triclopyr in rootkilling Oriental bittersweet and certain other woody weeds. Proceedings of the Northeastern Weed Science Society Vol. 42:120-121; 1988.

Lutz, H. Injury to trees caused by Celastrus and Vitis. Bulletin of the Torrey Botanical Club 70(4):436-439; 1943.

McNab, W. H.; Meeker, M. Oriental bittersweet: a growing threat to hardwood silviculture in the Appalachians. Northern Journal of Applied Forestry 4:174-177; 1987.

Patterson, D. The ecology of Oriental bittersweet, Celastrus orbiculatus, a weedy, introduced ornamental vine. Durham, NC: Duke University. Dissertation. 1974.

Patterson, D. T. Weed watch: Oriental bittersweet. Weeds Today 6(1):16; 1975.

Patterson, D. T. Distribution of Oriental bittersweet in the United States. Journal of the Elisha Mitchell Science Society 89(4):245; 1973.

Patterson, D. T. Photosynthetic acclimation to irradiance in Celastrus orbiculatus Thunb. Photosynthetica 9(2):140-144; 1975.

Wheeler, L. Oriental bittersweet: avian dispersal in winter in relation to other species of fruiting plants. Undergraduate Individual Study Report, Zoology Department, Connecticut College, Unpublished. 1987.

White, O.; Bowden, W. Oriental and American bittersweet hybrids. Journal of Heredity 38(4):125-127; 1947.

Oriental bittersweet, a crafty invader

January 25, 2018 Oriental bittersweet, an invasive plant, should never be used in holiday crafts. Photo: Minnesota Department of Agriculture

As you prepare for the winter holidays with festive decorations and good cheer, be on the lookout for an invasive forest killer: Oriental bittersweet. This attractive vine has been used in holiday decorations and other crafting items. Fruiting branches, which have red berries and yellow fruit capsules, make wreaths charming but easily spread seed.

Oriental bittersweet is designated a Minnesota noxious weed on the eradicate list. If craft arrangements such as wreaths are placed outside, birds can eat the fruit and move the seed to new locations. Composting spent arrangements has resulted in new infestations.

Oriental bittersweet, Celasturs orbiculatus, is native to eastern Asia and was planted in North America for ornamental uses as early as 1736. It has escaped cultivation and is strangling and smothering entire forest stands. It can dominate tree canopies and reduce forest-floor light to levels that prevent other plant species from growing. The vine weight, compounded with snow and ice or high wind, can break trees.

Fortunately, the eastern two-thirds of the United States is home to the native vine American bittersweet. You can enjoy the attractive look and craftiness of American bittersweet decorations while feeling confident you are not spreading an invasive species.

A few key points to help identify Oriental (bad) bittersweet from American (good) bittersweet in crafts:

  • Seed capsules: Oriental bittersweet has yellow seed capsules on red berries (give a yell when you see yellow), whereas American bittersweet has orange seed capsules on red berries (orange is okay).
  • Berry placement: Oriental bittersweet has berries strung-out along the stem (strung-out is bad), while American bittersweet’s berries are all clustered near the end (saving the best for last).

Oriental bittersweet management

Winter is a great time of year to identify vines in the landscape. The berries will be visible and fairly showy when the summer foliage is down.

Management in the forest will likely involve either a foliar spray (spraying the leaves), cut stump (cutting the vine and treating the cut stump) or basal bark herbicide treatment (using an herbicide mixed with bark oil that will penetrate the bark). For large infestations, contact the Minnesota Department of Agriculture before proceeding with treatment. Small vines can be pulled and bagged or burned. It is important to note when pulling that these vines can root where they touch the ground, not just at the roots, so pulling them and tossing the vines on the ground will not kill them. The vines should either be treated with an herbicide or bagged or burned. Burning live Oriental bittersweet will not kill it, but will instead lead to a new flush of vigorous growth.

Clean boots, clothing and gear before moving about or going home from a day searching for or treating Oriental bittersweet or any invasive plants.

For more information, visit University of Minnesota Extension’s My Minnesota Woods website.

To report Oriental bittersweet in Minnesota

If you think you have found Oriental bittersweet, please report it in one of these three ways:

  • Call Arrest the Pest (you will be asked to leave a message): 1-888-545-6684
  • Email a report with a GPS or street location and a photo to Arrest the Pest.
  • Report online via an online form.

Angela Gupta, University of Minnesota Extension, and Monika Chandler, Minnesota Department of Agriculture

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