This is the second in a series on invasive plants. The Pepperell Garden Club has designated this as “ Invasives Awareness Year”. Please clip out & keep for your reference.
This month, I will discuss Oriental Bittersweet, due to its popularity as an autumn home & garden decoration.
Fall foliage, apple picking, pumpkins, and migrating birds, are but a few symbols of the autumn of the year.
Unfortunately, another popular seasonal motif is Oriental bittersweet. We decorate our doorways and centerpieces with it, at its height of ripeness, ready to drop its showy berries and invade our yards. No doubt you have seen it draped over the trees along the highways.
Peter Alden, author, naturalist and invasives awareness guru of Concord, Massachusetts states “ a lot of people don’t know that those berries contain seeds. After the holidays, they may chuck the plants in their compost or the woods. Each one of these fruits is an ecological time bomb, killing the trees you threw them under”.
Every new gardener clamors for this “desirable” plant in their own gardens. Until they find out how problematic it is.
The Information below is taken from: Invasive.org, and enature.com
DESCRIPTION: Oriental Bittersweet (Celastrus orbiculatus)
- Introduced from China around 1860 as an ornamental, and shown to hybridize with American bittersweet, potentially leading to a loss of genetic identity.
- Twining, deciduous, woody vine that grows in masses, up to 60 ft.
- Leaves: round or ovate, toothed, light green to yellow, 2-5 in. long.
- Fruit: yellow to yellow-orange capsule splits to reveal showy scarlet fruit; fruits rise in clusters from leaf axils.
- Flower: May–June.
- Habitat: Woodland edges, marshes, coastal areas, roadsides, fence rows, fields, disturbed habitats
Prolific vine growth allows it to encircle, girdle, shade out and even kill large trees. Trees become weighted down, often resulting in the snapping of limbs, especially during high wind or severe winter conditions.
Birds eat the berries, passing them intact through their digestive system and spawning new bittersweet plants. I have found numerous seedlings under my crabapple trees.
Some consider it “junk food” for the birds; a desperation winter food. But more nourishing, native food is needed for survival during their long southern migrations and the chill of cold weather.
However, this plant does not need the birds help to proliferate. Most seeds that contact the soil will surely become a tangle of foliage, in as little as one year.
Every berry contains four seeds, and every mature vine can be laden with thousands of individual berries.
My husband and I have battled this invasive in our yard for many years. Unless you keep at it, its a huge challenge to eradicate. Also, notify your neighbors if you see it on adjoining property. This plant does not respect lot lines, and a neighborhood effort is the only real solution. You may control it in your yard, but the birds will still be spreading the seeds.
Below are suggestions for its control, sourced from The N. E. Wildflower Society, and From About.com.
TREATMENT: Oriental Bittersweet (Celastrus orbiculatus)
- Can pull small plants, but must get entire orange root network.
- In late summer or early fall, apply 25% solution of triclopyr (Ortho Brush-B-Gon) to cut stems – more established stands may require cutting earlier in season and then spraying re sprouted foliage 1 month later.
- Pick a sunny day for spraying, with little or no wind.
- For bittersweet vine growing on the ground or on a wall, heavily spray the leaves and vines.
- For bittersweet climbing up a tree, you may wish to “paint” the herbicide on, so as to preclude damaging the tree with a stray mist from your sprayer.
- This product is designed to kill woody plants, making it effective against not only bittersweet, but also another nuisance vine: poison ivy plants. But it will kill many other plants, too, so don’t use it near plants you wish to keep.
Always follow the exact label directions, and spray judiciously at the most effective time of that plant’s growth.
We have found that by cutting back the vine, bagging up the berries and spraying it has helped to control it. Recently, I draped the cut vines over a large brush pile, providing it does not touch the ground or have berries on it. This doubles as protection for wildlife throughout the year.
Again, the best strategy is early identification & intervention. By continued efforts and vigilance, you will greatly lessen or eradicate this persistent invasive. It is well worth the effort to save your gardens & surrounding landscapes from this formidable enemy.
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