Jennifer Schultz Nelson
Extension Educator, Horticulture
A plant to consider for a colorful fall display is American Bittersweet. But like a lot of plants, there are pluses and minuses to its use in the landscape.
American Bittersweet, Celastrus scandens, is native to North America. It is a vigorously growing woody vine that may reach a height and width of twenty feet or more. All parts of this plant are considered poisonous, but it is worth noting that Native Americans utilized American Bittersweet for medicinal purposes. It was used to treat cough, intestinal disorders, and venereal diseases. Some birds and squirrels will also eat the fruits of this plant without causing harm.
Today American Bittersweet's is prized for its ornamental value. The vine produces nondescript green flowers in the spring, followed by yellowish orange capsules that split in the fall to reveal bright red fruits which persist through the winter.
These sprays of berries are highly prized for fall flower arrangements and crafts. In some areas American Bittersweet is more and more difficult to find in the natural landscape because of people cutting the vines to use the berry sprays for fall decorations.
The fact that American Bittersweet is a vigorously growing vine may be viewed as a positive or negative aspect of this plant depending on what you want to achieve in your garden.
On a positive note, American Bittersweet provides color during a time when most everything else is fading fast in the garden. Late season color is a definite plus.
But on the other hand, anything described as "vigorously growing" may be just a little too energetic for your garden. This plant needs room to grow, as it will get up to twenty feet tall, and twenty feet wide. This is not a plant to tuck in a corner to fill in a small hole in your landscape. That would just be asking for trouble and a lot of cursing as you try desperately to keep it in check.
Another word of caution on this plant—although American Bittersweet may be found in nature climbing up trees and shrubs, it is not a good idea to encourage this behavior on young trees and shrubs you wish to keep alive. Mature trees may be able to tolerate a bittersweet vine. As bittersweet vines grow, they will tend to strangle whatever they are climbing on. So a sturdy trellis or other non-living structure is generally the best support for a bittersweet vine .
A common question I receive is from people who have planted American Bittersweet for its fruit, but their vine refuses to produce fruit. The most common reason for this problem is that like some other plants, such as holly, there are male and female bittersweet plants. You must have both male and female plants to successfully produce fruit. The male flowers on the male plant are hardly noticeable. Pollen from the male flowers pollinate the flowers on the female plant. The female flowers are also not much to look at, but later produce the showy and much desired yellow-orange capsules containing red fruits.
If the quantity of fruits produced is disappointing, consider a heavy pruning in the early spring. American bittersweet flowers on new growth. Without regular pruning, all the flowers will end up at the ends of the vine.
A relative of American Bittersweet that you should avoid at all costs is Oriental or Chinese Bittersweet , Celastrus orbiculatus. This bittersweet was introduced to the U.S. from Asia in the mid-1800's as an ornamental plant. It has the same desirable yellow-orange capsules filled with red fruits in the fall, but it is extremely aggressive, often growing sixty feet or more in a single season. It spreads rapidly from any bit of root or stem severed from the plant so removal by pulling is nearly impossible. Usually repeated applications of non-selective herbicides such as glyphosate (Roundup®) are necessary to control this invasive plant.
The easiest way to distinguish Oriental from American Bittersweet is the location of the flowers and fruits. American Bittersweet produces its flowers and fruit in clusters at the ends of branches, while Oriental Bittersweet produces flowers and fruit at the base of each leaf.
The better-behaved American Bittersweet will grow in just about any soil as long as it is not overly wet. Most vines establish better in full sun locations. Adequate sun is important for fruit production. Suggested cultivars for home landscapes are: 'Indian Brave'—which produces only male flowers, and 'Indian Princess'—produces only female flowers. Remember these must be planted together if you would like the female plant to produce the gorgeous yellow-orange and red fruits!