The Hedge Bindweed or Morning Glory: An Invasive Plant in BC
A Beautiful and Invasive Vine
The hedge bindweed (Calystegia sepium) is an annoying vine that most people hate to see in their gardens where I live. The stem grows rapidly and twines around other plants as it elongates. It eventually forms dense, leafy tangles that are difficult to remove and can interfere with the growth of the encircled plants.
The young hedge bindweed grows horizontally at first, its stem winding around other objects that it encounters. These objects may be plants or inanimate objects. If the bindweed encounters a vertical support it becomes a climbing plant and spirals around the support as it climbs. Bindweed “binds” objects as it encircles them, giving the plant its traditional name.
I live in British Columbia, where hedge bindweed is an introduced plant. It's invasive and a nuisance, but it does have one attractive quality. In the summer it produces large, trumpet shaped flowers that are white in colour and very beautiful. These flowers open in the morning and close in the afternoon or evening and in dim light, giving the bindweed its alternate name of hedge morning glory. All of the photos of the plant in this article were taken by me.
Other names for the hedge bindweed include heavenly trumpets, bugle vine, bellbind, great bindweed, and wild morning glory. It's classified as invasive in at least part of Washington in the United States as well as in British Columbia. The state is BC's southern neighbour.
The Morning Glory Family
The morning glories or bindweeds belong to the Convolvulaceae family of plants, which contains many different species. All of them have the trumpet or funnel shaped flower of the hedge bindweed, but the flowers of some species are brightly coloured instead of white. Some of these are popular garden plants and often have the term "morning glory" in their name. Most of the plants in the family—although not all of them—have winding stems. The name of the family comes from the Latin word "convolvere", which means "to wind".
A very popular member of the morning glory family is the sweet potato (Ipomoea batatus). Its edible root is starchy, sweet, and nutritious. White-fleshed and orange-fleshed varieties of sweet potato are available. The orange-fleshed kind is sometimes called a yam in stores, but true yams belong to a different family of plants. Sweet potatoes have purple flowers or white-rimmed flowers with a purple throat, depending on the variety.
The Hedge Bindweed
Calystegia sepium is native to eastern North America and is an introduced plant in British Columbia. Some people claim that it's native to other areas. Its history is a little murky. The plant can be found in Europe, Asia, and New Zealand as well as in the United States and Canada. In BC, it's classified as an invasive plant, a noxious weed, or a nuisance plant, depending on the organization that's classifying it.
Whatever label is used to describe it, hedge bindweed is a very annoying plant when it grows where it's not wanted. It lives in a variety of habitats, including gardens, fields, beside roadways and trails, and in open woodlands. Interestingly, the plant is not classified as a nuisance everywhere in North America, especially in the eastern portion of the continent. Some people actually like its ability to cover unsightly objects and appreciate the beauty of its flowers.
The plant is a perennial. Its roots may be quite deep, but this is not the only problem with respect to its underground parts. The structures that look like horizontal roots are actually underground stems, which are known as rhizomes. The rhizomes spread sideways and branch extensively. They develop buds and produce shoots that emerge from the soil.
Stems and Leaves
An above-ground stem of bindweed may be as long as three metres (about ten feet) or sometimes even longer. The large leaves of the plant are shaped like arrow heads. They have a pointed tip and two extensions or lobes at their base, which are often called dog ears.
The leaves are green on their upper surface and grey-green on their lower surface. They are attached to the stem by long petioles. The leaves hang from the petioles, sometimes at an angle of almost ninety degrees.
The video above shows some lovely scenes involving hedge bindweed. At one point the narrator says that the plant should be eaten in small quantities because it's a purgative (laxative). Health professionals say that eating bindweed may be an unsafe practice, especially for some people and in certain situations. More detail is given in the last reference at the end of this article.
Flowers and Fruits
The tubular flower is made of five fused petals that are pleated or creased. The outermost, flattened section of the flower is known as the rim. The rim may be curled backwards at its edge. The inside of the tube is known as the throat. There are two leafy bracts at the base of the flower. These cover the sepals.
The flowers near my home have a white rim and a yellow-green throat. Some bindweed flowers have a pale pink flower with white stripes. A number of subspecies of hedge bindweed exist, each with slightly different characteristics.
The showy flowers of the plant are big, bright, and beautiful. They have no scent that can be detected by humans. A wall or carpet of hedge bindweed with many open flowers is an attractive sight. The flowers are pollinated by bees and other insects. The fruit of the plant is a capsule and contains one to four seeds, which are usually brown or black when they are mature.
Hedge bindweed is often confused with the field bindweed, or Convolvulus arvensis. The easiest way to distinguish one species from the other is to look at the flowers. In the field bindweed, the two bracts below the flower are located one half to two inches down the flower stem instead of immediately at the base of the flower. In addition, the field bindweed has smaller flowers, leaves, and bracts and a weaker stem than its relative.
Although hedge bindweed is a nuisance, it's considered to be less invasive than field bindweed. Someone battling hedge bindweed on their property would probably disagree with this observation, though. Either plant can be a problem.
An Invasive Plant
Once hedge bindweed becomes established in an area, it's very hard to remove. Bindweed grows between other plants as well as over them. This prevents the other plants from getting all the nutrients and light that they need. It also makes it tricky to remove the bindweed without damaging the supporting plants. Sometimes the cover of bindweed is so dense that it causes the collapse of a supporting plant and kills it.
Hedge bindweed stops growing in winter and the leaves die. The plant itself hasn't died, though. In summer it becomes active again and the buds on the rhizomes produce new shoots.
How to Remove Bindweed
If someone wants to remove bindweed by physical means, it's necessary to remove all of the root and rhizomes so that the plant can't regenerate. This is hard to do, since the rhizomes are very long. Even a small section left in the soil can generate a new shoot.
It's important to be vigilant and remove any young bindweed that emerges from the soil. This will be a much easier task then trying to remove mature bindweed that has become entwined around other plants. The removal needs to be done consistently as new shoots arise from seeds or bits of rhizome. The process will probably take more than one season.
Another method that reportedly gets rid of hedge bindweed is to cover all of the above ground parts with dark plastic or some other opaque substance, blocking them from light. This should eventually starve the plant, since its leaves can't make new food and the root will run out of stored food. The process sounds logical, but I've never tried this method of getting rid of bindweed. The video below describes the removal of the plant.
Specific herbicides can be used to destroy the plant if a person doesn't mind using chemical control. The dangers associated with a particular herbicide should be investigated. Biological control agents are available in some areas, but they may not be available to the public.
Bindweed Battle and Beauty
The battle with unwanted bindweed is likely to be a long one. The seeds can survive for years in the soil and small pieces of root or rhizome can produce new shoots. Frequent inspection of an area and dealing with "outbreaks" as soon as they're seen can enable someone to stay in control, however, as I know from experience. The job becomes harder if a person has a large area to inspect.
Hedge bindweed can definitely be a nuisance. I'm not happy when I see it in my garden. I always pause to look at the plant's flowers when I discover them on a walk, though. Despite bindweed's annoying and sometimes destructive habit of covering other plants, it's hard for me to ignore the beauty of its flowers. The term "morning glory" is very apt.
- Information about hedge bindweed from the Ontario Ministry of Agriculture, Food and Rural Affairs (This site uses the older scientific name for the plant, which was Convolvulus sepium.)
- Facts about Calystegia sepium in the eastern United States from the Native Plant Trust Go Botany Project
- Invasive plants with biological control methods (including the hedge bindweed) from the Government of British Columbia
- The hedge bindweed plant in King County, Washington
- Facts about bindweed (hedge and field) from the Royal Horticultural Society
- Hedge bindweed safety concerns when eaten from WebMD.
Questions & Answers
How can I destroy bindweed and not my flowers?
My favorite methods of removing bindweed are to prune the vine at ground level as soon as a shoot appears and to dig up the underground parts. These processes have to be repeated, but, eventually, destroy the vine. The process may take two or more years, however. Vigilance and determination are needed.
Cutting the vine as soon as it appears above the soil will weaken the bindweed and stop it from surrounding desirable plants. A more permanent solution is to dig into the soil to remove the underground parts. This may be hard to do if other plants are growing in the area, but it’s the best way to get rid of the plant eventually.Helpful 13
© 2012 Linda Crampton