The Hedge Bindweed or Morning Glory: An Invasive Plant
A Beautiful and Invasive Vine
The hedge bindweed is an annoying vine that most people hate to see in their gardens. 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 which are white in colour and very beautiful. These flowers open in the morning and close in the evening and in dim light, giving the bindweed its alternate name of morning glory. (Some cultivated relatives of the hedge bindweed have this name as well.) Other lovely names for this plant include heavenly trumpets, bugle vine, and bellbind. All of the photos of the plant in this article were taken by me.
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. 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 species.
The Hedge Bindweed
The scientific name of the hedge bindweed is Calystegia sepium. The plant is native to eastern North America and is an introduced plant in British Columbia (and in many other parts of the world). In BC, it's classified as an invasive plant, a noxious weed, or a nuisance plant, depending on the organization that's classifying the bindweed.
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.
Hedge bindweed is a perennial plant. Its roots are quite shallow, but they spread sideways and branch extensively. The horizontal "roots'' are actually underground stems, which are known as rhizomes. The rhizomes develop buds which produce shoots that emerge from the soil.
Stems and Leaves
An above-ground stem of bindweed may be as long as three meters (about ten feet). If a stem is traced from its base towards its tip we can see that the stem spirals around its support in a counterclockwise direction.
The large leaves of the hedge bindweed 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 at an angle of almost ninety degrees.
Hedge Bindweed or Calystegia sepium
The video above shows some lovely scenes involving hedge bindweed. At one point the narrator says that the plant is edible but should be eaten in small quantities because it's a purgative (laxative). Health professionals say that eating bindweed may be an unsafe practice.
Flowers and Fruits
The tubular flower is made of fused petals which 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.
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 different subspecies of hedge bindweed exist, each with slightly different characteristics.
The showy flowers of bindweed are big, bright, and beautiful but have no scent. A wall or carpet of hedge bindweed with many open flowers is an attractive sight. 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, Convolvulus arvensis. The easiest way to distinguish one plant from the other is to look at the flowers and the leaves. In the field bindweed, the two bracts below the flower are located one half to two inches down the flower stem instead of at the base of the flower. In addition, the tip of a field bindweed leaf is a rounded point instead of a sharp point and the basal lobes of the leaf are pointed instead of having the cut-off appearance of a hedge bindweed leaf.
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.
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.
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 emerge 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 process needs to be done consistently as new shoots arise from seeds or bits of rhizome.
Another physical way to remove hedge bindweed is to cover all the above ground parts with dark plastic or some other opaque substance, blocking them from light. This will eventually starve the plant, since its leaves can't make new food and the root will run out of stored food. There are herbicides that can be used as well if a person doesn't mind using chemical control.
How to Remove Bindweed
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. However, frequent inspection of an area and dealing with "outbreaks" as soon as they're seen will enable someone to stay in control, as I know from experience. The job becomes harder If a person has a larger area to inspect, though.
Hedge bindweed can definitely be a nuisance. 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.
© 2012 Linda Crampton