Hedge bindweed or bellbind (Calystegia sepium) with its pure white trumpet flowers is a familiar sight, choking plants in borders and twining around any plant shoot or cane. The smaller field bindweed (Convolvulus arvensis) with white or pink flowers is problematic in long grass and bare soil.
What is bindweed?
Bindweed refers to two similar trumpet-flowered weeds, both of which twine around other plant stems, smothering them in the process.
They are not easy to remove as they persist from a perennial root system. The roots are usually white and brittle and, if broken, are able to regenerate from the smallest sections.
Calystegia sepium (bellbind or hedge bindweed) climbs with strong twining stems, has large heart-shaped leaves and large white trumpet flowers. It is most often seen as a hedgerow plant or weed, scrambling over and often smothering hedges and shrubs of all sizes and even smaller ornamental trees.
Convolvulus arvensis (field bindweed) is a weaker-stemmed plant, with smaller white or pink trumpet-shaped flowers, but otherwise similar in appearance to bellbind.
Bindweeds are a problematic for a number of reasons;
- Bellbind spreads mainly from sections of underground stem (rhizome) or root. The roots of bellbind may penetrate up to 5m (16ft) deep or more and spread rapidly, but most growth is from white, shallow, fleshy underground stems. Established colonies can spread outwards by 2m (6ft) or more in a single season
- Even very small sections are capable of producing shoot growth and can unwittingly be brought into gardens hidden among plant roots and in soils or manures
- Bellbind produces seeds infrequently, but they can reportedly remain viable in the soil for many years
- The roots of field bindweed are similarly deep-rooting to those of bellbind, with underground stems and shoots arising directly from the roots. Established colonies may extend outwards by 2m (6½ft) or more in a season
- Field bindweed produces seeds freely and they can remain viable in the soil for several years
- These weeds are difficult to eradicate by cultural methods as their roots can extend deep into the soil
- Physical barrier: By persistent digging and hoeing it is possible to eradicate these weeds in a couple of years, although new colonies can establish from seed or from roots on neighbouring land. Because of this, and wherever feasible, it can pay to insert vertical, solid barriers (45cm/18in deep) into the soil along fences and other boundaries
- Digging: Fork out to remove as much of the roots when carrying out any routine autumn and winter digging. In spring as new growth appears, dig out new shoots
- Hoeing: In areas where it is not possible to dig without disturbing plant roots, sever the weed at ground level with a hoe. This will need to be repeated throughout the growing season as new growth reappears
- Glyphosate is a non-selective weedkiller applied to the foliage, where it is translocated throughout the weed. Tougher formulations are worth trying (e.g. Scotts Roundup Ultra 3000, Scotts Tumbleweed, Bayer Tough Rootkill, Bayer Super Strength Glyphosate or Doff Knockdown Maxi Strength Weedkiller)
- Being non-selective, it is essential to avoid spray drift onto neighbouring plants. It is important to have good leaf coverage so that as much chemical is absorbed as possible
- It is usually more effective when the weed has reached the flowering stage, but can be effective well into the autumn. Early spring applications are generally less successful
- Spraying in the early evening is more effective than spraying during the day
- Where the weed has started to twine into plants it is possible to carefully untwine the stems and lay them on bare ground before spraying the foliage
- Alternatively, in spring, insert vertical bamboo canes close to the weed to encourage it to grow up the canes rather than smother plants. The stems can then either be left on the cane and carefully spot-treated with glyphosate (Scotts Roundup Gel) or untwined and laid on the bare soil or an adjacent pathway before being sprayed
- Bayer Long Lasting Ground Clear containing glyphosate/flufenacet/metosulam comes in a soluble sachet. It can be applied once a season to natural surfaces where no plants are to be grown, and can also be applied under and around established woody trees and shrubs, including roses. This product kills off existing small green growth and prevents or checks developing growth. Check manufacturer’s recommendations before use to avoid damaging sensitive plants
- Both weeds can be persistent when growing in the lawn. Regular mowing, and the use of lawn weedkillers, will help keep them under control and eventually eliminate the plants
Weedkillers for gardeners (Adobe Acrobat pdf document outlining weedkillers available to gardeners; see sections 4 and 5)
Chemicals: using a sprayer
Chemicals: using safely and effectively
Chemicals: using spot and broad-scale weedkillers
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Common and botanical names Hedge bindweed, bellbind (Calystegia sepium) and field bindweed (Convolvulus arvensis)
Areas affected Uncultivated ground, beds, borders, paths, drives and lawns
Main causes Twining weed with creeping underground stems (rhizomes)
Timing Seen spring to autumn; treat from summer to autumn