Bindweed or bellbind

(Calystegia sepium and Convolvulus arvensis) Bindweed or bellbind is a creeping, perennial weed that can smother and kill young and low-growing plants and twines around and chokes other plants.

There are two species of bindweed – field bindweed (Convolvulus arvensis) and the larger hedge bindweed or bellbind (Calystegia sepium). Both produce white, trumpet-shaped flowers, sometimes pink in Convolvulus arvensis, which do look attractive. But once it gets a hold in your garden it can quickly spread everywhere.

Field bindweed produces lots of seeds, whereas bellbind rarely produces seed; the seeds can remain dormant and viable in the soil for several years before germinating.

Bindweed spreads through its white, creeping, perennial “roots” – actually underground stems or rhizomes. These grow horizontally in the soil and can spread over great distances – up to 1.8m (6ft) in a year.

Bindweed colonises large areas of ground where it can smother underlying plants and even kill small ones. Its stems twine around other plant stems, smothering them and making it very difficult to remove from wanted plants. The roots can grow in between the roots of cultivated plants, making them difficult to remove and control.

• Beds
• Borders
• Lawns
• Gravel paths
• Between paving slabs
• Waste or uncultivated ground

New shoots begin to appear through the soil in late winter/early spring, quickly producing long, twining stems covered in large, heart-shaped leaves and lots of trumpet-shaped flowers. Its common names of bindweed and bellbind are very apt!

It dies down to its roots in late autumn and winter, lulling you into believing it has gone away! But it will grow back with a vengeance the following year.

As with most perennial weeds, never allow bindweed to become established. This will make it more difficult to fully control. Early identification and eradication is very important.

Start by digging out as much of the bindweed as possible, including the white, creeping roots. Be rigorous as the roots are brittle, easily break into smaller pieces and even a tiny piece left in the ground can re-grow into a new plant. A fork and hand fork are usually better tools than a spade and trowel, which will cut the roots into smaller pieces.

Once you have removed most of the bindweed, covering the soil with weed-control membrane (landscape fabric) or even thick black polythene will exclude light and may starve the roots, so they die. This can take several years until the bindweed is completely exhausted and eradicated.

If the roots are growing among established plants, you may have to lift these when dormant, from autumn to the end of winter, and tease out all the bindweed roots. Then replant in clean soil or pot them up for planting out later.

Regular hoeing, as soon as new growth appears above the ground, may weaken the plant – but this has to be carried out religiously, regularly and will take many years to be effective.

In lawns, regular mowing throughout the year and the use of lawn weedkillers should weaken it and eventually kill it.

You may unknowingly introduce bindweed into your garden when buying topsoil or manure, or in the rootballs of new plants. So be vigilant when buying these.

There are a number of weed control options available to treat bindweed. In addition to traditional weedkillers there are now also a range of more natural alternatives.

Contact weedkillers will burn and kill the foliage, but will have no effect on the roots, which will continue to grow, produce new leafy growth and spread further.

For best results, spray with a systemic weedkiller. A systemic weedkiller, which is absorbed by the leaves, then moves down to the roots to kill them.

To ensure the weedkiller works effectively:

• Spray the leaves when the bindweed is growing actively; this is mainly from March/April to September/October.
• The larger the leaf area present, the greater the amount of weedkiller that can be absorbed and move down to the roots. So don’t bother spraying when the growth first emerges through the soil – wait until the leaves unfurl and enlarge.
• Use a fine spray to thoroughly coat the leaves in small droplets.
• During the summer, spray in the evening to prevent the spray evaporating and to give maximum time for the spray to be absorbed. In spring or if overnight dew is forecast, spray earlier in the day to allow the spray to dry before dew falls.
• One application of weedkiller is unlikely to kill all the bindweed. You may need to spray once, allow the bindweed to die down, and then spray any regrowth again. Three or more applications a year, over a couple of years, may be needed to completely kill it, depending on how extensive the root system is.
   

Most contact weedkillers are total weedkillers – that is they will damage or kill any plants whose leaves they are sprayed on. Make sure you keep the spray off wanted plants – including lawns – and, if necessary protect plants by covering with polythene or similar when spraying.

Spraying established bindweed plants can be difficult as the stems and leaves twine around wanted plants and spraying will result in the weedkiller damaging or killing these plants.

Roundup Gel, which is smeared onto, and sticks to, the weed leaves, may be a better option when trying to kill bindweed growing through or close to wanted plants. Or, place bamboo canes in the soil early in the year where the bindweed is coming through the soil. It will twine up the canes, making it easier to isolate the weed and spray it.

Use weedkillers safely. Always read the label and product information before use.

As bindweed spreads by its underground roots, it may be coming into your garden from a neighbouring garden or surrounding waste ground. Unless you can stop this source, it will just keep coming back.

If it’s coming from a neighbour, have a quiet word and try and encourage them to control the bindweed in their garden.

If it is coming through from a relatively small area, it is possible to put a vertical physical barrier 45cm (18in) deep in the soil on your boundary to prevent it coming in. Suitable root control barriers and membranes are available from builders’ merchants.

• Spade
• Fork
• Hand fork
• Weed-control membrane
• Weedkillers