Bindweed in the garden
There is no organic solution other than digging up every white root, hard work but the only organic way!
I have also taken the liberty of referring your problem to Lynn (our Horticultural Advisor and Kitchen Gardener), and her reply also follows:
Bindweed is really difficult to get rid off, it is a perennial weed and can grow back from the tiniest piece of root left in the ground.
It’s not apparent from the customer’s Email what method she has used before so I’ve cut & pasted an extract from the RHS Website (to save me writing it up -need to get back to planting the leeks!). All the options are below.
• 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
• 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 be untwined and sprayed with glyphosate.
• 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
Therefore I feel Julian summed it up well regarding the only organic option. I can also add that from personal experience this method does work, we found it easy to make a quick difference in the first two or three years by digging each piece out manually, double digging in places where the roots snapped at one spade’s depth, and although we still have a few stubborn pieces remaining these are manageable on a yearly basis.
Good luck with eradicating the bind weed from your garden!
Kind regards Julian