If you garden, chances are that you have encountered bindweed (AKA Creeping Jenny). You can mow it, pull it, and cultivate around your vegetable plants all season and yet every day seemingly find new bindweed plants. Have you ever wondered if your control strategies are actually helping the bindweed to grow?
Penn State Extension (see Field Bindweed link below) offers a good description of bindweed: “A vinelike perennial, field bindweed belongs to the morning glory family (Convolvulaceae). Its slender stems can form dense tangled mats up to 10 feet (3 m) across, and climb by wrapping around nearby plants and objects.”
In case you’ve never seen bindweed before, here’s what it looks like. Notice the leaves shaped like blunt arrowheads and the easily severed taproot. This taproot may extend many feet into the soil and can survive soil temperatures as low at 20°F which means that it can come back year after year from the roots.
Figure 1. Typical bindweed leaf shape and taproot (click to zoom).
This taproot generates many side roots extending one to three feet away from the taproot. These side roots produce buds underground that can develop into new plants. That’s right, if you manually remove bindweed plants as shown above, the side roots left in the soil are capable of becoming new plants.
If, rather than pulling weeds, you till between the rows in your garden every few weeks you may be chopping up these roots. And root pieces as short as two inches can form new plants! (I learned that mistake the hard way managing a community garden in Wyoming.)
If the bindweed is allowed to grow to maturity it will produce white or pink funnel shaped flowers that bloom from June through September. Typical of species in the morning glory family, the flowers open during the early morning hours and then close later in the day.
I think the flowers are kind of pretty (plant nerd here), but if these flowers are left unchallenged, they will produce seeds. One bindweed plant may produce as many as 550 seeds that can remain viable in your soil for 20 years! So, in addition to controlling bindweed in your garden, you need to control bindweed around the garden, in surrounding fields and ditches, and along fence lines if you want to prevent the production and spread of seeds.
Bindweed is found throughout the United States in all kinds of soils, so it’s not picky about growing conditions. It is also drought tolerant and when water is limited it will outcompete most of your garden plants.
Figure 2. This field was plowed two weeks ago. See the difference between the growth of the bindweed and other common weeds?
Controlling Bindweed With or Without Chemicals
Bindweed is sensitive to shade, so if you can manually remove it early in the season fast growing garden crops may be able to help suppress its growth. However, if the bindweed is more than a year old, with a well-established root system, shading won’t even slow it down. It will even grow several feet under plastic or landscape fabric to emerge from the holes you cut for your vegetable plants.
Effective non-chemical control requires a multi-pronged approach including:
- Disruption of carbohydrate storage by deep tillage of the root system (so unfortunately no till is not a good choice if you’re trying to control bindweed without chemicals)
- Competition for light from other plants (i.e. vegetable plants, cover crops, perennial grasses or forages)
- Prevention of seed production (mowing will not reduce bindweed infestations, but can reduce seed production if timed to prevent flowering)
- Constant manual removal of top growth (yes, that means getting on your hands and knees and gently pulling young bindweed plants before they have a chance to establish)
Chickens are another non-chemical control option. They eat bindweed leaves and stems and expose crowns and roots, further depleting root carbohydrate reserves. However, chickens will be just as happy to eat your vegetable plants and pose a food safety risk if allowed in the garden within 120 days of harvest, so they should only be used after you’ve finished harvesting your crops for the season.
If you’ve tried all of the above and still can’t seem to get your bindweed under control you may want to consider chemical options. Contact herbicides can kill back the aboveground growth (and may be useful for preventing seed production), but their effects are only temporary because the plant will just send up new shoots from the root buds.
Systemic herbicides are more effective as they are translocated throughout the plant. Systemic herbicides should be applied when bindweed is in bud or the early bloom stage because that’s when root reserves are lowest and translocation from the leaves to the roots is most active.
Unfortunately bindweed is a broadleaf plant like most of the vegetables in the garden, so if you decide to use herbicides you must be careful to avoid damaging your crops at the same time. One way to accomplish this is to place a rubber glove on your hand and wear a cotton glove or sock over it that you can spray or dip into a small container of systemic herbicide like glyphosate (Roundup) or 2,4-D, and then carefully wipe it on the leaves of the bindweed. This procedure will need to be repeated about every 10 days until the bindweed dies.
Regardless of the herbicide chosen, chemical control is most effective when combined with the non-chemical control options described above.
For more information:
Bindweed Identification and Control Options for Organic Production
Field Bindweed Control Alternatives