Bindweed Unbound

Bindweed in bloom

When not strangling plants, bindweed looks innocent enough with its beautiful, slightly fragrant white or pinkish morning glory blooms.  Perhaps that’s part of the reason this European native is now found worldwide.  Unsuspecting gardeners may let it grow, finding out too late that they can’t contain its spread.  The only state in the U.S. that remains free of this pest is Alaska.  It was first was documented in San Diego, California, in 1884. 

Bindweed’s secret weapon lies beneath the soil.  It has both roots and rhizomes.  Vertical roots can penetrate the soil to a depth of 20 feet or more.  The horizontal rhizomes are usually less than a foot deep and comprise about 75% of the plant’s root system.  They are a whitish color and quite brittle, so that they break easily into smaller pieces.  Each piece—and it can be quite small—is capable of producing a new plant. 

Bindweed rhizomes

After bindweed seeds germinate, the resulting vines grow along the ground until they encounter something higher.  At that point they begin climbing upwards and covering whatever is in their path.  If it happens to be a plant stem, the vines will begin spiraling upward in a tight coil.  Left to its own devices, bindweed will completely smother whatever it has covered.

So how do you unbind bindweed and rid your garden of it?  ‘Tain’t easy.

You can try a chemical herbicide, but one application won’t kill it.  You’ll have to reapply, often many times, before the root system is totally destroyed.  I don’t recommend using chemicals.  The primary reason is that I’m an organic gardener.  But even if I weren’t, I’d choose not to use any, because bindweed grows in close proximity to my perennials—sometimes even in the midst of a clump—and I would risk killing them along with the bindweed.

A flower stem caught in bindweed's grip

The answer to control and eradication is patience, persistence, and vigilance.  When I discover that bindweed has already begun to cover a plant in my garden, I reach for my trusty kitchen shears and do a bit of snipping.  I start at the top of the plant and work my way downward, snipping the vine every foot or so and gently pulling off each one-foot section as I go.  Sometimes the vine is so tightly bound around a stem that I have to snip every six inches or less.

As I reach the lower part of the plant, I follow the vine to where it emerges from the ground.  (That location is not always obvious in a densely planted bed.)  I use a garden shovel to carefully excavate as much of the rhizome as I can.  It’s generally impossible to get out the whole rhizome, so I have to settle for as much as I can dig up without harming other plants in its vicinity.  Before replacing the soil, I carefully check it to make sure that no stray bits of rhizome have been left behind.

A sturdy kitchen shears is a handy tool for all kinds of gardening tasks.

All the excavated rhizome pieces go into a container separate from the sections of vine I’ve cut.  I either burn the pieces in our outdoor fireplace or, if there are only a few bits of rhizome, I dump them on a concrete surface and crush them with my foot.  The latter method is definitely the more rewarding one!  The cut vine sections go on the compost pile along with the rest of our garden refuse.  It’s important to inspect the vines for any seed pods before composting them.  The last thing you want is bindweed growing in your compost pile.

Now comes the hard part.  It takes at least three years to rid a bed of bindweed.  This is where the gardener must practice patience, persistence, and vigilance.  All sites where a vine has emerged must be marked with some durable material so that they can be monitored.  Monitoring should start about two weeks after digging out the rhizome sections.  As soon as a new vine emerges, it must be dug out and treated in the manner described above.  Check all marked sites every two weeks during the growing season.  The object is to deprive the roots and rhizomes of the energy generated by the leafy vines, eventually starving them to death.

Bindweed in an Iowa cornfield

It’s important to make a special effort to search for emerging vines in all your beds in early spring.  They’re easiest to spot when the plants in a bed are still small and further apart.

I can attest to the fact that the method I’ve described actually works.  Three of my beds are now bindweed free after almost four years of vigilance and action.  But I can’t let my guard down.  Since bindweed grows all over the nearby countryside, there’s always a chance that a bird might deposit a seed in those beds.  And then I’ll have to start the process all over again.

Bindweed photos are courtesy of Iowa State University Extension and Outreach.