Most gardeners are all too familiar with bindweed, a member of the morning glory family. With its white to pink vase-shaped flowers and elongated green leaves, it spreads its twisting vines across areas of disturbed soil, such as vegetable gardens and flower beds. The more the gardener tries to pull it out, the more it spreads. Reproduction is by seed, which can remain viable in the soil for up to 50 years, and creeping rhizomes, which may extend up to 6 feet from the mother plant.
If that doesn’t scare you, consider that established plants have a taproot that can extend 20 feet below the soil surface, and lateral roots that grow 30 feet long! This root system stores enough food to keep the plant alive for three years, even if the area above it is paved over. Repeated applications of herbicides may not kill those roots. Once an area is covered by bindweed, it is almost impossible for native plants (or anything else) to become established.
It’s easiest to control bindweed before it completely takes over. Hand-pulling seedlings works until the roots become established. Removing all top growth for several years will eventually starve the plant. So will several years’ darkness. You can also let the sun do the work. Called solarization, the idea is to bake any seeds and seedlings. You cover the infested area with clear plastic, so that sunlight raises ground temperatures to lethal levels. This is best done in mid-summer, when sunlight is at its strongest.
For homeowners, two chemical weapons are available: 2, 4-D,and glyphosate (sold under brand-names such as Roundup, etc.). Glyphosate will kill everything it touches (except, apparently, the target bindweed) while 2,4-D only kills broad-leafed plants, making it safe to use in lawns. Apply these herbicides three times during the growing season (spring, summer, and fall) to “suppress” the weed. Don’t expect to completely eradicate it.
There is some hope for a biological control. The Bindweed Gall Mite (Aceria malherbae) is still being studied, but early results are somewhat encouraging. Research has also begun on the bindweed moth (Tyta luctuosa).
Bindweed is on Colorado’s Noxious Weed List “C,” meaning it’s illegal to grow it, we should try to control it on our property, but it’s pretty much hopeless.
I’ve heard pundits claim that the ultimate survivors on earth will be cockroaches. I think those roaches will have bindweed for company.