Colorado Mountain Gardener

Posted: 26 Jul 2019 08:03 AM PDT

by Vicky Barney

Before I found it in my garden, I thought field bindweed (Convolvulus arvensis var. linearifoliu) was a rather pretty plant.  It looks like a morning glory (in the Convolvulus family), growing along the ground or as a vine, and producing pretty white or pink flowers.  But unlike Morning glory, it grows extremely quickly, takes over gardens and lawns, returns year after year, and is nearly impossible to eradicate. 

Field bindweed can be distinguished from morning glory by its arrowhead-shaped leaves and its ability to grow in nearly any environment – in yards, along roads, in pastures.  One plant will grow an extensive underground root system that may travel 10 feet deep and contain a 2-3 year food supply.  It will produce up to 300 seeds that stay viable in the soil for 40 years.  And it cannot be dug out easily – the stems are fragile and any root piece left in the soil will produce a new plant.

Because of the tenacity and invasive nature of this non-native, the Colorado Noxious Weed Act has identified field bindweed as a “List C” species, which means local government may require it be contained, eradicated, or suppressed.  It may never be completely eradicated in our gardens, but it can be contained and suppressed if we are consistent with healthy gardening practices.

Vigilance – Look for bindweed when weeding or after introducing new soil or new plants into your yard. (My bindweed arrived in the soil of a nursery-grown shrub.) Young seedlings can be removed if roots are dug several inches below the soil.   Established plants should be cut or pulled at the surface as soon as possible, stressing the plant and slowing its growth.

Mulch – Bindweed grows best in the sunshine.  Mulching regularly will discourage growth.

Healthy Soil – Improving the nutrient balance of your soil will discourage most weeds.  A soil test will determine the necessary steps to soil health specific to your yard. (https://webdoc.agsci.colostate.edu/soiltestinglab/soilsample_horticulture.pdf)

For large dry land infestations of field bindweed, a biological control is available.  CSU’s Plant Talk 1493 has more details on using the bindweed mite. (https://planttalk.colostate.edu/topics/insects-diseases/1493-bindweed-mites/)

CSU’s Plant Talk: Controlling Bindweed (https://planttalk.colostate.edu/topics/weeds-cultural-problems/2104-controlling-bindweed/) includes a discussion of using herbicides.  Like the controls listed above, this method requires several years of vigilance.  It also requires careful application to minimize damage to surrounding life.  It is not an option for those of us cultivating wildlife-friendly yards.

Perseverance and healthy gardening practices will discourage nuisance weeds like field bindweed.  Fortunately, these same routines will keep our gardens flourishing.

Vicky Barney gardens for wildlife and is a member of the Master Gardener Class of 2011.