I came across an old publication about dealing with weeds in farm and garden situations. The author discussed why weeds grow where they do and how we can use that knowledge to reduce weeds naturally without the use of herbicides. Needless to say, that is a large and complex topic, too big to go into detail here.
One item that did jump out at me was a unique way of killing field bindweed.
Field bindweed is one of the most tenacious weeds we have in the garden. If you have ever had a bindweed infestation in your garden, you know what I’m talking about. It grows from a net work of underground roots that will grow several feet deep and have a lifetime of twenty years or more. I’ve blogged about this weed in the past.
Other than using chemical herbicides, the traditional way of controlling bindweed is to starve the root system by cutting back the tops whenever you see them. That may mean as often as every few days or so, especially early in the season. By cutting back the tops, you remove the leaves stopping all photosynthesis. That forces the plant to use stored energy as it sends up new shoots. Eventually, the plant runs out of energy and dies. That process may take a few years.
The author of the weed publication offers a different take on bindweed. He mentions, almost in passing, that dahlia roots secrete a substance that kills field bindweed. I’ve been trying to think back to all of the hundreds or even thousands of dahlias I’ve grown in the past and can’t seem to recall ever seeing bindweed growing with dahlias. I’m not growing dahlias this year and have not grown them for several years.
If the dahlia vs bindweed theory is true, that gives gardeners a new ally against this noxious weed. It would mean taking a piece of ground out of normal production and growing dahlias there for a season, which would not be all that bad of a thing I suppose.
Growing enough dahlias to cover a large area presents a whole new set of challenges. That is a topic for another time.