There’s a new report out from University of Copenhagen on killing weeds between paving stones. What they recommend is burning or steaming the weeds lightly and repeatedly. Boiling water, steam, even flamers can be used to wilt the leaves over the course of several treatments (six was recommended). This process damages the leaves beyond repair, slowly starving the roots to death.
I’m not sure exactly how I feel about this study (which is getting a lot of attention on the internet). On one hand, it is a chemical-free way to kill weeds…but on the other hand, it’s pretty labor intensive and requires energy inputs for generating heat. Moreover, what does one do once those weeds are gone? Those bare patches of sterilized soil are just going to be recolonized by new weeds.
Several years ago I had a Master’s student look at different methods of killing English ivy. She also tried the steam treatment. Ivy laughs at steam. Aggressive perennial weeds like English ivy or blackberry or Japanese knotweed are unlikely to be much affected by blanching, and certainly not by half a dozen treatments.
But most of us probably don’t have big, woody-rooted weeds amongst our paving stones. In my own garden, it’s a mixture of species that fill these gaps and some of them – like mosses and some smaller ferns – I actually enjoy. So I pull out the things I don’t like, leaving the desirable species to fill in the gaps. It’s simple and requires no special equipment.
Am I missing something here, or is this really much ado about nothing?