Digging or pulling the horsetail out is not practical. It is impossible to get all the roots — any bits left will continue to grow. The best approach is to keep snipping of any shoots it sends up. That depletes the roots of energy, eventually doing them in.
If you happen to be by the planter and see some horsetail, help us out and cut off any shoots!
|Horsetail hiding under some grasses|
Also, remember that we can use help watering, too!