In the chapter on mosses, Mosses and lichen, we have a section named Unwanted mosses and that is where this post is about. The unwanted moss here is Hypnum cupressiforme (Dutch: Gesnaveld klauwtjesmos), and Hygrohypnum luridum (Hygrohypnum Moss, Drab Brook-moss, Dutch Gewoon spatwatermos).
These mosses are very strong growers and survivors. When they first show up you could easily be tempted to let it go. It is green and it is a groundcover so what ? Well be assured that eventually the mosses will overgrow your groundcovers, spread throughout the garden getting uncontrollable and no longer show a fancy look.
The mosses have creeping stems which form smooth, dense mats that are in first instance hard to remove from under the groundcover and late will cover your groundcover and probably kill it.
In Unwanted moss removal you find a slide-show that gives an impression of some of the moss removal activities and measures we have taken in the past.
In the whole Tsubo-en garden Leptinella potentillina or squalida (prev. Cotula common name:“Water buttons” or “Buttonweeds”, Green Brass Buttons, is the primary “moss substitute” groundcover.
In the area’s where the Cotula gets higher few mosses will develop, it is only in the more sunny and higher situated area’s where mosses show up and sometimes overgrow the groundcover.
A big mistake was to cover the Leptinella groundcover and of course the unwanted moss, with a thin layer of soil. This was done under the assumption that the moss would die and the groundcover would take over control. This did not happen. Instead the moss found an even more solid protection just under the ground to later pop-up even more aggressively.
If the moss has grown to a high density and even overgrows the groundcover, it may take upto 2 or 3 hours per square meter to remove most of it. It is never possible to remove it al. See my note about squatting on the bottom of the post: Razor-sharp thyme edges.
This year we have removed most unwanted mosses in the groundcover in this manual way. A small part remains to do, that is too dense. This will get removed the chemical way that I will discuss in a later post at the time of execution.