Why all gardeners should learn to love moss
On Gardeners’ Question Time at this time of year, we get many questions concerning moss – mainly as a problem in lawns. Recently, with wet winters, moss seems to be getting the upper hand. So, as many gardeners are dramatically changing their mindset when it comes to lawns, are we going to reappraise the benefits of moss, too? Should we really be purging our lawns of this emerald invader?
There are more than a thousand different species of moss in the UK, and according to my neighbour Jon Graham, who is an ecologist and notable moss expert, because of the range of types, you can find a species of moss to suit pretty much any conditions.
When I was working in Hokkaido in Japan, I visited countless beautiful gardens where moss featured heavily, with verdant swathes of moss carpets, moss walls and water features laden with moss. Moss cushions cover tiny urban gardens, as they also cover the floors of woodland glades. When you view Chelsea show gardens created by notable Japanese horticulturalists, you see houses clad with mosses, and even beds (for sleeping) made of them, as well as splendid moss creations carpeting paths and walls.
In the UK, though, we are mainly concerned with killing it. When I asked Jon the best way to get rid of it, he was, not surprisingly, shocked. He pointed out that moss is teeming with biota (mini plants and animals living in it) that we are pretty much unaware of, but which are an important part of the ecosystem. It is a fantastic carbon sink too.
Apparently half a sq m of moss can absorb a kg of carbon dioxide: a staggeringly high amount, partly due to the surface area of moss being 30 times its size. “Trees” made of moss are starting to be created in cities, as it absorbs particles and pollutants, too. Moss also cools the environment, because its structure is like a sponge, sopping up moisture and then cooling the atmosphere as it evaporates.
The founders of German-based company Green City Solutions, which has pioneered these “trees”, point out that in addition to binding CO2, moss filters numerous other gases and substances that harm the climate. One of these is soot (“black carbon”), which has an effect on global warming that is up to 1,500 times greater than that of CO2. Mosses filter such soot particles, which are present in the air as fine dust. They reckon a CityTree moss filter offsets up to 355kg of CO2 and CO2 equivalents per year, making it an effective climate-protection measure.
Maybe the sea change that is happening here in the UK with lawns – ie forgetting the spraying and fertilising regimes to allow monocultures of fine grasses, and relaxing our approach to allow a richer mix of broad leaves within the grass – should also start to encompass a new appreciation of moss, as we realise what a fabulous resource it is to encourage. King Charles uses the term “mown green spaces” for his lawns. He relishes the fact that they are teeming with carpeting thymes, selfheal, many other broadleaves and moss, and so they rarely go brown in the summer as a result.
At Highgrove, the King has developed a small moss lawn. The method used was fairly laborious, in that all the grass was removed and a plastic sheet was spread on the soil, then covered with capillary matting and a fine compost spread. Mosses of various types (including from the Birkhall Estate) were then planted on this. This small moss lawn is high maintenance; it is weeded and watered in dry periods.
Jon advocates a different method, which is highly effective. He has planted moss around the edge of his artificial wildlife pool, by lifting 2p piece-sized bits of moss that thrive in similar conditions locally and then popping them into place, planting them very shallowly. From his tiny initial bit he now has a beautiful one-metre strip about 20cm wide around the edge. Jon advises that when you are collecting moss, make sure you have the landowner’s permission, that it is not a protected site, and that the moss is not a rare, scheduled bryophyte (the chances of the latter are very rare though).
When Jon is transplanting moss he sometimes just lifts it from a wall or similar with a knife and then plants it (if on soil) in place, or sticks it (if on to a stone) using a glue such as Copydex or Super Glue: you just need a tiny spot, as the moss has no roots as such and draws moisture from the atmosphere... The microclimate moss appreciates is just around a few square metres immediately around the plant, so when selecting your moss, try to match the new microclimate to the one it is being moved from. For Jon’s pool edge, the moss has bits of grass growing in it and it is designed to be natural and relaxed in appearance.
If you want to go down the instant route, you can buy 10 different types of moss (for varying conditions) from Moss Clerks. Claire Page and Marcin Ruta started the company and the variety of moss they sell is selected to thrive in a range of different light and moisture levels, soil conditions and humidity. They sell it by the square metre from around £79. It comes on a non-woven geotextile membrane, which is laid down on the earth. The soil doesn’t have to be weed-free as the membrane suppresses the competition. They collect the moss from forests that are about to be felled.
There are many ways to enjoy moss in the garden. At Highgrove there is a stone water feature in the walled kitchen garden. This was protectively wrapped in winter as the stone is not durable, until it was noticed that the bees sat on the moss on the water feature (they come out in winter intermittently) to drink. Now it is left uncovered, so the bees can use it all year round.
I had not realised that we have naturally occurring tufa stone here and that mosses are associated with its formation. They partially contribute to it as they rot down and their petrified stem deposits build up within it. Jon sent me a photograph of a locally occurring area where this has taken place. You could mimic this effect by creating a moss wall with water dribbling down the front of it.
A simple metal pipe can be effective and the walling could be weathered quite rapidly by attaching mosses to the stonework. When we made the Wind in the Willows garden for the Chelsea Flower Show almost 30 years ago, we cheated by bringing in moss-clad stones, which we carefully laid in the wall to give an instant aged effect.
There are so many ways to include moss in your garden: perhaps, for example, a pure moss shed roof, on which you could colonise moss with capillary matting, which absorbs high amounts of water. A stumpery can be eye-catching, and hunting down the elements and making it is satisfying. I love brick or stone paving with all the joints picked out in that characteristic, almost luminous green of velvety moss.
Watch my latest YouTube video: ‘Sterling Moss – great ways to grow it, use it or lose it’
‘The Magical World of Moss Gardening’ by Annie Martin published by Timber Press, £15