Mosses and lichen

Although mosses are simple and rather primitive plants they are not easy to determinate nor easy to cultivate. And when they find their way often not easily eliminated. Mosses and lichen (Dutch: korstmos) offer a science on their own.
Moss is a very hardy plant. If the leaves dry out, plants are revived by soaking with water. Some can survive over hundreds of years.
When you want additional information on any of the mosses you can use the Latin or common name and go to the applicable website in the section Links related to moss and lichen at the bottom. Or just type in the name in you favorite search engine and see the results that in most cases will be plenty.
In Tsubo-en we have intentionally not planted any mosses as groundcover. This was a design requirement originating from prior experience. Most mosses that we do have, did grow there by natural causes. Not to elect for mosses as groundcover has two important reasons:

  1. The environmental and location conditions are not well suited for large area´s of moss. Most mosses like damp and/or shady locations and mostly demand firtile soil although there are even epiphyte types.
    As Tsubo-en is a very "open" garden there will be too much sunshine and breezing in weeds.
    In addition the soil is not suited for most mosses. We have pure sea-clay on this "new land". that is land that was taken from the sea in only the previous century, in the decade around 1942 (see: House and garden). Although mixed with compost, sand and garden mould, this is no substratum for the wanted mosses.
  2. This item has to do with the feasibility to preserve mosses.
    There are to many (black)birds that see it as a challenge to turn over and rip apart each and every square centimeter or inch of moss. This we know from experience in previous gardens.

    Although other birds may also be guilty the beautiful blackbird, a great flutist, too needs to find its food.
    As there is no way, nor will, to keep them out of the garden growing moss is impossible as the blackbird will rip apart and turn around each and every piece of it no matter how small and well hidden.

The above implies that ground covers are used as a replacement for mosses that would be used in a Japanese garden in Japan. In Japan the coveted "star moss" is Polytrichum juniperinum. To find out what replacements are used in Tsubo-en, please see the Groundcovers chapter.

When you start thinking about mosses, where you have them and want them and where and which ones are unwanted, you may be surprised of the number of mosses and places you come across. At least that was our experience.

In Tsubo-en we have many species of moss that can be subdivided into two types: Wanted and unwanted mosses.
To be more precise we should ad ..."on this spot". A moss may be wanted or even desired or required (think of achieving sabi and wabi) to cover a specific object or place, but the same moss may be unwanted on an other spot or object.

Wanted mosses

In this category we can differentiate between mosses that grow intentionally on a specific surface and those that are accepted and tolerated. This chapter addresses the intentionally growing specimen.

0710 As "groundcover" for bonsai mosses are indispensable. Sometimes a suitable moss just finds its way. More often we use the transplantation method to get a moss growing at the desired spot. Here Fissidens bryoides (Dutch: Gezoomd vedermos). Here growing under our oldest bonsai oak, Quercus robur.
A number of objects if not require than at least they desire to be covered with mosses or lichen to get sabi proparties.

This is the chouzubachi of the main garden tsukubai facility.
The "mosses" here are very much lichen and algae.
2224 The same that is stated for the chouzubachi is true for the hakamazuri-ishi or tsukubai-ishi (also mae-ishi) as the front step stone.
This stone has a metal version of the "coin" as described for the front garden tsukubai, chiselt in as an inlay.
In this natural stone terace, named "hidden terace", located near the water front, moss is a higly desired groundcover filling the joints.

This is moss that grows naturaly in the garden and the surounding.
2207 This photo shows a close-up of some hidden terace joints filled with moss.
This (most probably) is Fissidens taxifolius Hedw. (Dutch: Kleivedermos), native to the vicinity.
The same species can be found in the path joints.

Although the growth started by natural causes we give it a hand to survive and get even better.

This is hard to do as it is a war against the blackbirds.

Worm-holes are yet an other concern.
Not sure yet iwheter this is a moss or a lichen. Whichever it is it adds to being sabi. 2233
This also is Fissidens taxifolius Hedw. (Dutch: Kleivedermos), native to the vicinity. 2232
2222 This shows our raihaiseki that lays in the main garden ginshanada.

It is a large flat natural stone, now fully overgrown with a thin layer of lichen (moss). Actually this is number of different yet unidentified lichen.
This photo shows the "head" of the "turtle island" in the front garden. It has a had of crustose lichen.

This (most probably) is Caloplaca flavescens (Hudson) J.R. Laundon (Dutch: Gelobde citroenkorst).
Easily confused with C. aurantia and C. decipiens, C. thallincola or Candelariella medians.

It also grows on our roof tiles where it is unwanted !

Accepted or tolerated mosses

This are the unintentionally growing mosses that are accepted or tolerated, that is growth of mosses in the sense of "don't mind" or "won't harm".

These can be mosses that grow in between ground covers, e.g. on tsukiyama grounds, or solitary growing mosses and lichen.

In the center we see moss that just grows there. This is the same moss that we find in the path joints as described above. Fissidens taxifolius Hedw. (Dutch: Kleivedermos), native to the vicinity.

The originally planted groundcover did not grow well.
At the bottom that is growing just fine, Leptinella minor (prev. Cotula).

At the top we have yet another groundcover that performs great and grows in from the area under our Pinus densiflora, Japanese Red Pine (Me-matsu). This is Thyme, Thymus praecox "minor" that forms a great low-maintenance carpet.

To us this combination is just fine. May the strongest survive.

Fissidens incurvus Röhl (Dutch: Gekromd vedermos) here growing uninvited on the garden-wall stones. We are glad it does and leave it there. 2215
2226 Moss living in harmony with our primary moss-replacement, Leptinella potentillina (prev. Cotula). Mostly the Cotula looks better. This is a very dry and sunny spot. The moss nevertheless likes it !
Fissidens taxifolius Hedw. (Dutch: Kleivedermos) again. Now growing solitary at a tobi-ishi step stone. This is "won't harm" situation and even ads to the sabi experience. If it gets too invasive it needs to be thinned out. 2221
2214 Lichen Caloplaca flavescens (Hudson) J.R. Laundon (Dutch: Gelobde citroenkorst) growing on a step stone.

This is only just acceptable as it can get very slippery. This needs to be watched closely.

Unwanted mosses

Most mosses are perennial and can be very invasive. Below we give an impression of most of the "problem" mosses in Tsubo-en. Some of them keep us very busy.

2201 Our greatest enemies are Hypnum cupressiforme, cypress-leaved plait-moss (Dutch: Gewoon of Gesnaveld klauwtjesmos) and Hypnum jutlandicum (Dutch: Heideklauwtjesmos) and Hygrohypnum luridum (Dutch: Gewoon spatwatermos), the first and last ones being the most widely occurring.

To the left it tries to overgrow the Thyme groundcover, Thymus praecox "minor".
Although this forms a very tight carpet it manages to get trough.
If we let it go, the moss Hygrohypnum luridum and Hypnum cupressiforme would easily take over our main groundcover Leptinella potentillina (prev. Cotula).

It looks fresher green and shows less seasonal coloration than the Cotula that it overgrows in winter.
2202 Hygrohypnum luridum is also well settled on the ground under the Buxus and inbetween the Cotoneaster dammeri.
Our second strongest enemy is Marchantia polymorpha, common liverwort, (Dutch: Parapluutjesmos). It can be found in every crack and corner on the soil.

Here it is found under the Buxus.
2211 A major problem with Marchantia polymorpha, common liverwort, is the fact that it will not only grow in the joints but also over it and would eventually cover the pathways.

It also overgrows the wanted and accepted mosses.
An other example of Hypnum cupressiforme, cypress-leaved plait-moss and Hygrohypnum luridum (Hygrohypnum Moss). 2209
2218 As you can see Hypnum cupressiforme, cypress-leaved plait-moss and Hygrohypnum luridum (Hygrohypnum Moss), are not at all demanding and will just grow everywhere as long as they get some moist. Here in the gravel of the ginshanada.
Not moss but we wanted to give these a place. In most places fungus and mushroom are unwanted. 2219
2225 On the profiled Bangkirai wood (Shorea) used for the veranda we also can not allow mosses, lichen and algae to grow.

Mosses examples

We do not have authentic subject examples dedicated to and specific of this subject.
Nonetheless examples are available in a number of other "examples" sections. Most relevant: For the complete "visual" examples see the applicable framed-list in: Visual Table of Contents.

Lessons learned and what did not work well

Here we document what went wrong with regard to the groundcovers that we used or wanted to use.

  1. After about four year we started getting unwanted moss (cypress-leaved plait-moss or hypnum moss) in the Cotula groundcover, mostly on the higher tsukiyama grounds in full Sun area´s, where the Leptinella remains lower.
    Initially we did not regard this as a problem. However we should have started getting rid if it right from the beginning. After some six year it got to well established and now it takes a lot of effort to keep it under control.

    An additional difficulty here is the fact that in the beginning it will not always be obvious if the moss is wanted or unwanted.
    In case of doubt the adagio is: elimination.
  2. Although more a maintenance-hint we want to list it here. An easy way to remove algae and mosses from the veranda wood, or to at least keep control of them, is to spray it with household vinegar. Only do this when you do not expect rain for at least a couple of days. Then let the vinegar do its job for a couple of days and when the algae has died broom it away with a rough broom.

    Note: This will also work to get rid of lichen from the roof-tiles and other places unwanted.

For the enthusiast we have added some links.

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