As Sydney has experienced much rain from late summer into mid autumn, moss is looking prematurely green. With our usual late summer heat it would be still relatively unattractive. Perhaps at this time; moss information will be quite timely.

Here are my responses to some of the statements I have heard people make:

1. "The moss on my Bonsai has died ".
   The appearance of brown or dry / lifeless moss is the effect of summer dormancy. Increased light intensity, excessive heat, surface dryness or longer day-length causes this condition.
   
   
2. "I don’t know why my bonsai has died because the moss is so green ".
   Moss is not an indicator of the moisture content of the ‘soil’ mix, so when the moss goes to sleep, the owner panics, and in an effort to ‘save’ the bonsai applies too much water. Unfortunately the bonsai becomes waterlogged and subsequently succumbs to root rot.
   
   
3. "My moss has turned to black jelly".
   Nitrogenous fertiliser applied liberally; will act upon moss, killing it and reducing it to a black slime.

This tip is about moss & other surface effects for bonsai.

Moss starts awakening from its summer dormancy when the days become shorter either by seasonal factors or reduced light from too frequent cloudy days. This is another indication that winter is nigh.

Moss becomes invigorated by cooler weather, coupled with moister conditions. There may not be increased rain, but moisture, through capillary action rising from down-under at night creates a moist environment.

When collecting moss be careful that as little soil as possible is taken. If it is advisable to ‘dig’ a thick clod of earth with it, wash or skim it away before ‘planting’ thus avoiding creating an impenetrable surface. A blanket effect develops after a few years and it is beneficial for the plant to lift off the moss & literally roll it out replacing it more sparingly. Thick moss repels moisture instead of penetrating to the root system. Another advantage of rolling it out is that you will have an increased supply available.

Autumn through spring is the active growing time for moss. The earlier it is planted, the better its adhesion to the ‘soil’ by the time its growing ceases.

It is a fallacy that moss robs the plant of nutrition. Its energy comes from photosynthesis which means that weed-killers – Zero or Roundup TM. Active ingredient - glysophate can be sprayed or brushed on weeds without harm to the moss.

Moss can be selectively used to enhance surfacing by not covering the entire surface of a bonsai.

Continuing with bonsai surface effects also includes the not so desirable ground covers. Top of the list would have to be Liverwort. Although attractive, because of its wide flat plant body (thallus) that overlaps and covers the surface, limits the exchange of air & water to the plant. In other words it smothers the plant.

Innumerable thread-like roots (rhizoid) which create a blanket effect also cause an aeration problem; anchor the plant firmly to the surface. The mix can stay wet far to long, encouraging more rapid expansion of the pest. Conversely, water is shed from the surface without penetrating down. New plants explode even by the minutest pieces that have been dislodged and spores are dispersed by wind and water.

A slow & tedious method of removing it is to use tweezers to carefully penetrate beneath the thallus ‘plates’ and lift the whole section. The problem is to make sure nothing remains. Painting with vinegar works but can look unsightly when it becomes a dark jelly ‘blob’. Glysophate (Zero. Roundup TM.) Painted on at recommended strength will kill. It is advisable to use with a dye for obvious reasons.

To pick out a patch from a mossy area can create a bare section by the amount of fibrous threads, in which case the use of the above is less obvious. It is very difficult to ‘lift’ from rock, roots or trunk again the above solution is advisable.