War on Bryophytes – Moss

Bryophytes  and  Embryophytes are the botanical names given to mosses, lichen, liverworts, hornworts, molds, algae and slimes. These are what one could label primate plant-like forms which were the first land type plants on the planet, millions of years ago. It was as a result of these primitive plant forms that began the process of building soils from rocks split and powdered by the action of water and ice.

Members of this diverse plant family are found all over the world, many growing in places where no other types of plants could grow, so in a sense they are still creating growing conditions for higher plant forms to grow.

Many  bryophytes are very attractive with feather or fern like structures where others look more like something from a alien landscape.
When  bryophytes grow in places we do not want them to grow they become a nuisance  just like weeds.

Lichen and liverworts appear to be able to grow on most surfaces including glass, public footpaths, fences and roof tiles are favorite spots for them. Vertical glass is difficult for them but glass roofs of glasshouses are not.

Algae and mosses growing on paths make for a slippery condition when wet and dangerous to those that can occur serious injury if they slip and fall.

Lichens that colonise on the trunks and branches of plants and trees look unsightly and can lead to rots and losses.

Mosses growing in lawns are another bug bare,  not only making the lawn unsightly but also suffocating our preferred grasses.

More often than not, wherever  bryophytes appear, it means a war to eradicate and control. When action is not taken they prolificate, spreading out to cause more harm.
Bryophytes cannot be controlled easily by scrapping off, as residues will be left that allow them to re-stablish.

In lawns many resort to sulphate of iron to burn off mosses, which  is only a very temporary fix as the acidity of the iron only burns off the top of the moss, allowing it to re-establish again fairly quickly.

There are various products advertised to clean up bryophytes such as ones that are sprayed on, then left for weathering to remove. Many of these are fairly expensive and  bryophytes are like ants, you can never eradicate them as they will always come back .
Bryophytes multiply by spores of which they create vast numbers, carried by water and air they will always return.

Some years back a chemical called benzalkonium chloride, which was used in the medical industry for sterilizing instruments, was discovered to be a boon in the control of  bryophytes without harming other plants.

Benzalkonium chloride is an interesting chemical been an aqueous solution and used as a detergent, fungicide, bactericide, and spermicide. It is still widely used in mild solutions for eyewashes, hand and face washes, mouthwashes, spermicidal creams, and in various other cleaners, sanitizers, and disinfectants, though there are some concerns on its safety as it can be an irritant even in mild doses and very much so in stronger solutions.

The first product to use benzalkonium for the control of mosses etc was Surrender and the writer picked up on this many years ago and introduced its use to gardeners in Palmerston North though the garden centre I was operating at that time. It became very popular but was only available in the commercial pack of one litre.

I convinced Yates NZ to market the product for New Zealand gardeners, at which time it became available in 200 ml bottles. A ‘me-two’ product emerged with the same formulation called Yield and McGregors came out with  McGregors Yield Moss Control also in a 200 ml bottle at a more competitive price.

These proved very popular and effective resulting in other chemical controls on the market, for the home garden to disappear.

Over the following years these brands of the chemical  benzalkonium  have become fairly expensive leading to complaints from gardeners as to their cost effectiveness.

The products are formulated at 500g / litre benzalkonium chloride in the form of a soluble concentrate and used at the rates of  25 to 50 mls per litres of water making the 200 ml bottle only able to produce between  4 to 8 litres of spray.

Not a lot if you have a big area to cover and the need to re-apply when  the problems reappear.

Many mosses and liverworts need the 50 mls per litre dosage to have effective control where some other  bryophytes such as lichen and algae can be controlled successfully at rates of 10 to 20 mls per litre.

Unfortunately the strength of only 10 to 20 mls for lichen and algae information is not always made available and gardeners can waste product using unnecessarily at the higher rates on these easier to control  bryophytes.

A new product is now available from some garden centres using the same formulation and called Moss and Liverwort Control. Available in both 200 ml and 500 ml containers making it more affordable in comparison to the previous brands.

Another interesting aspect is that the chemical  benzalkonium chloride is a track able chemical by ERMA which does not affect the home garden market in quantities of up to 1 litre.

But if a gardener has in storage over 1 litre of the concentrate then they must by law have a handler’s licence.

This is obtained by sitting a one day agrichemical course and passing.
I congratulate ERMA in taking tighter controls on agricultural chemicals which is in the interest of us all and the environment.

The new regulations also means that more safety information must be on the labels of many chemicals, which should help users to be more careful while handling and using.

Moss and Liverwort Control’s labels has all the new requirements for safety which at first glance may give the user concerns about using the product. This is good in actual fact as more care is likely to be taken and a great advantage to the user as you would certainly not want to get a splash of the concentrate (or the diluted product) in your eyes.

The safety information for  500g / litre benzalkonium chloride is:
May cause an allergic skin reaction. Causes severe skin burns and eye damage.
May cause allergy or asthma symptoms or breathing difficulties if inhaled.
Toxic to terrestrial vertebrates. Toxic if swallowed.
WARNING: PRECAUTIONS: IF SWALLOWED: Rinse mouth. DO NOT induce vomiting. IF ON SKIN: Wash with plenty of soap and water. IF IN EYES: Rinse cautiously with water for several minutes. Store in original container, tightly closed, away from foodstuffs. When mixing wear a face shield and protective waterproof gloves and clothing. When spraying use protective clothing. Do not eat, drink or smoke while using. Wash hands and face before meals and after work. Toxic to aquatic organisms. Do not contaminate streams, rivers or waterways with the product or empty container. Disposal of Containers: Triple rinse empty container and add residue to spray tank. Burn the empty container if circumstances, especially wind direction permit. Otherwise bury in a landfill. Avoid contamination of any water supply with chemicals or empty container.
EMERGENCY RESPONSE (All Hours) 0800 243 622

By wearing rubber or latex gloves, gum boots, protective waterproof clothing, eye protection and a spraying mask while mixing with water and spraying should keep you nicely safe. One of the great advantages of this product is that you can safely spray it over other plants without harming them but to be sure of  this, it is advised that one should water the preferred plant’s foliage with the hose, 30 minutes after spraying. It only takes 30 minutes for Moss and Liverwort Control to get into the target bryophyte and do its job. If it rains or you water after that time the product will not be deactivated.

When using the product adjust your spray nozzle away from a mist to more of a jet as it needs a bit of force to get into the bryophyte. The product has a similar action to glyphosate (Roundup etc) as it goes right through the bryophyte killing the all of it and often making the target area difficult for re-establishment for sometime.
The product must not be mixed with other sprays to avoid chemical reactions but other sprays can be applied to the target area later. For instance if you have moss in a lawn; firstly spray with Moss and Liverwort Control and next day a lawn herbicide and Thatch Busta could be applied, mixed together. The Thatch Busta will also help clean up the material left behind by the dead moss.

Once sprayed and the area lightly watered 30 plus minutes later the re-entry of children, pets or wild life can be allowed. The product can be used indoors in the weaker solutions to control molds in showers, on the backs of curtains etc.
With the right knowledge and precautions applied, makes this product very efficient and safe to use.

2 comments on “War on Bryophytes – Moss

  1. P M Chew on said:

    i read with interest the article “war on
    bryophytes” by Wally Richards. i want to know if benzalkonium chloride on
    its own would be as effective as commercial brands which i assume are
    formulated with other addictives.what would be suitable addictives to
    enchance the efficacy of ben chloride? tq rgds pmchew

  2. Bryan Sellars on said:

    I just bought some One Step Spray and Walk Away this contains 99g per Lt of benzalkonium chloride.

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