Posted on: January 4, 2009 Posted by: Nicole Harding Comments: 2

Lichen may look like plants, but they are actually a combination of fungi and plants that depend on each other to survive and multiply. They appear like plants or moss, or even like tiny coral formations. They can also survive harsh environments, extreme temperatures, long droughts or even saline conditions. Some lichen cannot survive with pollution, hence lichen can be rarely found in cities or urban areas. They can be found on trees, and although they prefer stressed trees, don’t do any actual harm. They can also grow on other materials like rocks, woody debris, soil, fence posts, rusty metal and sand. Lichen can even survive in space.

Lichen can be very unsightly and may cause slippery accidents, so despite being an indicator that the area you’re living in is pollution-free, it may be time to get rid of them. It may also harbor some nasty diseases that can affect you. If the lichen grows in hard-to-reach areas like your rooftops or your ceilings, make sure that you observe all safety precautions before attempting to get rid of them, or hire a professional roofer.

If you’re cleaning gravestones or material you would like to preserve, check if the solution that you wish to use is safe on stone or marble. Using solutions instead of water can cause staining and other sorts of damage to the gravestone.

Also note that there are still no proven chemical ways to getting rid of lichen, so be prepared to do the suggested methods continuously over a period of time before completely getting rid of them.

Lichen Removal and Control Methods

  • Brush them off. Get a scrubbing brush and water to gently brush the lichen off. For smaller areas, you can use a toothbrush with a bleach solution. Always use a soft-bristle brush as not to damage the surface where the lichen clings.
  • Scraping by. Use a plastic or wooden blade or scraper to scrape off the lichen gently. You can also use moss scrapers, which can be affixed on top of a vacuum cleaner or a blower. Moss scrapers are available in hardware stores.
  • Shade-y business. Lichen needs sunlight to live, so if the lichen is growing on something that is not fixed to its place (like a tree), you can transfer it to a shady place where sunlight won’t reach it. This is usually done for bonsai trees with lichen growing on them. If you are dealing with lichen growing on something that IS fixed, use a shade cloth to cover that particular area to deprive them of their light.
  • Blast off. If you have a high-pressure hose or a pressure washer, you can use this to blast the lichen off the surfaces.
  • Toothbrush them away. For smaller areas of lichen growth, you can use a toothbrush and a bleaching solution to gently brush the lichen off.
  • Be specific. There are products in the market that are specifically used for removing lichen. Visit and inquire at your nearest home and gardening store about these products. Some examples are HT-777 Marble Poultice, Orgo Clean and Bio-Lichen Off.
  • Non-ionic cleaners. You can use non-ionic cleaners or detergents. Mix it with water and gently scrub the lichen away.
  • Bleaching. To make the mentioned methods of using water more potent, mix a quart of bleach to two gallons of water for spraying. For smaller amounts, keep in mind that the bleach must be one to ten parts water. You can either spray or use this as your brushing solution.
  • Lime Sulfur. Lime sulfur is typically used against fungi growing on trees, which also includes lichen. They are usually sold ready to be used in most gardening stores. Be careful in using this because lime sulfur has a strong smell and can burn your skin. For deciduous trees, or trees that shed leaves seasonally, spray it on during the winter season when the trees are bare. For evergreens, or plants that have leaves all year round, dilute the lime sulfur even more with water, and use a brush to gently brush the lichen away. Another word of caution: Lime sulfur can also cause stains and leaf drop if applied to the wrong places like roots or leaves.
  • Cloudy ammonia. Remember to wear rubber gloves and eye protection when using cloudy ammonia for getting rid of lichen. You can also use a mask because ammonia can irritate your nose. Mix cloudy ammonia (ammonia with soap) to ten parts water. Using a sponge, apply the solution all over the surface and leave it there for 24 hours to kill off the lichen. Come back the next day, soak the affected area with water and brush it using a stiff brush and elbow grease. If there’s still lichen left, repeat the process. Don’t mix ammonia with bleach, as it will produce a toxic smoke that can cause permanent damage to your lungs.
  • Chlorine and water solution. Using a chlorine and water solution is also effective against lichen and requires minimal rinsing afterwards. However, it is toxic to people and plants, so make sure you take all safety precautions while using it.
  • Sodium hydroxide. Although considered safer for landscaping uses, sodium hydroxide, like the chlorine and water solution, should be used with care and precaution as it is toxic and caustic.
  • Zinc strip. If lichen grows on your tiles, install zinc strips. It may take a while before it works and takes out the lichen, but it’s effective. If the lichen has already grown, remove it first before installing the zinc strips on your tile caps to prevent them from coming back.

Some lichen are actually endangered species and are still an integral part of our environment. If you think you can still live with your lichen and do not have much contact with them, you can leave them alone. Otherwise, just be sure to take all precautions when using your chemical of choice when removing lichens to have a cleaner-looking house and lawn.

Click here for more information on how to get rid of lichen.

2 People reacted on this

  1. Under the ‘Bleaching” heading you specify a solution of one quart of bleach to two gallons of water, a ratio of 1:8, and in the next breath you quote a ratio of 1:10. Which is it?

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