Updated/Fact-Chacked on July 14, 2023 by Gareth James
Picture this: it’s a lazy Sunday afternoon. You’re lounging on your patio, a steaming cup of tea in hand, surrounded by your loved ones. The sun is shining; the breeze is just right – moments like these make all your hard work worthwhile.
But as you look around, a certain something catches your eye. Amid the natural beauty of your patio are unwelcome guests, dotting the landscape with stubborn black spots – the dreaded black lichen.
Despite your best efforts to maintain a clean, inviting space, these pesky invaders persist, challenging even the most diligent cleaners among us.
However, fear not! You’re about to unlock the secrets of eradicating these stubborn blights from your favourite outdoor space.
What is Black Lichen?
Lichen is a unique and fascinating life form that results from a symbiotic partnership between fungi and algae or cyanobacteria.
This cooperative living arrangement enables them to survive in some of the harshest environments on earth, from arctic tundra to scorching deserts and rocky cliffs to your backyard patio. Lichen takes on many forms – from flat, crusty patches to leafy fronds or bushy tufts – and can range in colour from bright oranges and yellows to more subtle greys and blacks.
However, they’re not just tough; they’re also slow growers, often taking many years to reach the size of just a few centimetres. Despite their intricate biology and survival skills, black lichen can be an unsightly nuisance that we are eager to remove when it comes to our homes and outdoor living spaces.
- Common lichen growing on a tree
Difference between Moss and Lichen on Patios
While moss and lichen can present aesthetic challenges to your patio, they are distinct and the conditions they thrive in.
Moss, a soft, green, carpet-like plant, prefers damp, shaded areas, often growing in patches where sunlight is limited and moisture abundant. It tends to grow thicker and can even damage surfaces by trapping moisture underneath. My north-facing patio suffers terribly from moss between the pavings, and I’m constantly testing new products.
On the other hand, lichen – our focus here – consists of crusty patches or branching structures that are usually grey, white, or black. Lichen is hardier and can withstand more sunlight and dryer conditions than moss. It adheres strongly to surfaces, and its black variety often leaves stubborn spots that are harder to remove, giving patios a speckled, less polished appearance.
How to Get Rid of Lichen
Believe it or not, you can treat your patio with something available, cheap, and effective: bleach or the stronger compound, sodium hypochlorite.
However, you have to be careful with bleach because when hosed down in surface runoff, it can kill any plants or greenery with which it comes in contact. If there is a runoff, wet the plants before and after the bleach treatment to minimize the damage. You have to protect yourself while using bleach, as well.
You can buy a dedicated black lichen removal product, I recommend Wet & Forget’s product below:
What You Need:
- Sprayer/watering can
- Safety goggles
- Face mask
- Safety boots
- Old clothes
- Scrubbing brush
What You Need to Do
- Declutter your patio to make way for the cleanup. If any greenery is nearby, protect it by covering or blocking it from the paved area of concern.
- Sweep the whole patio to remove any leaves, debris, or loose dirt. Pull any weeds that you may find on the way.
- Wet the whole patio, not just the affected area, with clean water to prepare it for the cleanup, and don’t forget the corners. This would be a suitable time for you to wear your safety clothes because you don’t want the bleach to touch your skin, eyes, or respiratory system.
- For a 1:9 solution, mix 1 part bleach and 9 parts cold water in a sprayer or watering can. You can dilute or strengthen the solution depending on your needs and the severity of the problem, but this ratio will most likely work.
- Apply the diluted bleach solution to the whole patio, not just the affected areas, and brush it well. Again, don’t forget the corners. Leave it for 30 minutes to work its magic.
- Rinse the whole area with clean water. You can brush again while rinsing for extra spotlessness.
- Enjoy the results of your hard work!
You deserve an outdoor area that is free from any hideous black spots that ruin the scene. If you follow the cleanup tips above, you won’t have to worry about these organisms ever again.
Removing black lichen FAQS
- What is black lichen?
Black lichen is a type of symbiotic organism that consists of fungi and algae or cyanobacteria. Its dark colouration characterizes it and often forms tough, stubborn spots on outdoor surfaces like patios, walls, or fences.
- What is the scientific name for black lichen?
The term “black lichen” can refer to several species, but a common type often found causing unsightly spots on patios is Ophioparma ventosa.
- Should lichen be removed?
While lichen doesn’t typically cause direct harm to surfaces, it can make them appear unkempt and neglected. On porous surfaces, they can be harder to remove over time. So, for aesthetic reasons and easier maintenance, many homeowners prefer to remove lichen from their outdoor spaces.
- What does poisonous lichen look like?
Most lichens are harmless to humans, but a few, like the Wolf Lichen (Letharia vulpina) – known for its bright yellow-green colouration, can be toxic if ingested. However, poisonous lichens are not typically found in common residential areas.
- Why is lichen black?
Lichen can be in many colours, including black. The colour is generally due to the specific types of fungi and algae that make up the lichen and how they interact with each other and their environment. Black lichen might also contain certain pigments that protect from UV radiation.
- Is lichen good or bad?
Lichen is not inherently bad. It plays an important role in many ecosystems, aiding in soil formation and providing a source of food and shelter for various animals. However, when it grows on man-made surfaces such as patios, it can be considered a nuisance for aesthetic reasons.
- What are the 3 types of lichen?
Lichen can be generally categorized into three types: crustose (forms a thin crust tightly attached to the substrate), foliose (leafy in appearance and attached by small points), and fruticose (more complex, with a branched or bushy structure).
- Is lichen a fungal infection?
Lichen is not a fungal infection but rather a symbiotic relationship between a fungus and an alga or cyanobacterium. The fungus provides structure and protection for the photosynthetic partner, providing the fungus with nutrients. It’s a cooperative relationship rather than an infection.
Mary shares a passion for gardening with her husband John, though she is more focused on growing veg on their allotment at St. Margaret’s Allotments, Durham. Mary also works in the lawn care industry and manages the lawns for the Durham University campus.