What Are Those Gray Patches on My Tree? Understanding Lichens and What They Mean for Your Landscape

If you’ve ever noticed crusty gray, green, or bluish patches on your tree trunks or branches, you’re not alone — and you’re likely looking at something called lichens. As a trusted lawn and landscape care provider, Rich Green Lawns is here to help you understand what lichens are, what they mean for your trees, and whether you need to take action. 

What Are Lichens? 

Lichens are a fascinating combination of fungus and algae living together in a symbiotic relationship. They attach themselves to surfaces like tree bark, rocks, or even soil. Despite their odd, flaky appearance, lichens are not harmful to your trees. 

They don't feed on the tree or cause decay — they simply use the bark as a home base. 

Why Do Lichens Grow on Trees? 

Lichens tend to thrive in areas with: 

• Clean air (yes, it’s a sign of good air quality!) 

• High humidity or moisture 

• Trees with slow growth or thinning canopies 

  
  

They’re most noticeable on older or stressed trees, which is why some homeowners worry they’re a sign of disease. But rest assured, lichens are not parasites. However, their presence may highlight underlying issues that are worth addressing. 

Lichen growing on the bark of a tree, showcasing the symbiotic relationship between fungi and algae in a natural environment.

Should You Be Concerned? 

Lichens themselves aren’t a threat, but they can signal that your tree might not be in peak health. That’s where we come in. 

At Rich Green Lawns, our tree and shrub care services can assess the overall health of your landscape and recommend proactive solutions like: 

• Deep root fertilization 

• Insect and disease control 

• Soil amendments for better nutrition 

• Improving airflow and sunlight through proper pruning (when needed) 

  
  

How to Manage Lichens 

If lichens are growing on trees in your yard, here are a few tips: 

• Do not try to scrape them off — this can damage the bark. 

• Improve overall tree health with proper feeding and watering. 

• Let professionals assess the condition of your trees to rule out other stress factors. 

  
  

Trust the Experts at Rich Green Lawns 

We believe healthy trees and shrubs are just as important as a lush, green lawn. Whether it’s lichens or something more serious, our team is ready to provide expert guidance and effective care. 

📞 Call or message us today to schedule a free consultation and give your landscape the attention it deserves!