Lichens Can Draw Attention to Plants’declining Health

— Written By and last updated by Diane Lynch

Part fungi, part algae, they’re not the cause of damage-they simply attach themselves to plants already in distress.

Q: I have a gray something growing on the bark of my tree. What is it and will it harm my tree?

A: It sounds like you maybe describing lichens. Lichens are a common site on branches of trees and shrubs. Seeing lichens can be an unusual site in that it looks like a strange thing is taking over the plant. It is often thought that lichens are a fungus or disease that is damaging the plant but that really is not the case.

Lichens are a unique organism in that it is a fungus and algae combined to live together. Although lichens really do not look like a fungus or algae both work together so that lichens can survive. The alga uses photosynthesis to produce food while the fungus supplies water and structure. This combination allows for lichen to be very adaptable to extreme environmental conditions which is probably why lichens can be found on every continent including Antarctica.

Lichens can be found on a wide range of surfaces including limbs, branches, stumps, rocks, fence post, and even on the soil. Lichens firmly attached themselves to these hard surfaces. This gives the impression that lichens are sucking the life out of a plant when really they are living on their own and producing their own food but use the branches as a place to simply attach itself to.

Lichens prefer to locate themselves on surfaces exposed to sunlight. When lichens are seen on branches of a tree or shrub the branch usually has little foliage giving the appearance that the lichens are causing the plant to decline in health. Really lichens do not cause plant damage but instead are a sign that the plant itself is declining in health due to some other cause like environmental stress, poor management, or being planted in the wrong location. When the plant is stressed or unhealthy, typically a decrease in foliage occurs allowing branches to be more exposed to sunlight, thus providing a great location for lichens to call home.

Keeping plants in good health is the best way to reduce the amount of lichens on a plant. A heavy infestation of lichens is a sign that the plant is currently in poor health. If the lichen infestation is bad enough it maybe a sign that the plant needs to be replaced. Keeping a plant healthy by proper watering, fertilizing, location, and care will encourage a thick leaf canopy and reduce the amount of lichens. For limbs with a lot of lichens, light pruning can remove some of the lichens and stimulate new growth which will help shade out the rest.

While lichens are a sign that the plant is in poor or declining health, do not be alarmed if you see a few lichens here and there. A few here and there on a plant is ok.

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Upcoming Wayne County Extension Gardening Programs:
• Wayne County Gardening – Spring Workshop Series. The Wayne County Extension Office will be offering workshops featuring popular gardening topics. Workshops consist of a presentation, question and answer session, and handouts to take home. All workshops are free and open to the public. Registration is required for all workshops by calling the Wayne Co. Extension Office at 919-731-1520.

  • Home Vegetable Gardening Workshop – Friday, March 20th, 9 a.m. to noon at Wayne County Extension Office, 208 W. Chestnut Street, Goldsboro. Nothing is more rewarding than to raise and harvest fresh vegetables from your own backyard garden. This workshop will cover how to plant and start a vegetable garden along with how to care for it through out the season. No matter the size of your vegetable garden, this workshop is for you!

Save the date for the annual Extension Master Gardener Volunteer Spring Plant Sale! This year’s plant sale will be Saturday, April 18th at the Wayne Center of the Wayne County Cooperative Extension Office (208 W. Chestnut Street, Goldsboro). Doors will open at 9 a.m. and stay open until noon.

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Jessica Strickland
Extension Agent
Horticulture
North Carolina Cooperative Extension
Wayne County Center
P. O. Box 68
Goldsboro, NC 27533
E-Mail: jessica.strickland@waynegov.com
Phone: 919-731-1520
Fax: 919-731-1511
https://www.ces.ncsu.edu/wayne