What Is Growing in My Yard?

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Ever find something in your yard and wonder, “What is that?” If so, you are not alone. Throughout the year people bring bugs, plants, and mysterious growths found in their yard to their local Cooperative Extension office for identification. Among the items most frequently brought in that fall into the category of “mysterious growths” are algae, lichen, and stink horns. All three of these are common throughout our region, which means there is a good chance you may find them in your yard too.


Star jelly is a type of algae sometimes found where the soil is very compacted.

Star jelly is a type of algae sometimes found where the soil is very compacted.

What’s green, gooey and mainly shows up after rainfall? Nostoc commune, a type of blue green algae sometimes referred to as star jelly or witch’s butter. Under warm, rainy conditions this land loving algae forms dark green, jellylike mats in lawns, driveways, and parking areas. When the sun comes out it quickly begins to dry up, progressing from a gummy blob to a dry crisp mat within a few hours. Drying out does not kill this algae; It simply goes dormant, waiting for the next rainfall to rehydrate and plump up again.

Abundant rainfall made 2012 a great year for this type of algae to multiply in our area. Other than being unpleasant to walk on, star jelly is not harmful and is actually eaten in some parts of the world. It is most often found where the soil is very hard and compacted, and can grow in shade or full sun. In lawns, it grows where the grass is already weak and thin, leading many to incorrectly think it is the cause of their lawn’s decline. In most cases the real issue is either extreme soil compaction or over irrigation, or both.

When applied regularly, some fungicides will help control star jelly but will not get rid of it permanently. On hard surfaces like driveways and parking areas, it can be raked up when wet and added to the compost pile. In lawns, the best way to deal with star jelly is to modify your irrigation schedule and aerate the soil in early summer.



Lichen is not a cause of plant disease.

Have you ever noticed a grayish-green crusty or mossy looking growth on the stems of trees and shrubs in your yard? If so, then you have encountered a lichen (pronounced “liken”), an interesting life form composed of an algae and a fungus living together. Lichens will grow on anything that sits still long enough, including slow growing plants, tree trunks, rocks, fence posts, fallen logs, tombstones, and even the ground.

Lichens do not harm the plants they grow upon, but often plants that are struggling will be covered in them. When lichens are found growing prolifically on a plant that also has lots of dead twigs and branches it is usually a sign that something more serious is wrong such as root rot, drought damage, or soil compaction. Diagnosing and correcting the underlying problem is the only way to return these plants to health.

Stink Horns

Stink horns are a type of mysterious growth that is usually smelled before they are seen. True to their name, these mushrooms emit an order of rotting flesh. They are usually found growing in landscape beds with hardwood mulch. One of the most common in our area is the octopus stinkhorn, which looks like an orange octopus or squid popping up out of the mulch.

stink horn

Stink horns truly live up to their name!

Other types of stinkhorns, of the genus Phallus, take on a more x-rated appearance, resembling a certain part of the male anatomy. All stinkhorns grow from egg-like sacks that can be found in the mulch they inhabit. The stinkhorn and the egg-like sack are the reproductive parts of a larger body mass, which is made up of white, thin threads known as hyphae. Like all mushrooms, removing just the visible growth does not get rid of the fungus because the majority of its body is left behind.

Despite the way the smell, stinkhorns are harmless. Individual stinkhorns only persist for a few days and are most common in the spring and fall. Switching from hardwood mulch to pine bark mulch or pine straw can help reduce the occurrence of stink horns.

Learn More

Visit your local Cooperative Extension office to learn more about gardening and landscape care. Go to https://www.ces.ncsu.edu/local-county-center/ to find your county Extension center.