Yuck, what’s that brown stuff in the mulch next to the shrub? Is it dog vomit? Also, I notice light green spots on the branches and trunk of my tree. What’s going on?
When the environment remains moist due to frequent rain showers, the ideal conditions are formed for the development of crisp green material on tree bark and light brown spots in the mulch.
It can look like an invasion or terrible diseases. However, the crusty material on the branches and trunks of trees, called lichens, is easier to see in wet weather. Tan-colored spots, which can form on plants and mulch, are caused by slime mold, not a dog.
Fortunately, both are harmless.
Most commonly, lichens appear as a perennial green or gray coating on the trunks and branches of trees and shrubs. In reality, they are two organisms in one, consisting of a fungal body housing green or blue-green algae, which cohabit in perfect harmony.
In the symbiotic relationship, the algae, through photosynthesis, provide carbohydrate food to the fungus and in turn receive protection, trapped water and mineral elements from the fungus.
In this relationship, algae and fungi are only distinguishable under the microscope, and the lichen persists longer than the algae or fungus would separately.
Lichen color can include green, blue-green, yellow-green, brown, gray or even red forms. They take various forms on trees and shrubs. Some are closely appressed to the surface of the bark and are described as crustaceans.
Foliose lichens have leaf-like lobes extending from the surface of the bark. Others have hair-like or strap-like shapes and are called fruticose lichens.
Lichens do not parasitize trees but use the bark as a place to grow. In fact, lichens can be seen growing on rocks, on weathered wood, or on dead branches that have fallen from the tree.
Some may consider lichens unsightly, but they are generally not harmful, except that when they are extensive they can interfere with the gas exchange of the parts they cover. Due to their extreme sensitivity to sulfur dioxide air pollution, lichens rarely appear on trees in industrial cities.
Lichens rarely grow on fast-growing trees because new bark is constantly forming before lichens have a chance to grow over much of the surface.
Therefore, lichens on some species may indicate poor tree growth. In some plantings, the more vigorous trees have fewer lichens than those of the same age nearby in a state of decline.
However, few studies have been conducted to verify any correlation between lichen growth and tree vigor. Lichens proliferate when more light is provided, which could explain why they are more commonly seen on dead, leafless branches. In addition, increases in lichens are sometimes associated with a humid climate.
Slime molds are amoeba-like organisms that feed on bacteria and yeasts in the soil. Looks like a dog had a stomach ache. Molds appear quickly as white, cream, gray or purple 4 to 6 inch patches with a crusty surface. Some grow a foot or more in size.
In cloudy and humid weather, these molds come out of the ground and creep on everything that is available. They use plants and mulch as support structures from which spores are spread by wind, water, lawn mowers, other equipment, or the movement of people or animals.
Lawn, weeds, strawberries, bedding plants, and ground covers, as well as mulches, sidewalks, and driveways can become covered in masses of dusty gray, yellowish, or black spores.
Although slime molds often cause considerable concern among homeowners, these fungi do not feed on plant tissue. Slime molds simply use low vegetation and other objects as support during their reproductive phase.
When fungal growth is heavy, the shaded parts of the plant turn yellow. Checks are usually not necessary because slime mold causes little damage and usually disappears with the onset of dry weather.
When slime mold infestations are heavy, the spore masses can be broken up with a rake or broom. Watering with a strong stream of water is also effective but should only be done after the onset of dry weather, when the threat of further development has passed.
Washing out slime mold in prolonged humid weather will only help spread the organism to previously unaffected areas. Slime molds that form thick layers or masses can be removed by hand or by removing the affected plant part.
Remember that lichens and slime molds are not harmful. For more information, contact the Daviess County Cooperative Extension Service at 270-685-8480 or email email@example.com.
When considering which shrub or tree to buy for your landscape, make sure it will grow in plant hardiness zone 6. The United States Department of Agriculture plant hardiness zone map is based on the average minimum winter temperature, divided into zones of 10 degrees. Zone 6 has an average annual minimum temperature of -10 to 0 degrees. Plants that grow in zones 7, with an average minimum temperature of 0-10 degrees, would not overwinter in our zone 6. They will be pretty during the summer but will die during the winter unless the plant grows in a protected place. place where it is warmer. Plants from zones 4 and 5 will grow here, but some of them may suffer from the heat, but they will survive our cold temperatures.