Bark chippings are commonly used as mulch around trees and shrubs. They protect plants from mechanical damage, reduce weed growth and help the soil retain water. Fungus may occasionally grow on bark chippings.
Dog vomit slime mould ranges in size from 1 to 2 inches to more than a foot long. It is usually orange or yellow with a slimy, liquid texture, but later dries out and turns powdery white. Mushrooms and toadstools vary in shape and size depending on the species. The artillery fungus produces small creamy-white or brownish-orange cups filled with black spores.
Slime moulds and mushrooms are not harmful to trees and shrubs and do not pose a danger to humans unless they are ingested. The artillery fungus can be a nuisance, however, because it releases sticky black spores that attach to surrounding objects. The spores leave unsightly stains when they are removed.
Slime mould is a temporary nuisance that usually confines itself to small areas. You can either leave it where it is to decompose or bag it up and discard it. Mushrooms and toadstools should be removed to protect small children who might be tempted to eat them. You can control artillery fungus by replacing bark mulch with a nonwoody substance such as plastic or stone.