Q. I have this plant (weed) growing in my front yard starting last year and it appears to be getting worse. (See attached) It becomes green and slimy when it gets wet. I would like to know how I could get rid of this so that grass starts growing. —A.G., Dallas, TX
A. These blobs of green gel are colonies of nostoc that is bacteria get their energy through photosynthesis. When on the ground, nostoc is ordinarily not seen, but after a rain it swells up into the green jelly-like mass. Once thought to have fallen from the sky it has the common names – star jelly and troll’s butter. It dries to a black crust but comes back to its green life when there is sufficient moisture.
To discourage its growth, improve drainage and eliminate synthetic fertilizer use. Vinegar and fatty acid herbicides can be used to kill it in lawns if it bothers you but there is really nothing harmful about it. N. muscorum is known to have major impacts on soil structure, chemistry and biology. In some countries, such as Peru, nostoc is used as a seasonal dietary item, being eaten alone or in picante — a local stew — and is said to be highly nutritious.
