Why does the sight of mushrooms popping up in a lawn or flower bed cause such annoyance?
Mushrooms are a fungus, not a true plant. The fact that all mushrooms are fungus is probably the root of the issue. The term “fungus” has about as much charm as a hangnail. Humans don’t like fungus; we treat fungus, we apply ointment for fungus, we see doctors and specialists for fungus. We live our lives with a goal of ‘fungus avoidance.’
Mushrooms thrive in warm, damp, organic areas of gardens, forests and woodlands. The actual fungus is a threadlike organism in the earth and usually unseen. The mushroom is the reproductive structure or "flower" or “fruit” of a certain family of fungus. The mushroom is usually comprised of a flattened cap attached to a stalk. Underneath the cap are rows of gills which house reproductive cells, called spores. These spores are released by wind to produce more fungus.
Mushrooms live on organic matter. The more decaying organic matter your soil contains, the healthier it is, the more fungus it will support and therefore the more mushrooms it will grow. These fungi and the mushroom they produce live on dead or dying plant roots, old decomposing mulch, rotting wood, construction debris buried in the soil, decomposing thatch and decaying animal waste. Large amounts of fungus are alive and well in healthy soils and are a part of the basic soil food web that gardens and plants depend upon.
There are many different types of soil fungus. No matter what type they are, the majority doesn’t cause any serious damage to plants, but in most cases, gardeners view them as unsightly and unwanted.
Of the three classes of mushrooms, most if not all are crucial to healthy garden ecology. Most soil fungi are saprophytic, meaning they help decompose dead leaves and other organic debris, turning it into humus, a vital component of healthy soil.
Some soil fungi are mycorrhizal, meaning they form a mutualistic relationship with various garden and forest plants. The plants’ roots and the mycorrhizal fungi form a relationship in which both receive a benefit. This web of interaction in the soil is crucial to keeping water and minerals available to each participant, the plant and the fungus. In fact, the best organic fertilizers, like Dr. Earth, and some soil amendments actually contain thousands of spores of these beneficial types of fungi as a useful ingredient.
Although the least likely of the group, a third type of mushroom is parasitic. Most of these are simply opportunistic fungi, moving in once a host plant has been weakened for some other reason. They will occasionally live upon a host that is not quite dead yet, but soon to be. Among others, these fungi include a group commonly known as bracket or shelf fungi, also called polypores, and produce a mushroom like growth on dead and dying tree trunks. When you see these growths on the bases of sick trees, it’s not the mushroom that killed the tree.
Since mushrooms thrive in moist, slightly warm conditions, now is a time you may notice a great many of them. Recent heavy rains encouraged these fungi to “fruit” – the mushroom.
If you’re still not convinced and just can’t tolerate the sight of a few mushrooms ruining the otherwise perfect organization of your garden you can simply knock them over or pick them up and toss them into the compost pile. Applying a fungicide is of little value and very temporary at best, since the fungus is below the soil surface and out of reach of the chemical.
With more rain inevitable, more mushrooms will appear in your gardens. With a little understanding and knowledge, perhaps you will have fewer fungal frustrations.
Questions from Readers January 22.
My young boxwood hedge is turned a dull brown color, but I can’t find any insects on it. Should I be watering it more? What should I fertilize it with? I’m afraid it is dying.
Allanis, Costa Mesa
Your boxwood is simply reacting to the cold weather. Unfortunately, many boxwoods sold in Southern California are still older hybrids that react poorly to cold winter temperatures. They react by discoloring, usually to shades of dull brown or irregular rusty orange tones. Once the weather warms up, they will green up again and begin growing. In the future, always look for hybrids like ‘Boxwood Beauty’ or ‘Winter Gem’ which keep their green color all winter.
Ron Vanderhoff is the Nursery Manager at Roger’s Gardens, Corona del Mar.