Fungus Among Us

by Ken Muellers

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When you are enjoying a beautiful day outside relaxing in the garden, fungus all around you is probably not what you are thinking about. Yet fungi (the plural of fungus) are all around you, and they are key elements of your landscape.

Many fungi are integral to a healthy ecosystem. If not for fungi our forests would be piles of dead trees with nowhere to go. Fungi (and time) are the essential destroyer of all living things. They breakdown organic material for recycling in the environment. Fortunately, most fungi only decompose dead material, leaving healthy plants to grow.

The most obvious sign of fungi in the landscape are mushrooms. Mushrooms are the reproductive part of the life cycle of fungi that distribute spores that spread the fungus. Seeing mushrooms in your garden are often, but not always, an indication of something going awry. Mushrooms commonly show up in the lawn when the lawn is overwatered. This is because fungi typically thrive in moist conditions, making mushrooms a good indicator of too much water. And while we are on the subject of mushrooms, keep in mind that while some mushrooms are edible ­– like a nice portobello – others are toxic. Unless you are an expert, it is very hard to tell the difference so don’t pick your own for snacking.

Aside from being a sign of too much moisture, another landscape problem fungus can indicate is rot in trees and root systems. As mentioned, most fungi attack dead wood, so if you have a tree conk (that thing that looks like a dinner plate stuck in the tree) growing on the side of a tree or some funky looking growth at the base of the trunk, this is usually a sign of internal decay. If you notice these you may want to have a professional arborist take a look at the tree to see if it poses a hazard.

Some fungi manifest themselves as diseases that can damage and even kill plants. Leaf rusts, powdery mildew, black spot and anthracnose are just a few problems caused by fungi. Since moisture is a key component in the spread of fungi, it is important to avoid overwatering and unnecessarily wetting the leaves of plants to avoid fungal problems.

One of the most important beneficial fungal relationships in the landscape is one you don’t see that takes place below ground. The roots of most plants have a symbiotic relationship with a special type of fungus called mycorrhizal fungi which are critical to a healthy landscape. This alliance, which has been going on for millions of years, is just starting to be fully appreciated by gardeners. These fungi grow on and in the roots of 90% of all plants. The fungus receives nutrition from the plant and in exchange, the plant gets greatly increased root capacity to absorb water and minerals. Horticulturalists have realized the importance of these fungi and often will introduce the mycorrhizae into the soil with inoculates to help plants get going. Without these mycorrhizae, many plants simply cannot survive. So be thankful for these fungus among us.