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Honeys - Armillaria mellea (by Mark Benson)

(Reposted from posting on google groups with photos courtesy of Hugh Smith)

How about all this rain! 

Those were a beautiful display of Honey Mushrooms, Hugh!  Tight and turgid and just the right time to harvest.

Seeing them prompted me to write a few lines about Honeys not from any formal knowledge...but from my work experience and from 'experts' with whom I consulted for my clients in my work with trees.  I hope it is helpful to some of you.  I am not a scientist...just an observer.

What I have learned is that some sp. of "honey" mushrooms are more aggressive than others (i.e. our Armillaria mellea complex are very aggressive).  Under certain unnatural conditions, they can/do attack and kill live trees ...and don't just fruit from dead stumps.  They attack many sp. such as oaks, our native maple, other native flora like native grape vine and many ornamental/orchard trees and shrubs, vines (blackberry).  Another potential plant foe, Phytophthora root rot, can be colonized by Armillaria sp. ("Honeys") and spread through that organism as well.

This will not be news to many of you...but hopefully of interest to some newer members of the club, or others who are gardeners or stewards of one or more beautiful oak trees.  Aside from being a potential host for delicious Chanterelles and other benign edibles...Oak trees, especially in urban settings under certain conditions, can attract parasitic "Honey" mushrooms which you saw in Hughs spectacular photos. 

Tree culture is a subject near and dear to my heart.  I love oaks so much that I named my first horticultural business, 'Acorn Tree Service'...which morphed into 'Green Mansions Tree and Horticultural Specialty Services'.  As an arborist/landscaper in So. Cal. for many years, I had to remove many dead or declining oaks after their battle with Honey Mushrooms ("Oak Root Fungus", Armillaria m. complex).  I did not know that these shrooms were considered edible back in those days.  In fact, not until I joined the FFSC a decade or so ago had I ever eaten a wild mushroom.  (I made my wife eat a Chantie she harvested then I waited 48 hours!)  Of course, she had harvested edibles in Kentucky for years before moving out here.  I was just a city boy, an urbanbushman...what did I know?

In the urban setting, generally speaking, Honey mushroom attacks on oaks and other ornamental trees/flora or orchard trees can be avoided...or halted in the early stages.  Oaks in an undisturbed habitat are generally protected naturally.  Obviously, though, trees fall or are damage or are cut down in the woodlands as well.

A specialty preventative or 'habitat remediation' service I offered was to restore the area under oaks from drip line to trunk as a 'fungus-free zone'.  What would lead to an oak's demise all too often (and had to be removed or dealt with sooner than later) were an accumulation of man-made objects (used tires, boxes of tiles, etc.) or firewood stacked up against the trunk or misguided water-thirsty plantings needing frequent Summer water, water basins fashioned from brick, stone or wood around the tree's base, etc.  Surplus soil or mulch built up above natural grade would also act as a wick or conduit for untoward mycelium to infiltrate the trees natural defenses between root crown and trunk.  It all had to be removed or redistributed.  Irrigation systems simply had to be reconfigured, redirected or yanked out.  Older, established Oaks hate Summer water.  Honeys love it.

If a client wanted more than my preferred minimalistic design (letting oak leaves fall, naturally to cover the bare earth) I would 'plant' a few large, loosely arranged mountain stones, spread out away from tree trunks and/or I would plant and establish sparse native flora then call it a day.  My main "design" and intent in this type of job was of a restorative nature and to prevent invading parasitic mycelium tendrils. 

We had a registered heritage oak tree (estimated 400 plus years of age) in my home town of La Canada (pron. "lah canyada") that finally went into decline.  I was one of many people called to consult with the property owners.  The estate had changed hands a decade or so before and the new owners (from out of state) had immediately re-landscaped the entire property and over-trimmed the old tree "to favor the new plantings with air and light", not understanding the aforementioned cultural dynamics and consequences.  It had taken about 10-12 years but the fungus won.  Still barely alive, opportunistic beetle grubs finished the job and an iconic oak was lost to the community.   

Many folks who were my customers will have a regular supply of 'honeys' for a real long time.  Armillaria can survive as rhizomorphs and vegetative mycelium in the soil for years hanging around old stumps and roots, dead or alive.  Tough to control.  A real bad actor in the wrong places.  On the positive side though...good eating for some folks.  Just avoid inadvertently introducing this particular fungal bonanza to your own vegetable garden...or your neighbor's by introducing white mycelium threads from your boots.

For those who want to read more about different flora's susceptibility or resistance to "oak root fungus" and other related info, there is much to study on line.  Here is one link: 

http://ipm.illinois.edu/landturf/diseases/armillaria/

(Including the Armillaria community)

m.

• attached gills
• pesistant ring on fiberous stem
• growing en-mass an the base of a sickly Quercus.speckled roughened cap
• sometimes orangey gills at age
• a tough outer stipe that peels away like string cheese. 
• white spore drop color can often be seen in the field, by observing the tops of caps under other mature caps