View Full Version : Mulch causing fungus?

12-29-2004, 09:23 PM
I was talking to the general manager at a car dealership, trying to put in a bid for a maintaince contract. He said they would have to do something about the mulch because it was causing fungus on the cars. Has anyone heard of this? Could any one type of mulch be better in this situation (less dusty, less rain splatter...)? Or is he just imaging things... Thanks, Joe

12-29-2004, 09:49 PM
I've never heard of it on the cars. sometimes the mulch grows *****' as my mom says. I'm not sure there is anything you can do about it though.

12-29-2004, 09:53 PM
Thanks for the input. Joe

D Felix
12-30-2004, 09:57 AM
I suppose that it's possible that the mulch could be supporting an artillery-like fungus, that when it releases its spores the spores end up stuck to the car....

The cars themselves shouldn't be capable of supporting mold/fungal growth, at least not on the outside. Unless of course they don't wash the cars at all.:D


12-30-2004, 05:58 PM
Thanks, Dan. I hadn't thought of that. Do you think that pine straw would be better than pine bark mulch in that situation? Maybe it would have better air flow and less fungul growth...

D Felix
12-31-2004, 09:47 AM
I don't know about the pine straw.... I've never used it.:)


01-13-2005, 07:09 PM
Pine straw stinks IMHO. Especially in a commercial application. It' fades quickly and is impossible to keep clean of debris. Try using brown dyed mulch (yeah, I know) I haven't seen any fungus growing an any I've installled. It will also retain it's color for a longer period of time. Just realize it requires a little extra to obtain the same coverage of regular mulch.

01-23-2005, 10:01 AM
i agree with the not caring for pine straw, BUT it is extremely popular here.
we will apply 3-5thousand bales this year.

we try and switch people over to shredded hardwood, or cypress. but is is almost twice as much/area.

pine bark nuggets, shredded, or in full pieces is a terrible mulch, as far as the functions of mulch goes.
ever consider treating with a fungicide like rubigan, etc?

01-29-2005, 08:16 PM
I agree w Felix. Mulch probably provides an excellent breeding ground for fungus and although fungus spores are airborne and really everywhere, the car would not be a host. Thats an interesting observation from a car salesman though, it could be a pollen of sorts.

I like pinestraw for certain applications, it's easy and you can quickly spuce up a property. To think that it's "airy" and is less likely to provide an environment for fungus, I would say is misguided. Once the pinestraw is down and the elements get to it, it becomes like a moist blanket, under which you have an excellent place for all sorts of good stuff.

Be careful using wood chips, shreds (dyed or other) and the like if your going to have flowers and ornamentals installed. When many of these wood types breakdown, the process actually takes nutrients (primarily nitrogen) from the ground and your more fragile plants can suffer, depending on the size of the area, this could be represent a considerable loss. As yardpro stated, hardwood or cypress is good. I think you could consider bark, depending on the terrain. You can also nitrolize your other wood mulches w some fert.

01-29-2005, 09:25 PM
how about putting done some rock or stone for mulch there so many kinds out there and it adds color

02-11-2005, 07:03 PM
Hardwood mulch can be a host of various forms of fungi. You have to understand that hardwood mulch is breaking down constantly, thus micro organisms are present as well as insects. That is just the process of mother nature. There is a problem in my area of what we refer to "Dog-Vomit" fungus. It appears as just that, as if you or your dog upchucked on the mulch. Once this dries, then the spores are air born. What we do is just take a shovel and flip it over to hide the not so asthetically appealing site of the fungus. There is another one that I can't think of the exact name, but I will refer to it as the "Shotgun" fungus. This is probably what the car salesman is most likely refering to. This creates spores that can actually rotate to light. So in your case, a nice shiney car that is reflecting the sunlight is a definate attractant. It then shoots out spores that can go as far as 14 feet. It is really noticable on siding and anything with a light color. I even had it at my previous residence. These spores are not easy to get off. The local extension agent for my area just recently spoke on this at a seminar, and said that even pressure washing is sometimes not effective in removing the spores.
I like the idea of pinestraw, though in your area it might not be readily available. I would suggest advising him on making a capital expense improvement and look into installing stone or switching to bark mulch. Bark mulch does not break down that fast and is very light. Check with a local University and their plant and soil science dept. or contact your local extension service for some other ideas for your region.

02-13-2005, 09:24 AM
TScapes Thanks for the reply...Great info. I'm still talking to the dealership about a service contract. this will help out a lot. Joe

03-16-2005, 11:42 AM
May be too late but check out the attached link. Moving away from wood products (to bark) may be an option. This fungus is rampant up here and is next to impossible to clean off the spores! I can see why the car dealer would be frustrated.

One other note, the fungus has a life span of over 10 years and can reappear when the conditions are right.


jd boy
03-16-2005, 12:10 PM
shot gun fungus is a big problem in nw ohio. people with vinal & aluminum siding usually have to power wash their homes when they've had it. It is amazing how far/ high the fungus will go. Often we will see it on the soffit, which is what 9 or 10 '.

That is why mulch should go on 2" thick not 6!

03-16-2005, 03:51 PM
Thanks for that link, Karen! I am actually trying to get my customers to switch from hardwood mulch to some other form, preferable pinestraw, since it is cheaper for me to put out. Good info!

old dog
03-16-2005, 10:20 PM
how about putting done some rock or stone for mulch there so many kinds out there and it adds color
Sounds like the only way to got to me!Brick chips-maybe white marble
chips but tthey had better get ready to shell out the first time.I would take the old mulch out and lay landscape fabric first1

03-16-2005, 11:02 PM
It's known as artillery fungus or also nicknamed shotgun fungus. And no...pressure washing will not take it off of a car, a house or anything else for that matter, unless you do it within a week or so after it has landed onto the item. After that it is impossible. It will shoot up to two stories high. Penn State did a study on it and they actually gave it a horsepower rating of when it pops. It isn't very big, but when it's left go and year after year or in bad cases, it is very visible when it becomes concentrated in one area. Each spore is like a half sharpened #2 pencil point. The harder the mulch (tree) the less chance it has to grow. But the best thing to do is used a decorative stone. Go to google and do a search on penn state artillery fungus. In that article, it talks about a local landscaper who installed the mulch and what he did. I personally have it on my own house, but will never put down any more mulch because it is unsightly. Let's see if I can copy and paste.
July 3, 1997

UNIVERSITY PARK, Pa. -- It barely takes up the space on a quarter of a match head, but the artillery fungus shot enough sticky, black spore masses at homes and automobiles last year to cause more than $1 million in homeowner damage claims in Pennsylvania alone.

Researchers in Penn State's College of Agricultural Sciences are involved in a five-year study of the fungus, commonly found in wood-based landscape mulch. Mulch beds can be infected by the fungus in various ways--it can grow on trees that become mulch, or a leaf that contains spore masses can blow into a mulch bed.

Artillery fungus, also known as shotgun fungus, is a wood-rotting variety that prefers sunny, damp areas. It is so small that even experts have trouble finding it in mulch, but it gives the wood a bleached appearance, says Larry Kuhns, professor of horticulture. This particular type of "mushroom" is a small cream or orange-brown cup containing a black, round mass of spores. Spore masses are produced when temperatures are between 50 and 68 degrees Fahrenheit, typical of the spring and fall seasons.

The fruiting body points itself toward strong light sources such as sun-reflecting glass and light colored buildings and cars. As the body matures, it opens like a flower, revealing the mass of spores in the middle.

Five hours after opening, the inner cup inverts and violently ejects the spore mass, with a 1/10,000 horsepower force, as far as 20 feet. The spore masses, which are sometimes mistaken for insect frass, adhere to any surfaces they contact. They cannot be removed without damaging or staining the surface and are viable for at least 10 years, says Kuhns, who is conducting the research with Don Davis, professor of plant pathology, and Beth Brantley, graduate student in plant pathology.

The project's goal is to examine the conditions under which Pennsylvania's native wood can successfully be used as fungus-free mulch, taking into account variables such as wood-to-bark ratios, the tree species (hard vs. soft wood) used in the mulch, how long it should be composted and whether mulch additives would prevent fungus growth.

"I don't have a lot of hope for fungicides because it's hard to determine when the mulch becomes infected, making the timing of the application critical and difficult," Kuhns says. "Preliminary results indicate that the fungus doesn't grow in rot-resistant woods like redwood, cedar and cypress," he adds, stressing that all results are very preliminary and experiments have not yet been repeated to validate the findings.

Brantley says the fungus seems to grow on either wood chips or "double shredded" bark mulch--the dark, organic-looking, thin-stranded mulch.

"We'll also be looking at ways to remove the fungus without causing staining or damage to adhered surfaces," Kuhns says, adding that except for cosmetic damage to man-made structures, the fungus is not a hazard in any way.

But this cosmetic damage is causing a lot of concern for the state's mulch-producing industries. Stringent new landfill regulations in recent years have forced increased recycling of waste products generated by wood-product manufacturers, lumber mills and land clearing for development. Consequently, landscape mulch production has become an important outlet for these wastes and a significant source of income for these industries.

As the demand for landscape mulch has increased for ornamental reasons, the fungus has become a larger problem. Mulch-producing industries fear widespread changeover to synthetic plastic or black pellet mulches.

Some businesses already have felt the effects of the fungus on their pocketbooks. Rick Shawley, president of the Bellefonte landscape company Nature's Cover, says he has had complaints on all seven mulch varieties he sells.

"To keep customers happy last year, I gave people 50 percent off of some products and paid a couple thousand dollars to appease everyone," Shawley says. "This year I'm selling quite a bit more decorative gravel."

The fungus is found nearly everywhere in the United States, except for dry areas like Arizona. It is a major problem in New Jersey, Ohio and Pennsylvania because of the type of wood available, Brantley says, and it is often confused with another fungus common to this region--the bird's nest fungus. There is little genetic information available on the artillery fungus, scientifically known as Sphaerobolus stellatus, but the bird's nest fungus probably is a close relative. The study, which is supported by the Pennsylvania Department of Agriculture, will include DNA analysis of the fungi, she says.


EDITORS: For more information, contact Larry Kuhns at (814) 863-2197 or Don Davis at (814) 865-1689, or point your Web browser at http://www.personal.psu.edu/faculty/d/d/ddd2/artillery_fungus.html.

03-17-2005, 02:37 PM
how about putting done some rock or stone for mulch there so many kinds out there and it adds color
That was my first thought too.