Mulch Volcanoes Are Erupting Everywhere!

A colleague of mine wrote this.  I just had to share.  This is a huge problem.  Please help spread the word that volcano mulching is incorrect.  Trees should not be mulched this way.  You can distribute my mulching publication to anyone has trees mulched this way.  Thanks.

By Sandy Feather

Penn state Extension Educator, Green Industry

July 19, 2018

Mulching like this is not good for the tree!

Properly applied organic mulches are very beneficial for trees. Preferably two-to-three inches deep, not physically touching the trunk, and extending out to the drip line. They help conserve soil moisture, which reduces the need for frequent irrigation. Organic mulches also help moderate soil temperature, protecting fragile feeder roots from temperature extremes. They help keep weeds down, at least until mowing blows weed seeds into the mulch where they happily germinate. Organic mulches also add organic matter to the soil as they break down, improving soil structure, porosity, and nutrient-holding capacity. And all types of mulch protect vulnerable trunks from weed whacker and mower damage.

However, trouble starts when the mulch is applied more heavily and in constant contact with a larger section of the tree’s trunk. When wet, the mulch holds too much moisture against the bark, which can cause it to start to break down. And as the mulch starts to compost, it heats up, which can further damage the bark and the underlying vascular tissues, compromising the tree’s ability to transport water and nutrients.

Too much mulch also blocks the roots from getting sufficient oxygen, and if the underlying soil remains too wet for too long a time, the roots begin to rot. It can also cause the tree to develop adventitious roots – those growing from trunk tissue, rather than true root tissue. As they grow in diameter, they can develop into girdling roots, which further restricts the tree’s ability to transport water.

Finally, when we get into hot, dry summer weather and the mulch completely dries out, it becomes hydrophobic and actually repels water. Trees mulched in such a way cannot benefit from rain as properly mulched trees do.

Given the problems associated with volcano mulching, why is it so common? One reason may be that clients dislike the tired look of existing mulch after a long winter. So landscape companies refresh the mulch without regard to the depth of the existing mulch. A better practice is to rake out the existing mulch and place a very thin skim layer of fresh mulch over it.

Another reason may be that time is money. It is faster to dump a wheelbarrow full of mulch around a tree than to place it more carefully. You can sometimes see the results when mulch is deeper on one side of the tree than the other. While acknowledging that the tasks done by landscape crews have to be done efficiently to keep a company profitable, surely the small amount of extra time required to make sure that mulch is properly applied should not break the bank.

Another issue is the monkey-see, monkey-do effect. When homeowners see landscape professionals engage in volcano mulching, they conclude that volcano mulching is the appropriate way to mulch their property. Unfortunately, they are incorrect.

Spotted Lanternfly Update

Photo by Greg Hoover

This is the time of year when adult emergence of Spotted Lanternfly will be visible within the 13 county quarantine area. A high level of vigilance is required by everyone that works and/or travels into and out of the quarantine zone.

As many of you are aware, the spotted lanternfly (SLF) is a new invasive insect that was first discovered in the US in Berks County in 2014. It has since spread throughout 13 counties in southeastern PA, which the PA Department of Agriculture (PDA) has designated as a SLF quarantine zone.

Because this is the first population of the SLF outside Asia, it’s difficult to assess the magnitude of the threat that SLF presents, but it is potentially the worst introduced insect pest since the gypsy moth nearly 150 years ago. From what we know, the SLF is a significant threat to PA agriculture, including grapes and tree-fruit (where heavy damage has already been recorded), landscape nurseries, and the hardwood industries, which collectively are worth nearly $18 billion to the state's economy. In addition, this insect threatens outdoor recreation, backyard enjoyment, and biodiversity.

It is everyone’s responsibility to use “best practices” when entering and/or leaving the quarantine zone. This is no different than using biosecurity practices for human or animal diseases. Failure to follow best practices could result in the pest being moved into new habitat leading to additional economic impacts to the state of Pennsylvania.  We all must take the quarantine seriously.

Please review the below resources provided by the Pennsylvania Department of Agriculture and Penn State Extension:

• Look Before You Leave
• Spotted Lanternfly Pest Alert
• Spotted Lanternfly Checklist

Before moving between quarantined sites or leaving the quarantine zone:

• Check yourself before getting into the vehicle to make sure no Spotted Lanternfly nymphs or adults have attached themselves to you
• Check any piece of equipment or item that you will be transporting that has been outdoors in the quarantine area.
• Do not park under trees.
• Keep your windows rolled up at all times.
• Before moving between sites within the quarantine area or leaving the quarantine zone, walk around your vehicle and check closely for any adults and/or nymphs; particularly check in the windshield wiper area, bumpers and around the wheel wells. In fall and winter, also look for egg masses.
• A quick check of the engine compartment would be beneficial.
• If you have time and opportunity, a quick high pressure car wash would be ideal before leaving the quarantine area.

Learn to recognize the Spotted Lanternfly in all of it’s life stages and avoid accidental movement of the pest out of the quarantine zone. Thank you for helping with biosecurity of the Spotted Lanternfly.