Washington State University Extension

Garden Tips


written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

You may have already read or heard about the dire warnings being circulated on the internet alerting gardeners about cheap mulch being sold by home improvement stores. This low-priced mulch supposedly comes from Louisiana and is infested with Formosan termites. These alerts seem to have spread almost as quickly as a computer virus or an insidious computer worm. Gardeners around the country are extremely concerned. Fortunately, this warning is basically a hoax… a myth… the beginning of a new urban legend.

Let’s look at the facts in this situation. The Louisiana Commissioner of Agriculture and Forestry, Bob Odom, points out that his department has quarantined woody debris being removed from termite infested areas. In the quarantined areas contractors are mulching and hauling the waste to approved landfills withing the infested areas.

Each parish (county) in the quarantined areas must first submit a plan for the treatment of the wood before it can be moved out of the area. The Louisiana Department of Agriculture and Forestry is making sure the quarantine is being observed and their invasive pest expert has contacted the stores mentioned in the e-mail warnings regarding the use of such wood in their mulches.

Odom says, ‘In my opinion, someone is using the Internet to cause hysteria about a problem that doesn’t really exist. If there are people out there who know about someone violating the quarantines, then they need to report it to us. We’ll shut the culprits down real quick but it has to be reported.’ He added , ‘I think the quarantines are doing the job, though. We’ve worked with the debris contractors, the Corps of Engineers and FEMA to handle the debris and quarantines.’

I’d like to point out that it doesn’t make much sense for the home improvement stores mentioned in the warnings to ship chipped wood all the way from Louisiana to Washington state or other distant locations. Given the cost of shipping, due to high oil prices, it’s likely the mulch wouldn’t be very ‘cheap’ once it arrived in stores here. It would be much more cost effective to use waste chipped wood and bark from trees in the Pacific Northwest. Also, most gardeners in the region use shredded bark or bark nuggets for mulching, not chipped wood.

Out of curiosity you might want to know about the Formosan termite, sometimes dubbed the ‘super termite.’ It’s a non-native species of termite that is believed to have entered the U.S. sometime after World War II on military ships through southern ports of entry, including New Orleans and Lake Charles in Louisiana, Charleston in South Carolina, and Galveston and Houston in Texas.

The Formosan subterranean termite, Coptotermes formosanus Shiraki, is extremely destructive. One of the things that makes this non-native termite so destructive is the size of its colonies. While native subterranean termites tend to have colonies of about one million termites, the Formosan termite colonies may reach a size of eight million. Like other subterranean termites, the Formosan termites feed primarily on wood, but also on other cellulose containing materials such as cardboard and paper. While they don’t eat other types of materials for nutrition, they will chew their way through insulation board, thin lead and copper sheeting, plasters, asphalt, and some types of plastic in search of food and moisture. While rumored to chomp their way through concrete, they don’t. However, they are very adept at finding their way through tiny cracks and fissures in concrete and mortared walls.

So far, the Formosan termite has only been found in Alabama, southern California, Florida, Georgia, Hawaii, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, and Texas. The cost of control of these destructive pests and the repair of their damage is extremely high. Their destruction has already cost residents of New Orleans over one billion dollars.

This super termite may have entered the U.S. on ships and become established in port regions, but it has been unwittingly spread to other areas by gardeners in infested potted plants, railroad ties and landscape timbers and trees. So while there is no substantive truth in the internet warnings, it’s not a bad idea to think about the things you can do to prevent subterranean termites, either native or non-native, from becoming a problem.

Here are some tips:
– Don’t store wood, cardboard or paper in such a way that these materials are in direct contact with the soil. This also includes wooden planters, posts, tubs, trellises and firewood. When possible anchor wooden posts in cement so that the wood is not in direct contact with the soil.

– Don’t stack firewood close to your house.

– Inspect any wooden items, such as railroad ties, wood mulch, or landscape timbers, before buying them and placing them in your landscape.

– Keep mulch, landscape plants, and wooden structures one foot or more away from the foundation of your home. Don’t use wood chips as a mulch around your home’s foundation.

– Termites need moisture. Fix leaky outdoor faucets and water lines. Slope the landscape away from the house so precipitation and irrigation water drains away from the house. Prevent sprinklers from wetting the walls of your house or other wooden structures. Fix any leaks which can create damp conditions, such as drain drips or roof leaks.

– Look and dispose of any wooden stakes or scrap wood left behind in the soil from construction projects.

– Get rid of any dead wood in the landscape, especially the roots and stumps of trees and shrubs that have been removed.

In the next month or so our native western subterranean termite will be swarming or flying about for the purpose of reproduction and establishment of new colonies. To the untrained eye winged termites look like winged ants. If you suspect you might have a problem with termites, bring a sample of the offending creatures to the Benton County WSU Extension office in Kennewick (5600E West Canal Drive) and we’ll tell you if its ants… or termites.

If you want to know more about termite detection, prevention and control in Washington, you can find the WSU Extension Bulletin ‘Termites” available at no charge on-line at

Published: 3/11/2006 9:01 AM

Garden Tips, WSU Extension, Benton County, 5600-E West Canal Drive, Kennewick, WA 99336-1387, 509-735-3551, Contact Us

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