Gulf Coast mulch should be avoided

April 02, 2006|By JEFF RUGG - Copley news service

Q: I have heard that I should not buy cypress mulch from Louisiana because it has termites in it. I thought cypress was naturally resistant to such things. This sounds rather strange to me. What can you tell me?

A: You know how after a flood in one area, there is an influx of used cars in other areas? One area's problem of a whole bunch of flooded cars is another area's great deal on bargain cars. A similar situation exists for plant materials after a natural disaster.

After storms, it is common to have an excess amount of shredded tree branches and other landscape materials in the area where the storm hit. Larger logs are often split into firewood-size pieces. After the hurricanes of the past couple of years, there has been an abundance of these materials available from the Gulf Coast states.

Many years ago, an exotic pest called the Formosan subterranean termite was introduced to the New Orleans area. It took about 30 years before it was identified as a problem, so it has spread over a wide area. The termite is mainly a serious problem in southern Louisiana, but it has been found from the Carolinas to Texas as well as in California.


The termite probably came in on infested railroad ties, but is now a pest of buildings. It also resides in live bald cypress, oak, maple and pecan trees.

Moving wood from damaged buildings, pallets, landscape timbers, utility poles and other paper or wood products out of the infested area into uninfested areas can spread the termites. Back in October, the Louisiana Department of Agriculture and Forestry imposed a quarantine on 12 Louisiana parishes. Wooden architectural components in that area can't be sold or used until they are fumigated or heat-treated to kill the termites.

The termite is found in other Gulf Coast states and they are not part of the quarantine.

Landscape materials that have been shredded probably don't have any termites at that time. It is possible that they could get termites by sitting around waiting to be sold, however. Logs, firewood piles and damaged building materials can become termite-infested if left on the ground. The quarantine does not cover these materials.

Louisiana is a large exporter of shredded cypress mulch. The mulch is long-lasting and inexpensive, as it is a waste product from the making of cypress wood items. Cypress trees are naturally rot-resistant and the wood is used for shingles and outdoor furniture. The mulch is often sold in bags in gas stations and other discount store locations.

There are a lot of people against using cypress mulch, shingles and other cypress products because old-growth cypress areas are being logged. The trees take at least 100 years to get to the proper size for cutting. Many areas in Louisiana logged a century ago have finally begun getting back to the proper size.

Ivory-billed woodpeckers need huge areas of the large trees for their habitat, so some people don't want the cypress trees to be cut down again in hopes the birds might come back.

Besides removing the trees, roads or canals need to be installed in the swamps to harvest the trees. This damages the swamps, and damaged swamps are part of the reason there was so much flooding in the Gulf Coast region during the recent storms.

It is a complex situation, since even though many trees came back once, there are a lot more roads, pipelines, cities and people, plus there are a lot less wetlands as they have been drained or not replenished because of river channelization.

In many areas, the trees did not come back and the low-quality grass and scrub areas did not protect the coastline from waves. There is concern the trees won't come back over the next hundred years in the areas they came back the first time.

To answer part of your question, cypress mulch won't likely be infested by the termites, but there are other reasons you may not want to use it.

It is a good idea to use mulch in most landscapes. Composted mulch has been naturally heated to kill many pest organisms, but raw bark mulch could harbor some pests, although it is unlikely.

Another area of the country that has a quarantine for wood products is Michigan, to stop the spread of the emerald ash borer, an exotic beetle that was discovered in the Detroit area. It was probably brought in on wooden packing material from Asia, where it is native. Large areas of Michigan, Ohio and Indiana have been quarantined.

The larvae feed on the inner bark of ash trees. To prevent the spread of the beetle, more than 10 million ash trees have been cut down so far. People have been arrested and fined for moving wood out of the quarantine areas. There are billboards in Michigan that tell people to bring their own marshmallows, but to leave the firewood at home.

It may be best to buy your mulch from local sources. Any potential pests in the mulch would already be in existence in your local region. Instead of bark mulch, you can use composted organic matter and you will get many of the same benefits.

E-mail questions to Jeff Rugg at

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