Denny's Soapbox

Cover the Ground With Common Sense

I’m constantly reading various articles this time of year touting the many benefits of mulch and its use in your landscape for the spring.

• Mulch inhibits weed seed germination on the soil it covers. It does not stop new weed seed from germinating in the mulch itself.

• Mulch does hold soil moisture in. That’s the last thing our landscape needs this spring. We need for all the excess moisture in our soil to leave and the soil to dry. This could take a couple of weeks of relatively dry weather.

• Mulch does help some to moderate winter cold and summer heat but really not enough to brag about.

The number one reason any of us mulch our landscape is the appearance. A fresh application of mulch looks great especially the real dark or black stuff. One mistake many homeowners make is the assumption that “all mulch is the same, some just sell it for more money than others”. Wrong. The quality of mulch varies tremendously from one source to another. This is especially true with what’s termed ‘shredded hardwood’, the number one selling mulch. The term ‘shredded hardwood’ can include the shredding of the actual hardwood of trees, wooden pallets, or old building lumber, and anything else that contains cellulose. It could also include bulking agents such as sawdust, ground up yard waste, and crumb rubber. I like to refer to these additives as ‘hamburger helper’. Most of these hardwoods have also been color enhanced using various dyes. Most plain or painted hardwood mulches lose that dark color within six months of application.

100% real bark mulches, whether chipped or shredded are the best and the most costly. They hold their natural color for a year or more. Chipped bark comes in different size chunks so you can choose the size most appealing to you.

Pine straw is making inroads on tri-state landscapes. It has been the number one source of mulch down south for years. Pine straw is easy to apply, stays in place on slopes, and doesn’t compact together like other shredded mulches. Chunk type bark mulches do have a tendency to float during heavy rains and on slopes. Place a thin layer of pine straw down first and then place your bark chips on top. The chips stay locked in place. Check out pine straw’s appearance on TV at the Master’s Golf Championship next weekend from Augusta.

Rubber mulch, edging, and tree rings are showing up at many retailers. It’s being marketed as Eco friendly, recycling millions of tires. The mulch, ground-up rubber tires, is promoted as non-toxic, latex free, does not compact or blow away. The jury however is still out. Research being conducted at the Puyallup Research and Extension Center at Washington State University has concluded something very different. Their findings to date conclude that rubber mulch

• is not as effective as other organic mulches in controlling weeds

• is highly flammable and difficult to extinguish once it’s burning

• is not permanent, like other organic substances, it decomposes.

• is not non-toxic, it contains a number of metal and organic contaminants with known environmental and/or human health effects.

• does float in heavy rain, especially on slopes

Final Note

Make sure whatever mulch you choose, you keep it loose so water and air can always penetrate down to the soil. Never allow any mulch to lie against the stems or trucks of your plants. Pull back the mulch a couple of inches and the total depth should be no more than two inches. The only exceptions would be bark chips and pine straw which do not compact and naturally stay airy. These always let air and moisture through to the soil.