BioCycle April 2005, Vol. 46, No. 4, p. 28
Color durability appears to be driving demand for colored mulch products. Brush and pallet processors are investing in equipment to supply the market.

BOSTON Bark Corporation in Waltham, Massachusetts got its start in 1991, primarily as a reseller of bark products. The company had a small operation where it received leaves and brush, and purchased bark from outside vendors. “The leaves and brush were loaded onto the live floor trailer that brought in the bark and hauled away,” recalls Vincent Mula, company owner. “Then we would resell the bark.”
Mula owned a company that was involved with road construction and site development. He was knowledgeable about heavy equipment and soils, which ultimately led the initial bark selling and green waste transfer operation into composting and mulch production. “About seven years ago, we took over the operation of a site owned by the city of Waltham used to stockpile leaves and brush. They would have an outside hauler take it away. I visited a number of composting sites, and worked with a composting consultant, and we set up our windrow composting operation on the land owned by the city.”
The site receives all of the city’s leaves – about 18,000 cubic yards/(cy)year; it also brings in 14,000 to 15,000 cy/year of leaves it receives from landscapers and other sources. Leaves are shredded with a Bandit Beast 3690 grinder; an additive manufactured by Global Odor is mixed in with the water used in the grinder’s dust suppression system and sprayed onto leaves as they are being shredded. The additive suppresses odors and accelerates decomposition of the leaves. Windrows are turned with Caterpillar loaders six or seven times over the next nine to ten months. “By August or September, the material is ready to screen,” he notes. “We use a CEC vibrating deck screen.”
Boston Bark has a two-acre retail site in the center of Waltham. Compost is sold in bulk – both wholesale and retail – along with about 25 other soil and landscaping products. Landscapers coming to purchase products can also tip separated loads of leaves and brush. Those materials are taken to the compost and mulch production site for processing.
MOVING INTO COLORED MULCH PRODUCTS
Brush received from city operations as well as at the retail site are ground and put into windrows. After about four months, the material is mixed with bark that the company purchases from other vendors. Several years ago, noting customer demand for colored mulch products, Boston Bark purchased another vendor’s product to sell through its retail operation. “We made a delivery to a customer, unloading material in the driveway,” recalls Mula. “It rained, and turned the driveway red. We had to clean the driveway, and realized that if we wanted to sell colored mulch, we should make it ourselves.”
Mula purchased colorants from T.H. Glennon Co., and received help on how to work with the dyes. Initially, he says, “we would shovel the colorant onto a pile of premixed material and mix it in. We used this ‘cave man’ method for about a year, and produced about 2,000 to 3,000 cy of colored material. We were satisfied with the quality of the material. Recently, we purchased a Bandit Color Critter, which attaches to our grinder. We are now producing about 10,000 cy/yr of colored product, which we sell at the retail location.”
Boston Bark makes two types of mulch using pine bark, its processed brush and a small amount of compost. “Our dark blend, which is almost black, uses very little colorant because the product is already fairly dark,” Mula explains. “We also produce a burgundy, almost mahogany-colored mulch.” A third product, derived from the dark blend, is triple ground then screened through the CEC equipment. It is about three-eighth to half-inch minus. “A lot of landscapers and homeowners like to use this fine pine product around flower beds,” he adds.
Initially, Mula shied away from selling colored mulch products because he felt customers would purchase less mulch overall as the colored material would not need to be replaced as frequently due to the fact that is sustains its color over time. “What we found over the past two to three years, however, is that the material sustains its color, but needs to be replenished every year,” he notes.
NEW LIFE FOR SHIPPING PALLETS
Ten years ago, Les Irvine, owner of Irvine Wood Recovery, had not planned to enter the mulch making business – much less start coloring the material. But a decade later he is doing just that – producing and shipping 25,000 yards of color-enhanced mulch to customers throughout the Cincinnati, Ohio area. “Originally we were in the forklift business – and everywhere there is a forklift, there is a pallet,” says Irvine. “A couple of our customers had mentioned that they had scrap piles of pallets building up. When I heard that a couple of times, I looked into it a little bit more.”
He purchased an Olathe Pallet Chipper that could be towed behind a chip-truck the company used to haul the shredded pallet waste. Customers who were used to having pallets hauled away in open topped containers welcomed the on-site service, and Irvine’s business grew. And as it grew, so did the mound of shredded wood waste. Irvine began investigating ways to reprocess the wood in order to get rid of it – and got into mulch production. Chipped wood is double-ground in a tub grinder, then screened with a Fecon Satellite screen to remove the overs. Magnetic head pulleys on the tub grinder and stacking conveyors remove nails.
“We were mixing the mulch with a high nitrogen compost and selling it as an industrial grade mulch,” says Irvine. “That was not as popular as the rich, plush bark mulches, and we started to see coloring going on throughout other parts of the country. So we started looking into the whole process.” What he found was that color-enhanced mulch was gaining in popularity due mainly to its ability to maintain a rich color longer than traditional bark mulches.
Irvine purchased a Fecon Batch Mix coloring unit. Ground material is loaded into the machine with the paddle wheels turning to fluidize the material. Colorant is injected into the mixing chamber along with water. The wood, colorant and water mixture is continuously turned by the paddle wheel for the duration of the cycle time (about five minutes, depending upon batch size and particle size range). “It does about 60-plus yards per hour, typically in 5 to 6 yard loads,” he says. “We can grind and color at the same time with two workers or we can color and load a truck with one person.”
Initially the product was “going to landscapers who were doing commercial work – big office buildings, banking institutions, stand alone buildings like McDonalds and Burger King,” he adds. “But we’ve seen more residential work in the last year. Our landscapers might do a yard in a new neighborhood and the neighbors will say ‘Hey, where’d you get that.’ They love the fact that it holds its color so much longer than regular bark mulch. So the landscapers come back for more.” – N.G.
Jim Wahl contributed to the information on Irvine Wood Recovery for this article.