Green Horizons

Pine straw, the accumulation of naturally shed needles of pine trees, is an excellent landscape mulching material. It is commonly baled and sold in the southeastern U.S., where it is the No. 1 mulch used in landscape plantings. However, loblolly pine, the predominant species used for pine straw plantations in the south, may not be tolerant to the colder conditions in Missouri. Shortleaf, the only pine species native to Missouri, is not well suited to pine straw production due to its namesake short needle length.

That said, many sites in Missouri are suitable for pine straw production, said Chris Starbuck, University of Missouri associate professor of plant sciences. Starbuck and Steven Kirk, MU extension associate in plant sciences, have evaluated the potential of cold-tolerant selections of loblolly pine and pitch x loblolly hybrid pines for production of pine straw in Missouri. These trees have cold hardiness for Missouri with a similar needle length to loblolly. In addition, Starbuck is looking at selections of loblolly found growing in central Missouri.

Pine straw is a multi-million dollar industry, said Starbuck. A well-managed plantation in full production can gross up to $1,000 per acre every other year from the sale of pine straw bales. (From a tree health standpoint, it is best to harvest only a portion of the plantation in a given year to allow trees to benefit from needle accumulation between harvests.)

Since pine straw is actually a leaf (needle), it benefits the landscape in much the same way decomposing leaves benefit the forest floor by recycling nutrients and maintaining soil organic matter. Hardwood bark mulch, on the other hand, when used in excess, can cause a buildup of calcium and potassium in the soil, increasing pH and causing an imbalance in soil minerals that can interfere with nutrient uptake. The minerals in pine needles are balanced so their decomposition does not create an imbalance in the soil. Hardwood and pine bark mulch can wash away in a strong rain. Pine straw knits together and holds in place during heavy rain, helping to prevent soil erosion.

The University of Missouri Center for Agroforestry and the MU department of horticulture are working toward creating a pine straw industry in the state of Missouri through research, product development and education designed to encourage producers, retailers and consumers to adopt the use of this renewable, sustainable, natural mulch material.

Fifteen pine genotypes have been evaluated at the Horticulture and Agroforestry Research Center (HARC) for their potential for pine straw production. A seed orchard is being created from the trees shown to be superior in the study; HARC also may supply the White State Forestry Nursery at Licking, Mo., and other nurseries with seed, Starbuck said. In the near future, Missourians will be able to use the seed created to plant their own pine straw-producing tree plantation, windbreak, alley cropping practice or silvopasture enterprise.

Future pine straw research and demonstration projects may include developing the best management practices for producing pine straw, market research to nurture the fledgling pine straw demand, on-farm demonstrations concerning pine straw production and harvest, demonstrations of pine straw mulch in urban landscapes, evaluation of producing pine straw in a linear windbreak configuration and evaluation of shade tolerant nursery stock to grow between mature pines in a pine straw plantation.

See more information about pine straw production and use – and other agroforestry practices – on the University of Missouri Center for Agroforestry Five Practices DVD. For ordering information, go to http://www.centerforagroforestry.org/pubs/dvdorderform.asp

Find pine straw at Heckemeyer Farms, 206 College Rd., Sikeston, MO 63801, 573-471-8198.