Kenaf

(Hibiscus cannabinus)

      Is a member of the plant family Malvacea. It is related to cotton and okra, as well as roselle (mentioned below). Kenaf has two leaf conformations, entire or divided. All kenaf plants start life with entire leaves. As they grow, some cultivars start to produce divided leaves, somewhere around the 7th to 10th nodes above the cotyledons.

      Kenaf produces showy hibiscus-type flowers, all domestic cultivars have yellow flowers with red blood spots at the base of each petal, however there is some variation for flower color.


      Flowering is triggered in most types of kenaf by short days (fall conditions). Some varieties developed in Guatemala, are day-neutral, flowering after about 100 days growth. At Starkville most cultivars we test are short-day and start to flower too close to the killing frost to ripen seed. We increase small quantities of seed in the greenhouse during winter months. Larger quantities are purchased from a seed producer in Tampico, Mexico.

      Kenaf produces two types of fiber: Bast - long fibers similar to hemp and flax (linen) derived from the phloem in the bark of the stem. Core (fibers) are those found in the pith (inside the bark) is similar to balsa wood, but denser. Bast fibers are retted to free them from the rest of the plant as well as the non-fiber parts of the bark. Retting can be accomplished by leaving the crop in the field to let natural bacteria and fungi eat away the non-fiber components of the bark.


      Uses of kenaf include: plastics extenders and fiber reinforcement, bio-remediation products, large and small animal bedding, grass and erosion mats, particle-type board, paper, and potting media.

      Harvesting of the crop in Mississippi makes use of equipment likely to be found on a Mississippi farm. There are several methods of harvest that are tailored to different locations around the U.S., but in Mississippi we harvest frost-killed kenaf. The plant is usually killed by freezing temperatures during the first week in December. Harvest of the dry/dead stalks occurs in February or March. The time between December and March allows for dew-retting as the plants stand in the field.

      A forage harvester or corn silage cutter harvests the kenaf stalks, cutting them into short billets from 1 to 3 inches long. The crop is blown into a cotton boll-buggy. The boll-buggy dumps into a module builder and is pressed into a block 9' x 9' x 20' weighing roughly 9 tons. The module is processed at the separation facility at Charleston, MS.


      Next to white-tailed deer, nematodes, especially Southern root-knot nematodes, are the biggest pest on kenaf, causing severe yield reductions. Roots of the plants are characterized by severe galling. Plants lodge or die outright.