Experts tell us weed control is one of the greatest challenges when establishing a new blueberry planting. Weeds compete with blueberry plants for essential water, nutrients and sunlight. Weeds also decrease harvesting efficiency and interfere with maintenance operations. Effective weed control begins six to 12 months before planting by using a combination of pre-plant herbicides and cultivation. Planting rows should be thoroughly prepared and weed-free before blueberry bushes are planted.
A 4-foot wide weed-free strip, centered on the plant row, should be maintained for the life of the blueberry planting. Sod should be established between the rows and maintained by mowing. Centipede grass, carpet grass or some native grasses are better choices than bahiagrass or Bermudagrass, which grow much faster and require higher maintenance.
Cultivation, pre-plant herbicides and mulching can be used to prevent and manage weeds in newly-established plantings. Several herbicides are labeled for use in blueberry production. Always read, understand and follow pesticide label instructions carefully when using any herbicide. Pre-emergent herbicides act by forming a protective layer on bare soil and prevent seedling emergence. They are not effective if applied over organic mulches or heavy leaf litter. Post-emergent herbicides control weeds that have emerged from the soil and are actively growing. Most blueberry growers apply post-emergent herbicides to the desired 4-foot weed-free zone, using a shielded sprayer, to prevent herbicides from coming in contact with the blueberry plants. The safest and most commonly used herbicide in blueberries is glufosinate ammonium. Mulching can assist with weed control during the first few years of the planting. A well-maintained mulch can encourage vigorous growth of young blueberry plants by keeping the soil cool, loose and uniformly moist in the rapidly growing root zone.