Weed and Vegetation Management

Mulches contribute significantly to weed control if constructed and maintained properly. Even without the benefit of weed control, blueberries grow well under mulch because they are shallow rooted and lacking root hairs. A layer of mulch over the soil conserves soil moisture for blueberries. Gooseberries, currants, and elderberries are less likely to benefit directly from mulches compared to blueberries, but given the dearth of herbicides labeled for use in these crops, mulches may be essential to achieve weed control goals.

Mulches are usually constructed from sawdust, bark, wood chips, wood shavings, compost, and woven fabrics. Mulches made from these plant materials or compost are usually applied in a 2 to 4 (sometimes 6) inch layer after planting and will suppress emergence of most annual weeds. As the mulch matures, it may eventually become a haven for annual weeds. Perennial weeds will soon dominate if only using plant material mulches; therefore, it is imperative that perennial weeds be controlled before the crop is planted. An alternative is fabric weed barriers. These are costly, but if amortized over 10 to 12 years, may prove cost effective when considering accrued benefits, particularly in organic systems. Polyethylene mulches are less expensive but are not recommended because they restrict water movement to the roots and may promote surface rooting, making blueberry plants more susceptible to drought stress.

Flailing or mowing Frequently mowing improved turf grasses or perennial sods improves water infiltration and drainage in blueberry aisles. Vegetation between rows of other berries is mowed or flailed.

Herbicides Choose combinations of practices including herbicides that act together to achieve your desired level of vegetation management within berry plantings. Herbicides must be applied as directed on the label (time and rate), otherwise excessive herbicide residues may be present on fruit and jeopardize marketability, or crop injury may occur. DO NOT increase delivery rates of herbicides by slowing tractors or walking speed when there is a large patch of weeds. Slowing or stopping to wet-down the foliage of weeds (for example, Stinger herbicide applied to thistles) may cause excessive herbicide rates that may damage the crop.