Introduction
Controlling weeds is considered to be the one of the most significant problems for many blueberry growers. This article discusses both in-row and inter-row weed management.
In-row Mulching and Weed Control
Controlling Weeds is considered to be the one of the most significant problems for many blueberry growers. It is particularly important to control aggressive perennial weeds and undesirable perennial grasses that grow by producing many underground stems, called rhizomes. Quack grass, Johnson grass, and Bermuda grass are examples of grasses that spread by rhizomes and should be killed before you plant blueberries as they can be a major invasive problem.
Organic mulching material to a depth of about 4 inches (usually sawdust or ground bark) is needed for good production. Irrigation is also a requirement. Blueberries are grown generally on mulched, raised beds in clay soils such as those in Kentucky. Raised beds help provide adequate drainage. Raised beds also help reduce the occurrence of soil and water-borne diseases. Thick organic mulches provide weed and disease suppression, soil temperature regulation, slow-release of nutrients, and moisture conservation. Water management is of paramount concern because blueberry roots lack root hairs they are not efficient in water and mineral absorption.
It is critical to maintain a weed-free zone around blueberries so the blueberry plants do not have to compete with the weeds for water and nutrients. Researchers have determined that an optimum weed free zone around the blueberry plant during the first years of growth should extend roughly 1.5 to 2 feet on each side of the plant. This translates to a 3- to 4-foot-wide, weed-free row bed.
Inter-row Management
As already mentioned blueberries do not have extensive root systems. As a result, clean cultivation of row middles to control weeds and to incorporate cover crops can be done with little damage to blueberries. One should not till deeper than 3 inches if tilling is necessary. Sodden middles that do not contain grasses that spread by rhizomes and are generally not competitive with the blueberry crop are very good and provide inter-row living mulches that can be mowed to add nutrients back to the soil. Mowing, usually three to five times each year, is the usual means of controlling weeds and other vegetation in these sodded middles. Dandelions are perennial weeds that are "good weeds" to allow growing in the sodded middles because they have long tap roots and bring up nutrients from deep in the ground. When mowed these nutrients become available to the blueberry plants. It is important that weeds not be allowed to produce seed and thus perpetuate the weed problem. Fescue is sometimes used for sodded middles, as are several other grass species.
Summary
Controlling Weeds is considered to be the one of the most significant problems for many blueberry growers. Both in-row and inter-row management of weeds is important in blueberry fields.
