Companion planting techniques discourage harmful pests and encourage the presence of beneficial insects in the organic garden. Companion planting improves soil conditions, provides plants with nutrients and increases disease resistance. Some companion plants even improve the growth rate and flavor of fruits and vegetables. A number of plants are appropriate as pear tree companion plants.
According to Doug Foulk and Emily Hoover of the University of Minnesota, established pear trees require little annual fertilization; nitrogen is the only nutrient pear trees require annually. Utilize companion planting techniques to meet that need. Plant nitrogen-fixing green beans and peas as pear tree companion plants. Plant seeds at the base of the tree and allow them to climb the tree for support. These companion plants capture nitrogen from the air and affix it into the soil. Plant peas and beans a few weeks before transplanting flowers and herbs. The seedlings need time to grow.
Apple maggots, codling moths, Japanese beetles, nematodes, plum curculios, whiteflies and wooly aphids are common pear tree pests. They interfere with the overall healthy growth of the tree and may harm developing fruits. Plant marigolds to deter pests and keep soil free from nematodes that interfere with the health of the pear tree. Plant pansies to repel Japanese beetles. Nasturtiums repel wooly aphids and white flies while attracting beneficial predatory insects that feed on pests. Plant Sweet Alyssum to act as living mulch that shelters beneficial insects such as wasps and hoverflies in the organic garden. Alyssum's sweet-smelling blooms attract bees needed for pollination.
Plant borage as a pear tree companion plant. Borage attracts bees and adds trace minerals to soil. The nutrient and mineral-rich leaves are a great addition to a compost pile or used as organic mulch. Borage increases disease- and pest-resistance in pear trees. Plant Chamomile to attract hoverflies and wasps to fend off pests. This companion plant accumulates calcium, potassium and sulfur. As it enters its dormant stage, it releases them back into the soil. It improves the overall health of anything planted near it in the organic garden. Plant chives as pear tree companion plants to prevent apple scab. While it takes up to three years for chives to accomplish this, garlic will do the same thing sooner. As a companion plant, garlic also repels ants, aphids, borers, codling moths, Japanese beetles, root maggots and spider mites. Garlic accumulates sulfur. Sulfur is a naturally occurring fungicide that prevents disease in many fruit trees, including pear trees.