Benefits of Companion Planting for Apple Trees
Companion planting involves growing different plant species together to create a mutually beneficial environment. This practice aims to enhance the health, productivity, and resilience of apple trees by leveraging natural interactions between plants. It is a sustainable gardening approach that can reduce the reliance on synthetic inputs. The goal is to establish a harmonious ecosystem where each plant contributes positively to the overall well-being of the apple orchard.
Pest Deterrence
Certain companion plants can effectively deter common apple pests, protecting the trees without chemical intervention. Many plants release aromatic compounds that confuse or repel pests like codling moths, apple maggots, and aphids, making it difficult for them to locate the apple trees. For instance, the strong scent of mint can confuse and repel aphids and ants, while chives deter aphids and apple maggots. Some plants also serve as trap crops, drawing pests away from the apple trees to themselves.
Attracting Beneficial Insects
A diverse selection of companion plants can attract beneficial insects, which play a dual role in an apple orchard. Many flowering plants provide nectar and pollen, acting as food sources for pollinators like bees, essential for apple fruit set. These same plants often attract predatory insects, such as ladybugs, lacewings, hoverflies, and parasitic wasps, that feed on or parasitize common apple pests. This natural pest control mechanism helps to manage pest populations, reducing damage to the apple crop.
Soil Health Improvement
Companion plants contribute significantly to improving soil health around apple trees. Some plants, particularly legumes, have the ability to fix atmospheric nitrogen into the soil, enriching its fertility and structure. Other plants with deep taproots, such as comfrey, can break up compacted soil and draw up nutrients from deeper soil layers, making these minerals available to the more shallow-rooted apple trees when their leaves decompose. Groundcovers also help suppress weeds, retain soil moisture, and prevent erosion, fostering a stable and nutrient-rich soil environment.
Disease Prevention
Beyond pest control and soil enrichment, certain companion plants can help prevent diseases in apple trees. Some plants possess antifungal properties that can reduce the incidence of common fungal diseases like apple scab. Chives, for example, are known to deter apple scab and other fungal issues, potentially due to the sulfur compounds they release. A healthier soil environment and reduced pest pressure, both benefits of companion planting, also contribute to the overall resilience of the apple tree against various pathogens.
Beneficial Companion Plants for Apple Trees
Herbs
Herbs are particularly valuable companions for apple trees due to their strong aromatic properties and ability to attract beneficial insects. Their distinct scents can mask the apple tree’s presence, deterring pests, while their flowers provide resources for helpful garden visitors.
Chives are known for their antifungal properties, helping to prevent apple scab and other fungal diseases. Their strong onion-like scent also helps to repel aphids, apple maggots, deer, and rabbits from the apple trees. Planting chives in a ring around the tree’s trunk can create a natural barrier against these common garden nuisances.
Garlic, similar to chives, deters aphids, spider mites, and other pests with its potent aroma. It also possesses antifungal properties, which can help protect against soil-borne diseases and apple scab. Garlic’s shallow root system means it does not compete significantly with the apple tree’s deeper roots for nutrients.
Comfrey is a “dynamic accumulator” because its deep taproots draw up nutrients like calcium, potassium, phosphorus, and magnesium from the subsoil, making them available to the apple tree when its leaves are “chopped and dropped” as mulch. This perennial herb also helps retain soil moisture and suppress weeds.
Borage is effective at attracting pollinators, particularly bees, which are essential for apple fruit set. It also deters tomato worms and cabbage worms, potentially benefiting the broader orchard ecosystem. Borage is considered to improve soil health by accumulating trace minerals.
Nasturtiums serve as a trap crop for aphids, drawing these pests away from the apple tree, and can deter codling moths. Their vining nature provides a living mulch that suppresses weeds and helps retain soil moisture around the tree’s base. The flowers and leaves are also edible.
Mint, with its strong menthol scent, repels pests such as aphids and ants by confusing them. It also attracts pollinators, aiding in fruit production. However, mint is known for its vigorous spreading habit, so planting it in containers around the apple tree is often recommended to prevent it from becoming invasive.
Basil repels pests like aphids, spider mites, and mosquitoes, while simultaneously attracting beneficial pollinators. Its fragrant leaves are believed to enhance the flavor of apples and create a more pleasant orchard environment.
Coriander can deter aphids and attracts beneficial insects, including tachinid flies, parasitic wasps, and hoverflies, which prey on pests. It is also thought to enhance the growth of nearby plants.
Yarrow attracts pollinators and predatory insects like ladybugs and lacewings, which help control pests such as codling moths. Yarrow’s deep roots can also loosen soil and bring nutrients to the surface.
Parsley attracts predatory insects, particularly when its flowers appear in the second year. These insects help control pests, including codling moths.
Sweet alyssum, a low-growing flowering plant, attracts beneficial insects like hoverflies, whose larvae feed on woolly apple aphids. Its shallow roots and compact size mean it does not compete with apple trees for nutrients.
Flowers
Flowering plants not only add beauty to the orchard but also play a functional role in pest management and pollination. Marigolds are widely known for their pest-repelling abilities, deterring nematodes, aphids, and beetles. Their strong scent creates an “aroma cover” that can confuse pests. They also attract beneficial insects.
Calendula attracts beneficial insects, including predatory insects that help control pest populations. Its vibrant blooms also add aesthetic appeal to the orchard.
Sunflowers can attract pollinators and may provide some shade in hot climates, which can be beneficial for young apple trees. However, ensure they are not planted so close as to compete for resources or cast excessive shade on mature trees.
Daffodils, when planted in a ring around the base of apple trees, can deter rodents, including voles, from gnawing on the tree bark. Their early spring blooms also provide an early nectar source for pollinators.
Chamomile protects apple trees from harmful bacteria and fungi due to its antibacterial and antifungal properties. It also attracts a variety of beneficial insects, such as hoverflies, beneficial wasps, ladybugs, and honey bees, which help control pests and pollinate apple blossoms.
Chrysanthemums are effective insect-repelling companion plants. They help keep a wide range of pests away from apple trees and other garden plants.
Vegetables and Groundcovers
Certain vegetables and groundcovers provide significant benefits by improving soil structure, adding nutrients, suppressing weeds, and retaining moisture. Legumes, such as peas and beans, are excellent nitrogen fixers. They convert atmospheric nitrogen into a usable form in the soil, which enriches soil fertility for the apple trees. Peas and beans can also be trained to climb structures near the trees, maximizing vertical space.
Leafy greens, like lettuce and spinach, can be planted in the shade cast by apple trees. They act as a living mulch, suppressing weeds and helping to retain soil moisture.
Radishes and carrots, with their deep roots, can help aerate the soil around apple trees, improving drainage and nutrient access. Beets also grow well with apple trees due to different root depths, minimizing competition.
Clovers, including white clover and crimson clover, are effective nitrogen fixers, improving soil fertility for apple trees. They also serve as an excellent groundcover, suppressing weeds and retaining soil moisture. Clover flowers attract pollinators and pest-eating insects, contributing to a healthier orchard ecosystem.
Strawberries are compatible with apple trees and can be grown as a groundcover beneath them. They act as a living mulch, suppressing weeds and conserving soil moisture. Strawberry plants can attract beneficial insects that aid in apple pollination. Their root systems occupy a different soil layer than apple trees, reducing direct competition.
Plants to Avoid Near Apple Trees
While many plants offer benefits, some can be detrimental to apple trees and should be avoided in their vicinity. These plants can compete for resources, host shared pests or diseases, or even release chemicals that inhibit apple tree growth.
Competition for Resources
Certain plants can compete heavily with apple trees for water and nutrients, hindering their growth. Large shade trees, for example, have extensive root systems that can outcompete apple trees for essential resources, particularly water and nutrients.
Grass, often grown directly up to the trunk, is a heavy feeder that competes significantly for water and nutrients, making apple trees more susceptible to diseases and pests. It is generally recommended to clear grass at least a foot or two from the apple tree trunk, or even out to the drip line, to reduce competition.
Root crops like potatoes, carrots, and beets can also compete for nutrients and water. Their cultivation can disturb the soil around the tree’s roots, inhibiting growth.
Shared Pests or Diseases
Some plants can host common apple pests or diseases, acting as reservoirs that can spread issues to the apple trees. Cedar trees, particularly Eastern red cedar (Juniperus virginiana), are a primary concern due to their role in the life cycle of cedar-apple rust. This fungal disease requires both a juniper host and an apple (or crabapple) host to complete its life cycle. Spores from galls on cedar trees infect apple leaves and fruit, causing yellow, orange, or brown spots, and can severely weaken susceptible apple trees. Separating these hosts by at least a mile can help reduce infection.
Tomatoes and potatoes are prone to diseases like blight. They can also share pests with apple trees, potentially spreading these issues.
Brassicas, such as broccoli, cabbage, and cauliflower, can also attract pests. These pests might migrate to apple trees.
Allelopathy
Allelopathy is a biological phenomenon where one plant produces biochemicals that influence the growth, survival, or reproduction of other organisms. Black walnut trees (Juglans nigra) are a notable example of allelopathic plants to avoid near apple trees. They release a chemical called juglone, which is toxic to many plants, including apple trees. Juglone is present in the roots, leaves, and nut husks, and susceptible plants may experience stunted growth, yellowing leaves, and even dieback if planted too close. Maintaining a buffer zone of at least 50 feet, and ideally over 100 feet, around black walnut trees is advised to prevent juglone toxicity.
Fennel is another plant known to be allelopathic. It releases chemicals that can inhibit the growth of neighboring plants, making it unsuitable as a companion for apple trees.
Practical Tips for Apple Companion Planting
Implementing companion planting effectively requires careful planning and ongoing observation. These practical tips can help ensure successful integration of beneficial plants around your apple trees.
Site Selection and Spacing
Proper site selection and spacing are fundamental to successful companion planting. Ensure that chosen companion plants do not overcrowd the apple tree, allowing for adequate light penetration and air circulation around the tree’s base. Most companion plants should be placed at least a foot or two away from the main trunk to prevent competition for resources and allow for tree growth. As the apple tree matures and its canopy expands, the drip line will move outwards; companion plantings should ideally be within this area but still allow for maintenance access.
Soil Preparation
Healthy soil forms the foundation for both robust apple trees and thriving companion plants. Before planting, amend the soil with organic matter, such as compost or well-rotted manure, to improve fertility and structure. This provides a nutrient-rich environment that supports the growth of all plants in the system. Ensuring good drainage is also important, as both apple trees and many companion plants are susceptible to root issues in waterlogged conditions.
Observation and Adaptation
Successful companion planting is an ongoing process of observation and adaptation. Regularly monitor your apple trees and companion plants for signs of pests, diseases, or nutrient deficiencies. The specific needs of your garden may change over time, so be prepared to adjust your companion plantings based on what you observe. This allows for a dynamic and responsive approach to maintaining a healthy orchard ecosystem.
Starting Small
For those new to companion planting, it is advisable to start with a few well-researched and proven companions rather than attempting a complete overhaul of your orchard. Begin by introducing one or two beneficial herbs or groundcovers and observe their effects. This incremental approach allows you to gain experience and confidence before expanding your companion planting efforts.
Watering and Maintenance
Consider how companion plants might affect watering schedules and general orchard care. While groundcovers can help retain moisture, some companion plants may have different water requirements than apple trees, necessitating careful irrigation. Regularly check soil moisture levels to ensure all plants receive adequate water. Maintenance, such as pruning or trimming aggressive spreaders like mint or comfrey, may be necessary to prevent them from outcompeting the apple tree or other beneficial plants.