Companion planting involves strategically placing different plant species close to one another to create a mutually beneficial garden environment. This practice supports a healthy ecosystem, where plants work together to thrive. For citrus trees, companion planting can enhance their growth and productivity by fostering a balanced garden.
Benefits of Companion Planting for Citrus
Using companion plants around citrus trees offers numerous advantages that contribute to their overall health and fruit production. One primary benefit is natural pest deterrence, as certain plants attract beneficial insects like ladybugs, lacewings, and hoverflies. These insects prey on common citrus pests such as aphids and mealybugs, reducing the need for chemical interventions. Fragrant herbs can also repel harmful insects, creating a protective barrier around your trees.
Companion plants also play an important role in attracting pollinators, which are needed for citrus trees to produce fruit. Bees, butterflies, and even hummingbirds are drawn to the nectar and pollen of specific companion flowers, improving the cross-pollination of citrus blooms. Beyond pest and pollination benefits, companion plants can enhance soil health by fixing nitrogen, breaking up compacted soil with diverse root systems, and adding organic matter. Groundcovers help suppress weeds, conserving moisture and nutrients for the citrus tree, while also regulating soil temperature.
Top Companion Plants for Citrus Trees
A variety of plants can serve as excellent companions for citrus, each offering unique benefits to support your trees. Herbs are a popular choice due to their pest-repelling qualities and ability to attract beneficial insects. Basil, for instance, deters aphids and mosquitoes while potentially increasing nitrogen levels in the soil. Rosemary attracts predatory spiders and parasitic wasps, and its early blooms can also aid in citrus pollination.
Dill, cilantro, oregano, and parsley attract various beneficial insects, including ladybugs, lacewings, and tachinid flies, which prey on common pests. Chives deter aphids and attract pollinators, while lemon balm attracts predatory insects and repels biting insects.
Flowering plants add beauty and function, often serving dual roles in pest control and pollination:
Marigolds deter nematodes, whiteflies, and beetles through their scent and root secretions.
Nasturtiums act as a trap crop, drawing aphids away from citrus trees, and attract pollinators.
Lavender attracts pollinators and repels pests like mosquitoes and moths, thriving in similar warm, dry conditions as citrus.
Sweet alyssum attracts hoverflies (predators of aphids and Asian citrus psyllids) and provides groundcover.
Yarrow attracts a wide array of insects, including parasitic wasps and ladybugs, and blooms concurrently with many citrus varieties.
Borage attracts bees, butterflies, hummingbirds, and other predatory insects, enhancing pollination and pest control.
Calendula deters nematodes and beetles while attracting beneficial insects.
Legumes, such as peas, alfalfa, and clover, are excellent nitrogen fixers, enriching the soil for nutrient-hungry citrus trees. Clover can also serve as a living groundcover, helping to suppress weeds and conserve soil moisture. Comfrey, while requiring management to prevent overgrowth, attracts pollinators and can be used as a nutrient-rich mulch, contributing to soil fertility.
Plants to Avoid Near Citrus Trees
While many plants offer benefits, some should be kept away from citrus trees to prevent negative impacts. Plants that aggressively compete for water and nutrients, such as tall trees and shrubs, can hinder citrus growth by blocking sunlight and depleting soil resources. Those with high moisture requirements can also leave citrus trees dehydrated, as citrus prefers drier topsoil. Additionally, plants with extensive or aggressive root systems, including many root vegetables like potatoes, can disturb the shallow feeder roots of citrus trees.
Certain plants exhibit allelopathy, releasing chemicals into the soil that inhibit the growth of nearby plants. Examples include Eucalyptus trees, known for exuding oils that can stunt growth, and Black walnut trees, which produce juglone, a chemical toxic to many plants. Fennel is also considered allelopathic and can release compounds that may stunt citrus growth.
Mint, if not properly contained, can spread aggressively through rhizomes, potentially interfering with citrus roots.
Implementing Companion Planting Successfully
Successful companion planting around citrus trees requires careful consideration of environmental factors and proper placement. When selecting plants, ensure they are compatible with your local climate, soil type, and the sunlight requirements of both the citrus tree and the companion plant. Citrus trees prefer well-drained soil and consistent, but not excessive, moisture, so choose companions with similar water needs to avoid overwatering the citrus. It is also important to consider the mature size of companion plants to prevent them from overshadowing young citrus trees or creating dense, air-restricting growth.
Proper placement and spacing are important to prevent competition and ensure good air circulation. It is advisable to avoid planting anything within 15 to 30 centimeters (6 to 12 inches) of the citrus tree trunk to allow for inspection and maintenance. Plants with shallow root systems are preferred directly under the canopy, while those requiring more sun can be placed just outside the citrus tree’s drip line. For citrus grown in containers, planting companions in the same pot is not recommended due to limited space and potential root competition, but nearby pots can still offer benefits.
Ongoing maintenance is also necessary to ensure the success of your companion planting efforts. Monitor the watering needs of companion plants, making sure not to overwater the citrus tree, which prefers its topsoil to dry out between waterings. Regular pruning of companion plants helps maintain their size and prevents them from competing for light or air with the citrus. When using mulch, apply it in moderate amounts, 7 to 10 centimeters (3 to 4 inches) deep, and avoid piling it against the trunk to prevent moisture buildup. Regularly observing your garden allows you to make adjustments as needed, fostering a diverse and healthy environment for your citrus trees.