Companion planting is a gardening technique where different species are grown near one another to provide mutual benefits, which can include pest control, attracting pollinators, or improving soil health. Applying this method to the blueberry patch can significantly enhance the health and productivity of the bushes by creating a supportive micro-ecosystem. Finding the right plant partners is an effective strategy to maximize fruit yield and ensure the long-term vigor of your blueberry plants. This process requires understanding the specific needs of blueberries and identifying plants that complement those requirements rather than competing with them.
Essential Environmental Requirements
Blueberries have specific environmental needs that dictate which companion plants will be successful. As members of the Ericaceae family, they thrive in highly acidic soil, with an optimal pH range typically between 4.5 and 5.5. This low pH is necessary because it maximizes the availability of essential nutrients like iron and ammonium nitrogen, which the blueberry plant absorbs most efficiently.
The plants also require a soil structure rich in organic matter, which helps to retain moisture and provides a favorable environment for the symbiotic mycorrhizal fungi necessary for nutrient absorption. Although blueberries need consistent moisture, they have shallow root systems and are sensitive to waterlogged conditions, making well-drained, sandy or sandy loam soil essential to prevent root rot. Maximum fruit production occurs when the bushes are planted in a location that receives ample sunlight.
Companion Plants That Share Acidic Soil Needs
Many ornamental and edible plants naturally flourish in the same acidic conditions required by blueberries, making them excellent companions that do not compete for soil pH balance.
Ornamental Companions
Plants like azaleas and rhododendrons, also members of the Ericaceae family, are well-known for their preference for low pH soil and provide aesthetic value with their vibrant spring blooms. These shrubs share similar soil requirements and can create a visually appealing, unified landscape when planted alongside blueberry bushes. Heather (Calluna) is another low-growing shrub that flourishes in acidic soil and full sun, offering continuous color without competing with the main crop.
Edible Companions
Other edible berries, such as cranberries and lingonberries, are naturally suited as companions because they require nearly identical acidic and moist growing conditions. Cranberries are closely related and integrate seamlessly into the blueberry patch, sharing the need for well-drained, organic-rich soil. Strawberries can also be suitable companions, as their shallow root systems do not aggressively compete with the blueberry roots, and they appreciate the same acidic soil and full sun exposure.
Ground Cover
Certain low-growing herbs and ferns also tolerate the blueberry environment well. Ferns like the cinnamon fern or royal fern thrive in acidic soil and can provide ground cover, which helps shade the shallow blueberry roots to maintain soil moisture.
Plants That Offer Biological Support
Other companions are chosen for the active, functional benefits they provide to the blueberry bush, not just shared soil needs.
Attracting Pollinators
Plants that attract pollinators are highly beneficial, as many blueberry varieties rely on cross-pollination for a high yield. Bee balm (Monarda didyma) and native wildflowers like coneflowers or lupines are excellent choices. They attract a variety of bees and butterflies, boosting pollination activity when blueberry flowers are in bloom.
Pest Deterrence
Herbs with strong scents often serve a protective role by deterring common pests. The pungent aroma of alliums, such as chives, onions, and ornamental garlic, can help repel pests like Japanese beetles and aphids from the berry patch. Similarly, herbs like mint and sage release aromatic compounds that can confuse or deter insects, though mint should be grown in a container to manage its aggressive spreading habit.
Soil Improvement
Some plants actively improve the soil environment for the blueberry roots. Specific varieties of clover, such as crimson or white clover, are known for their ability to fix atmospheric nitrogen into the soil, acting as a natural, slow-release fertilizer. Marigolds are another functional companion; some varieties, particularly French marigolds, help control harmful nematodes and other soil-dwelling pests through compounds released from their roots.
What Not to Plant Nearby
It is important to know which plants will actively harm the health or productivity of the blueberry bush.
Any plant that requires an alkaline or high-pH soil is incompatible, as it may counteract efforts to maintain the correct soil chemistry. This includes many common garden vegetables and herbs that prefer a neutral to slightly basic pH, such as asparagus, most brassicas (cabbage, broccoli), and nightshade crops like tomatoes.
Plants that are heavy feeders or have aggressive root systems should also be avoided because they directly compete with the shallow-rooted blueberry bush for limited water and nutrients. Common turfgrass, for instance, can quickly deplete the soil of moisture near the blueberry roots. Finally, certain trees, particularly black walnuts, should not be planted near blueberries because they produce a toxic chemical called juglone, which is harmful to members of the blueberry family.