Companion planting involves growing different plant species close together to maximize garden efficiency and promote mutual health. This technique uses natural interactions to enhance the growth, flavor, and productivity of a target crop. For strawberries, selecting the right neighbors can significantly reduce pest pressure and disease incidence, leading to a more successful harvest. Understanding which plants support strawberries and which ones hinder them is essential for creating a balanced and high-yielding garden environment.
Beneficial Companion Plants
Specific plant pairings offer strawberries support, ranging from attracting beneficial insects to strengthening the plants. Borage is a highly beneficial companion, primarily for attracting pollinators like bees, which improves the fertilization rate of strawberry flowers. This bristly-leaved herb also deters several insect pests and is believed to enhance the flavor profile of the ripening berries.
Planting alliums such as garlic, chives, and onions nearby provides a natural defense against common strawberry ailments. These plants release sulfur compounds that function as natural fungicides, suppressing soil-borne fungal diseases and surface molds like gray mold. Their strong, pungent aroma can also confuse and deter insect pests, including aphids and spider mites. Alliums must be situated carefully to avoid direct competition, as their dense root systems and nutrient demands can interfere with the shallow roots of the strawberries if planted too closely.
Low-growing herbs like thyme can be intercropped effectively around the strawberry plants without crowding them. Thyme attracts predatory insects, such as hoverflies, whose larvae consume soft-bodied pests like aphids, providing natural pest control. Legumes, including bush beans and lupins, are recommended for their ability to convert atmospheric nitrogen into a usable form via a symbiotic relationship with soil bacteria. While strawberries do not directly access this fixed nitrogen immediately, these plants contribute significantly to long-term soil health and fertility.
Plants That Inhibit Strawberry Growth
Just as some plants offer support, others can actively harm strawberries through competition or disease transmission. All members of the Brassica family, including cabbage, broccoli, and cauliflower, should be kept far away. These are heavy nutrient feeders with extensive root systems that aggressively compete for resources. This competition for water and nutrients often results in stunted strawberry growth and lower fruit yields.
Another group to avoid is the nightshade family, which includes tomatoes, potatoes, peppers, and eggplant. These plants share a susceptibility to Verticillium wilt, a damaging soil-borne fungus. If a nightshade is infected, the fungus builds up resting structures in the soil, posing a significant infection risk to the strawberry patch. In strawberries, Verticillium wilt causes the wilting and browning of older, outer leaves while inner leaves remain green, often leading to plant death.
Avoiding planting strawberries in a bed that recently hosted nightshades is important because the fungal inoculum can persist in the soil for many years. Other aggressive plants like fennel are known to suppress the growth of many neighboring species, including strawberries, and should be planted in isolation. Furthermore, strawberries are part of the Rosaceae family, meaning they share disease vulnerabilities with roses and raspberries, which should also be considered when planning a garden layout.
Strategic Placement and Crop Rotation
The physical arrangement of companion plants is equally important as the choice of plants themselves. Beneficial neighbors, such as herbs, should be planted close enough to the strawberry patch to share their aromatic and pest-deterring properties, but not so close that they crowd the crowns. Dense planting of large companions can block sunlight and air circulation, creating a humid environment that encourages fungal diseases.
The placement of the entire strawberry patch must also be considered over the long term, as strawberry plants are perennial and occupy the same space for multiple seasons. Over time, soil-borne pathogens like Verticillium wilt and black root rot build up in the soil, leading to a decrease in berry size and overall plant vigor. Therefore, rotating the location of the strawberry patch is a necessary management strategy.
It is recommended to move the strawberry patch to a new area of the garden every three to five years to break the disease cycle. Allowing the old patch to rest and planting cover crops or non-susceptible vegetables helps reduce the pathogen load before strawberries are replanted. This intentional rotation, combined with the strategic use of beneficial companion plants, supports the long-term health and sustainability of strawberry production.