Companion planting utilizes the natural characteristics of different species to enhance the growth, health, and productivity of a shared space. Strawberries and asparagus are an excellent combination for this technique because they are both perennial plants with complementary growth patterns. This pairing allows gardeners to maximize the output from a single bed over many years. Understanding their unique biological needs and interacting life cycles ensures a continuous harvest from early spring through early summer.
Understanding the Symbiotic Relationship
The primary reason asparagus and strawberries thrive together is their vastly different root structures, which minimizes competition for water and nutrients. Asparagus is a deep-rooted perennial, developing extensive underground crowns that can reach depths of 5 to 6 feet, drawing resources from the lower soil layers. Conversely, strawberry plants are shallow-rooted, utilizing the top 6 to 12 inches of soil as they spread via runners. This vertical separation allows both plants to exploit different zones of the soil profile, essentially occupying separate ecological niches within the same physical space.
Beyond the root systems, their seasonal growth habits also align to create mutual benefits. Asparagus spears are harvested in early spring. Once the harvest ends, the plant is allowed to “fern out,” growing into tall, feathery stalks. This dense foliage provides light, dappled shade for the low-growing strawberries during the hotter summer months, helping prevent scorching and maintaining soil moisture. The strawberry plants, in turn, act as a natural ground cover, effectively suppressing weed growth that would otherwise compete with the asparagus crowns.
The dense, low-lying strawberry foliage helps to reduce the need for constant weeding around the asparagus, a task that can otherwise be disruptive to the shallow asparagus roots. There is also a slight pest confusion benefit, where the presence of one plant may help deter certain pests from attacking the other. This biological partnership results in a more stable, productive, and low-maintenance perennial bed that produces two different harvests from the same plot of land.
Preparing the Shared Planting Bed
Establishing a successful shared bed begins with preparing the soil, which must accommodate the slightly different, yet overlapping, requirements of both plants. While both asparagus and strawberries prefer rich, well-draining soil, their preferred pH ranges differ: strawberries favor slightly acidic soil (pH 5.8 to 6.5), whereas asparagus prefers a more neutral to slightly alkaline environment (pH 6.8 to 7.5). A compromise pH around 6.5 is often achievable and allows both to grow successfully, especially with the addition of ample organic matter.
Asparagus crowns require deep planting, typically in a trench 8 to 12 inches deep and wide, with a mound of soil created in the center to drape the roots over. This deep planting is crucial for the perennial root system and ensures a long lifespan for the asparagus bed. The trenches are then gradually filled in as the spears emerge throughout the first year.
The strawberry plants are installed between the asparagus crowns along the row or in the spaces between the rows. Strawberry crowns should be planted much shallower than the asparagus, with the crown positioned exactly at the soil surface to prevent rot. A common spacing guideline is to place two strawberry plants between each asparagus crown. Asparagus should be spaced 18 inches apart, with rows 2 to 3 feet apart. This arrangement ensures the strawberries can quickly spread as a ground cover without competing with the newly planted asparagus.
Managing Different Growth and Harvest Cycles
The long-term management of the bed requires recognizing the distinct life cycles of these two perennial crops. Asparagus is a very long-lived plant, often producing for 20 to 30 years. It requires a period of root establishment, with the first significant harvest usually occurring only in the third year after planting crowns. The harvest of the spears takes place over a short window in early spring, after which the plants must grow their tall, fern-like foliage to store energy for the following year.
Strawberries, in contrast, are shorter-lived perennials, with most varieties needing replacement or renovation every three to four years. They produce a harvest much sooner than asparagus. Harvesting the fruit typically begins in late spring or early summer, following the main asparagus harvest. This staggered schedule allows the gardener to focus on one crop at a time.
Watering needs require careful monitoring, as asparagus demands consistently deep moisture to support its extensive root system. Strawberries need consistent, shallower watering to keep their surface roots hydrated. In the autumn, the asparagus ferns should be cut back when they turn brown to prepare the crowns for winter dormancy. The strawberry bed is typically mulched heavily at this time to protect the plants through the winter and keep the spring fruit clean. Managing the strawberry runners is also important; some runners should be allowed to spread to maintain ground cover, but excessive runners must be thinned to prevent overcrowding and maintain access to the asparagus rows.