Strawberry plants produce specialized horizontal stems known as runners (or stolons), which are a form of vegetative reproduction. These structures extend outward from the mother plant’s crown, forming small, genetically identical plantlets at their nodes. Managing runners in the late summer and fall is important because it directly influences the health of the existing patch and the potential fruit yield for the following season.
Deciding Whether to Prune or Propagate
The decision regarding runners depends on whether the goal is to maximize the fruit harvest or to expand the number of plants. If the patch is dense or the mother plant appears weak, pruning the runner is the best course of action. Removing the runner allows the plant to redirect energy into strengthening its crown and developing next season’s flower buds.
Alternatively, gardeners use propagation, allowing runners to root to create new plants. This strategy is necessary for renewing the patch every three to five years, as strawberry plants become less productive with age. Select the healthiest, most vigorous runners from the highest-yielding plants for this purpose. This management usually takes place in late summer or early fall, allowing plantlets time to establish roots before the ground freezes.
Steps for Rooting and Transplanting New Runners
To propagate, select a healthy runner with a plantlet that has developed a few leaves. Encourage the node (where the new plant forms) to root into the soil while still attached to the mother plant. This is achieved by pinning the node directly into the garden soil or into a small pot using a U-shaped wire or landscape staple.
Keep the soil consistently moist around the pinned node to encourage root development. The plantlet draws nutrients from both the soil and the mother plant until its root system is strong enough. After four to six weeks, the plantlet should be firmly rooted and resist gentle tugging.
At this point, sever the runner stem connecting the new plant to the mother plant with clean shears. The separated plant is ready to be transplanted to a permanent location or placed in a temporary winter holding area. Fall transplants need immediate protection from frost and cold to prevent root damage. If winters are harsh, move the small plants into a cold frame or protected, unheated space until spring.
Preparing the Strawberry Patch for Winter Dormancy
Protecting the entire strawberry patch, including mother plants and established runners, is necessary for winter survival. Winterization should occur after the plants have gone dormant, indicated by leaves turning grayish or flopping over, and after several consecutive nights of temperatures around 20°F. Mulching too early prevents plants from hardening off, while waiting too long risks cold injury.
The purpose of winter mulch is to prevent the soil from undergoing repeated freeze-thaw cycles. These cycles cause “heaving,” where soil expansion pushes shallow-rooted crowns out of the ground, exposing them to cold and desiccation. Clean wheat straw is the preferred material because it provides an effective air buffer without compacting the crowns.
Apply the straw loosely to a depth of four to six inches over the plants. This airy layer provides reliable insulation, allowing crowns to survive low temperatures. In early spring, once the threat of severe frost has passed and soil temperatures reach about 40°F, rake off the bulk of the straw. Leave a thin layer behind to suppress weeds and keep developing fruit clean.