How To Winterize Strawberry Plants So They Thrive Come Spring

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Strawberry bushes are a hardy perennial variety, thriving in USDA zones ranging from 3 to 10. These resilient plants enter a state of dormancy during the winter months, biding their time until the arrival of warmer spring temperatures, when they commence the development of their delightful, ruby-red fruits. Although cold temperatures can potentially harm flowers and the plants themselves, exposure to frost is crucial for the strawberry bushes to prepare for the upcoming winter. This cold stratification period prompts the plants to enter a dormant state, during which they will initiate the growth of flower buds. In the spring, as temperatures rise, the plant receives the signal to emerge from dormancy. To safeguard these resilient plants from the harsh cold in zones 7 and below, winterization is essential to shield them from extreme cold and to allow the plants to concentrate on maintaining a robust crown and root system.

Winterization is vital to protect strawberry buds from freezing temperatures and to prevent frost heaving, a phenomenon where the cycle of freezing and thawing can push the plant’s crown out of the soil. Proper timing of winter preparations is crucial for a bountiful harvest the following year. It is advisable to wait until there have been several hard frosts in your region, but to act before the ground completely freezes, ensuring the plants have entered dormancy. This typically occurs in November or December, once temperatures have consistently dipped into the 20s for several consecutive nights.

It is imperative to wait until the plants are dormant before winterizing, as covering them with mulch can introduce warmth that could mislead them into thinking it is spring. This could result in buds opening prematurely, which may be damaged or even killed by the cold.

Strawberry bushes are relatively short-lived perennials, with an average lifespan of three to six years. Their runners propagate and generate new offspring, ensuring a continuous supply of new plants in the garden. Older bushes will eventually produce less fruit and will die, with the dead plant turning brown and easily extracted from the soil with minimal resistance.

A dormant strawberry bush retains healthy roots, anchoring it firmly in the ground. You may notice green tissue beneath the crown if you gently peel it back. The leaves will change color to yellow or red, flatten out, and cease new growth. The stems will become brittle and may bend slightly before breaking.

Once you have confirmed that the strawberry bushes are dormant, you can initiate the winterization process. The preparation steps can vary depending on whether the plants are in the ground or in pots.

1. Use a rake to clear away debris such as leaves, weeds, and old mulch from around the beds and the plants.
2. Eliminate any diseased or damaged plants.
3. Trim the plant back to 2 to 3 inches above the crown to remove any dead foliage and runners, ensuring to leave a few sets of new leaves on the crown. You may choose to discard the runners or propagate them, but avoid leaving them on the mother plant as they can siphon energy from it.
4. Approximately one month prior to the anticipated first frost, apply a balanced fertilizer like 10-10-10 (a blend of nitrogen, phosphorus, and potassium, known as NPK) following the label instructions for application details.
5. Water the plants regularly until the first frost.
6. After the first frost, but before temperatures consistently fall below 20°F, add 3 to 5 inches of mulch such as pine needles, straw, or wood chips, and water thoroughly. In a dry winter, water the plants occasionally to maintain the health of the crowns.
7. In the spring, remove the mulch once temperatures consistently remain above 20°F. Mulch placed between plants and rows can remain in place to retain moisture and deter weeds.

Potted strawberry plants should ideally be overwintered indoors to shield them from cold weather. Container-grown plants are more susceptible to freezing as pots offer less insulation than the ground and are exposed to cold air from all directions, which can harm the roots. For winter preparation, follow these steps:

1. Trim off any runners at the base of the mother plant. If the runners have developed roots, they can be planted in separate pots.
2. Remove any dead leaves from the plant, as well as any debris or weeds.
3. Apply 10-10-10 fertilizer or an organic option like blood meal.
4. Move the pot indoors to an unheated garage or basement, or place it against a wall on a covered porch to protect it from the wind.
5. Cover the plants with a layer of mulch such as straw or pine needles, and water to moisten the soil. Wrap the pot with old blankets, burlap, or bubble wrap for additional insulation.
6. While dormant, the plants will require minimal water as they are not actively growing. Water them occasionally to prevent drying out.

In the event that you cannot bring the pot indoors, you can bury the entire container in the ground to provide insulation. Trim any runners and dead leaves from the plant. Dig a hole large enough to accommodate the pot, place the pot inside, and fill in the sides with soil. Treat the plant as you would one grown in the ground, applying fertilizer and water appropriately.