How to Winterize Blueberry Bushes - the 1 Key Task to Do

A cluster of ripe blueberries growing on a branch — (Image credit: Getty Images/urbazon)

Blueberries are low-maintenance fruit bushes producing highly nutritious, tasty berries. Some varieties can tolerate extremely low temperatures, but all blueberry bushes have one thing in common: shallow root systems. This means mulching becomes a winter task to keep them safe and prospering.

Mulching when you grow blueberries provides multiple benefits. It protects roots from freezing temperatures, while also improving the soil to suit the blueberries' needs. Do this key task each late fall or early winter, and your plants will be healthy year after year and provide a bountiful crop.

Here is how to winterize blueberry bushes quickly using only mulch, which you can do in many climates, though some plants may need a bit more attention. Be prepared to mulch blueberries in the ground and in pots – the latter of which need extra protection for winter, which we cover here too. A bag of pine bark mulch, like this one at Lowe’s, is a perfect mulch for blueberries.

Mulch Blueberries Thickly to Protect the Roots

Blueberries are very cold-hardy fruits, but their exact tolerance depends on the variety. The hardiest, northern highbush, can tolerate temperatures below -20°F and is suitable for colder regions. At the other end of the scale, southern highbush blueberries can get damaged once temperatures go below freezing, and are better suited to climates with milder winters.

When you plant blueberries, they will always need protection for their first winter in the ground, as the plants will not be fully established. Going forward, even hardy blueberries can reap the rewards of a layer of winter mulch to protect the plant’s shallow roots. A layer of mulch each fall insulates the soil from freezing, retains moisture, smothers weeds, and provides essential nutrients as it breaks down.

Because most of a blueberry's root system is in the top 12 inches of soil, it is vulnerable to deep winter frosts and to drying out in summer.

The addition of organic matter as mulch each year gives them a buffer against the cold – which is vital if you live in climates with deep winter frosts – and improves the soil structure, allowing it to hold onto more moisture at the warmer times of year.

Blueberries prefer acidic soil, with a pH around 4.5-5.5. You can help create the ideal conditions for them by using certain types of mulch each winter.

Mulching with pine bark, pine needles, or wood chips (such as this Miracle-Gro wood mulch at The Home Depot) helps to make the soil more acidic. It won’t dramatically lower the pH alone, though, so it is recommended to test the pH of the soil every few years (get a soil test kit at Amazon) to make sure it is right for your blueberries.

Spread a layer 3-4 inches deep right out to the drip line – the circle on the ground underneath the bush’s branches. But leave a small gap a few inches wide around the base. When you pile the mulch against the stem, it usually leads to rot over winter.

If you grow blueberries in a climate that gets extremely cold winters, you can give plants an added insurance policy against the cold by wrapping them in frost cloth or burlap. You can get horticultural fleece at Walmart to protect plants from frost.

You Must Protect Blueberries in Pots

Growing blueberries in pots is an achievable way for anyone with alkaline soil to cultivate the fruit. You can grow the berries in containers filled with ericaceous compost (available on Amazon) and get a harvest of blueberries to enjoy.

However, while bushes in the ground can tolerate freezing temperatures, it is a different story in pots. You always need to winterize blueberry bushes in containers, as the roots are far more susceptible to cold and frost than when growing in the ground.

Depending on your garden and climate, it may be as simple as moving pots together for winter against a protected wall where they can benefit from a warmer microclimate.

Alternatively, you can mulch over the surface of the soil and wrap the pots in frost cloth, burlap, or use winter pot covers, such as the pot protection bags on Amazon.

However you winterize blueberry bushes in containers, always raise them off the ground with pot feet to ensure the pots drain well over the colder months. You can get a pack of rubber pot feet at Walmart.

What to Shop

To encourage new growth and get a blueberry bush to fruit strongly, you do want to prune blueberries each winter. However, it is not a job for early winter. Instead, do it in late winter or early spring, just before the plant is starting to wake up for the new season.

If you want new bushes to add to your collection, you can do two jobs at once and propagate blueberries from hardwood cuttings at the same time as pruning the plants.

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Drew has worked as a writer since 2008 and was also a professional gardener for many years. As a trained horticulturist, he worked in prestigious historic gardens, including Hanbury Hall and the world-famous Hidcote Manor Garden. He also spent time as a specialist kitchen gardener at Soho Farmhouse and Netherby Hall, where he grew vegetables, fruit, herbs, and cut flowers for restaurants. Drew has written for numerous print and online publications and is an allotment holder and garden blogger. He is shortlisted for the Digital Gardening Writer of the Year at the 2025 Garden Media Guild Awards.