As the temperature drops and frost begins to paint the landscape, many gardeners assume their outdoor chores are finished for the year. However, the cold winter months can be incredibly harsh on your landscape. Freezing temperatures, biting winds, and heavy snow can easily damage or kill even the most resilient plants if they are not properly prepared.
Taking the time to winterize your garden is one of the best investments you can make for the upcoming spring. With a few simple preventative steps, you can shield your favorite perennials, shrubs, and vegetables from the worst of the winter weather. This guide will walk you through the most effective winter gardening tips to protect your plants and ensure a vibrant, healthy garden when the warm weather returns.
Understand Your Local Climate and Plant Hardiness
Before you begin wrapping and mulching, it is important to know your local climate conditions. The USDA Plant Hardiness Zone map is an excellent tool for understanding which plants can survive the winter in your area. Plants rated for your specific zone or colder can generally stay outside with minimal protection.
However, if you are growing tender perennials or plants that are marginal for your zone, they will need extra help. Keep a close eye on your local weather forecast for freeze warnings and frost alerts. Knowing the difference between a light frost (when temperatures dip just below freezing) and a hard freeze (when temperatures drop below 28 degrees Fahrenheit for several hours) will help you decide when to take action.
Hydrate Your Plants Before the Ground Freezes
One of the most common mistakes gardeners make is putting away the hose too early in the autumn. Wet soil actually holds heat much better than dry soil. Moist soil radiates warmth upward during cold nights, which helps keep the roots of your plants warm.
Give your garden bed, evergreen shrubs, and young trees a deep, thorough watering before the first hard freeze. Focus especially on evergreens like rhododendrons, boxwoods, and yews. These plants continue to lose moisture through their leaves during the winter, and if the ground is frozen dry, they cannot replenish that water, leading to winter desiccation or windburn.
Apply a Generous Layer of Mulch
Mulch acts like a warm winter blanket for your garden soil. It insulates the ground, regulating soil temperatures so they do not fluctuate wildly during freeze-and-thaw cycles. This temperature regulation prevents frost heaving, a process where the soil repeatedly freezes and thaws, pushing plant roots right out of the ground and exposing them to freezing air.
How to Apply Winter Mulch
- Wait for the right time: Apply your winter mulch after the first hard frost, when the ground has begun to freeze. If you apply it too early, you might invite mice and other rodents to nest in the warm organic material.
- Choose the right materials: Shredded bark, wood chips, clean straw, pine needles, or shredded leaves make excellent winter mulch.
- Keep the depth consistent: Spread a layer of mulch about two to three inches deep over the root zones of your plants.
- Leave some breathing room: Keep the mulch a few inches away from the trunks of trees and the stems of woody shrubs to prevent rot and pest damage.
Wrap and Cover Vulnerable Plants
Cold winter winds can dry out plant tissues rapidly, while heavy snow and ice can snap fragile branches. Covering your vulnerable plants provides a physical barrier against these harsh elements.
Using Burlap for Shrubs and Small Trees
Burlap is a fantastic, breathable material for winter plant protection. You can wrap delicate shrubs, such as hydrangeas or young evergreens, directly in burlap. Secure the fabric with twine. For larger or more fragile shrubs, drive wooden stakes into the ground around the plant and wrap the burlap around the stakes to create a protective windbreak shield without touching the foliage.
Utilizing Frost Cloth and Row Covers
For vegetable gardens and low-growing perennials, lightweight frost cloths or floating row covers are ideal. These fabrics allow light and moisture to penetrate while trapping heat rising from the soil. Secure the edges of the cloth with bricks, stones, or metal landscape staples to keep the wind from blowing them away.
Avoid Using Plastic Directly on Plants
Never drape plastic sheeting directly over your plants so that it touches the foliage. Plastic traps moisture underneath, which can freeze against the leaves and cause severe cold damage. If you must use plastic, construct a frame using stakes or wire hoops so the plastic does not touch any part of the plant.
Caring for Potted and Container Plants
Plants growing in pots and containers are far more vulnerable to winter cold than those planted directly in the ground. Because their roots are elevated above the ground, they lack the natural insulation of the earth.
If you have potted plants that are hardy to your zone, you can still protect them with a few clever strategies:
- Group them together: Move your outdoor containers to a sheltered location, such as against the south or west side of your home, and cluster them tightly. This creates a microclimate that traps warmth.
- Bury the pots: If you have space in your vegetable garden or an empty flower bed, dig a hole and sink the entire pot into the ground up to its rim. Cover the top with mulch. This uses the earth to protect the roots.
- Wrap the containers: Wrap the pots themselves in bubble wrap, burlap, or old blankets to insulate the root zone. You can also place the pots inside larger boxes and pack the gaps with straw or crumpled newspaper.
- Move tender plants indoors: Tropical plants, citrus trees, and tender succulents must be brought inside a greenhouse, garage, or your home before the first frost.
Dos and Don’ts of Winter Gardening
To keep your garden safe and thriving all winter long, keep these practical dos and don’ts in mind.
Do:
- Do gently brush heavy snow off branches: Use an upward sweeping motion with a broom to remove heavy, wet snow from evergreen branches before they bend and snap.
- Do leave ornamental grasses and seed heads: Leaving these intact provides structural interest in the winter garden, offers food for winter birds, and protects the crown of the plant.
- Do clean and store your tools: Winter is the perfect time to clean, sharpen, and oil your garden tools so they are ready for spring.
Don’t:
- Don’t prune in late autumn: Pruning stimulates new growth. This new growth is highly tender and will be easily killed by the first hard freeze, putting unnecessary stress on the plant. Save your major pruning for late winter or early spring when the plants are dormant.
- Don’t fertilize late in the season: Just like pruning, applying fertilizer in late autumn encourages soft, new growth that cannot withstand freezing temperatures. Stop fertilizing by late summer.
- Don’t walk on frozen lawns: Walking on frosted or frozen grass can break the grass blades and damage the crown, leaving brown footprints that will remain visible well into spring.
Frequently Asked Questions
When is the best time to cover my plants for winter?
You should cover your plants when a freeze warning is issued, or when temperatures are predicted to drop below 32 degrees Fahrenheit. It is best to put covers in place during the late afternoon before the temperature drops, which helps trap the warm air around the plant.
Do I need to water my plants during the winter?
Yes, if you experience a dry winter with little to no snowfall. Check your plants, especially evergreens and newly planted trees, during warm spells when the ground is not frozen. If the soil is dry, give them a light watering during the warmest part of the day.
What should I do if a plant suffers frost damage?
If you notice limp, black, or brown leaves after a freeze, do not panic, and do not prune them off immediately. The damaged foliage actually provides a layer of insulation for the rest of the plant against future freezes. Wait until spring, when new growth begins, to prune away the dead wood and leaves.
Can I use cardboard boxes to protect my plants?
Yes, cardboard boxes make excellent temporary covers for small plants during a sudden frost. Simply place the box upside down over the plant and weigh it down with a heavy stone. Remove the box the next morning when temperatures rise above freezing so the plant can get sunlight and air.
Winter gardening is not about active growth; it is about preservation and protection. By taking these simple steps to water, mulch, wrap, and shelter your plants, you can shield your landscape from the harshest winter weather. When spring finally arrives, your garden will reward your hard work by waking up healthy, strong, and ready to bloom.