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| This Month in the Garden |
1. Plant Hardiness: Understanding
the hardiness of your plants is the first step. Some plants, like pansies and
evergreens, are naturally cold-tolerant, while others are more vulnerable. Use the USDA Plant Hardiness Zone Map to
determine which plants are best suited for your region and which need extra
protection during winter. By the way, here on Long Island we are in hardiness zone 7b. Also, when choosing plants, try to choose those that are cold hardy one to two zones colder than where you live.
2. Monitor Weather Forecasts: Stay informed about upcoming freezes, frost warnings, and temperature drops. Quick action such as covering plants or moving containers can make all the difference in preventing damage. It is the extreme temperature fluctuations that are most detrimental to your outdoor plants.
3.
Mulch for Insulation: Adding
a layer of organic mulch such as wood chips, straw, or shredded leaves can help insulate the soil and roots from extreme temperature fluctuations. Mulch acts like a blanket, retaining warmth in the ground and preventing frost heaving, where repeated freezing and thawing push roots out of the soil. Apply a 2–4 inch layer around the base of your plants but keep it away from the stem to
avoid rot.
4. Anti-Desiccants: Some broadleaved evergreens such as Rhododendron, Azalea, Aucuba, Skip and Cherry Laurel, Holly and Leucothoe (to name a few) lose excessive moisture through their leaves in winter. Applying an anti-desiccant spray can help prevent water loss and protect foliage from drying winds. Anti-desiccant should be sprayed in the late fall/early winter as a preventive before freezing temperatures occur. Follow the instructions on the product label and do not apply when temperatures are going below freezing, as this can do more harm than good and put the plant at risk. With the temperature extremes we have been having, and popularity of certain tropical-like plants such as palms and banana trees increasing in outdoor spaces, anti-desiccant can be a helpful preventive.
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Thermonasty: During frigid days when temperatures reach below 20 degrees, certain broad-leaved evergreens such as Rhododendron, display a unique trait known as thermonasty. This adaptation causes the leaves of the plant to act as a natural thermometer. When temperatures dip below freezing, leaf margins curl inward causing the leaf to roll up and droop. This process reduces the surface area of the leaves, thereby reducing water loss. Also, the narrow, drooping, needle-like leaves help to shed snow, which would otherwise
accumulate and break branches.
5.
Keep your Plants Hydrated: Hydration
is crucial for plants in winter, but overwatering can be just as harmful as
dehydration. Before a freeze, give your sensitive plants a deep watering to ensure the
roots are well-hydrated. This helps the soil retain warmth and protects the
roots from freezing. Avoid watering during freezing temperatures, as it can
lead to ice damage. Watering before a deep freeze works well with outdoor container gardens and should be done before covering the plant.
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6. Frost Heaving: Certain perennials such as Heuchera (Coral Bells) are subject to frost heaving during extreme temperatures. This occurs as the ground freezes, then thaws, then freezes again, causing the roots of the plant to uplift. When this occurs, gently push the crown of the root back into the soil with your foot. If possible, push some extra mulching around the plant for further protection. The mulch will help keep the plants roots and crown in contact with the insulating soil.
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7. Relocate/Cover and Protect Plants: Plants in containers are more susceptible to cold weather because their roots are less insulated. Move pots to a sheltered location, such as a garage, porch, or greenhouse. If relocating isn’t an option, frost
cloths, burlap, or even old bed sheets can shield your plants from freezing
temperatures. Cover delicate plants, such as citrus trees or young or tender shrubs, when
frost is predicted. Make sure the cover extends to the ground to trap heat from
the soil, and secure it with stakes or rocks to prevent it from blowing away.
Avoid using plastic directly on plants, as it can trap moisture and cause more
harm.
8. Avoid Pruning in Winter: While
it’s tempting to prune during winter, avoid heavy cutting as it can stimulate
new growth that’s vulnerable to frost. Instead, wait until late winter or early
spring when the risk of freezing has passed. For now, remove only dead or
damaged limbs to prevent disease. An additional note is to not try to remove frozen ice from the plant. It is best to allow the plant to thaw naturally, as not to damage/break any branches.
9.
Build Wind Barriers: Strong
winter winds can dry out plants and cause damage, especially in areas located near water. Create windbreaks using
fences, screens, or even stacks of straw bales to shield your garden. Place
these barriers on the side of your plants that faces the prevailing wind to
minimize exposure.
10. Build Cold Frames & Cloches: Cold
frames and cloches are great for protecting tender plants or seedlings from
frost. A cold frame is essentially a mini greenhouse, while cloches are
dome-shaped covers placed over individual plants. These structures help to extend the gardening season by trapping heat
and creating a microclimate that helps plants survive harsh conditions. Each method captures the daytime solar energy; thus, heating the surrounding air and the soil floor, while helping to insulate plants. Try to place your cold frame in a sheltered location (as near a structure) and away from strong winds.
Winter doesn’t have to mean the end of your garden’s beauty. By preparing your outdoor plants for freezing weather, you can protect their health and enjoy a thriving landscape come spring. With proper insulation, hydration, and care, your plants will emerge stronger and ready for the growing season.
I hope you enjoyed This Month in the Garden. Be sure to stop by on the 1st. and 15th. of each month as I continue to share gardening tips, information and horticultural adventures! Catch up on posts and other news with my newsletter, Northeastern Gardening News. Subscribe for free to receive monthly updates.
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As Always...Happy Gardening!
Author: Lee @A Guide to Northeastern Gardening, © Copyright 2010-2025. All rights reserved.
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