This Month in the Garden: Winter Gardening: Protecting Your Outdoor Plants from the Cold

Over the last couple of years, temperature extremes during the winter months have taken a toll on our outdoor gardens. From weeks of mild temperatures in the 40's and 50's to cold blasts plummeting temperatures into the teens and even single digits, these extremes pose a risk to plants, and safeguarding them from the harsh cold becomes crucial for maintaining their health. Some broad-leaved evergreens such as Rhododendron will even tell you when temperatures are below 20 degrees. Their leaves will curl in severe cold, a process known as thermonasty, which helps to reduce surface area and conserve moisture. There is a way you can be proactive. Here are some effective strategies to help you protect your green companions during the chilly months.

Choose Cold-Resistant Plants: When purchasing plants, be sure to choose those which can withstand temperatures which are one to two zones colder than your location. Research and select species that thrive in your specific region, as they are more likely to withstand winter conditions. For sensitive plants or those in containers, consider bringing them indoors during extreme cold spells. A garage or enclosed porch can provide a temporary shelter until milder weather returns. For certain landscape plants which are broad-leaved, such as Rhododendron, Azalea, Osmanthus (False Holly), Euonymus, Aucuba, Cherry, Skip and Mountain Laurel, Leucothoe, Boxwood and Holly, the use of an anti-desiccant before winter sets in is recommended. 

Apply Mulching: A layer of organic mulch around the base of your plants will insulate the soil and regulate temperature. This acts as a protective barrier, preventing extreme temperature fluctuations that can be harmful to plant roots. Ideally, the best time to mulch is during late spring to early summer, or early fall. Be sure to mulch way before any sign of frost, as applying at the incorrect time can have the opposite effect and cause harm.

Proper Watering: Adjust your watering routine as winter approaches. Ensure that the soil is adequately hydrated before the first frost, as moist soil retains heat better than dry soil. However, be cautious not to overwater, as waterlogged soil can lead to root rot. With your outdoor containers, give them a good watering before you know there is going to be a severe temperature drop. This will help them to hydrate before the deep freeze.

Watch for Frost Heaving: In freezing temperatures soil around your plants may be subject to frost heaving. This is when ice forms underneath the soil and expands upwards from the ground causing plants such as perennials to push upwards exposing the crown. Heuchera (Coral Bells) and Liriope are especially prone to this type of damage. As a preventive measure apply mulch finishing to your garden beds. To remedy, once the ground thaws, slightly tap the soil back down, and brush the mulch back around the exposed crown of the plant. During the time of frost heaving, avoid stepping into garden beds, as this can cause the soil to become too compact. Compacting the soil too much can have a negative effect on future soil drainage. 

Cover Plants: Stay informed about upcoming weather conditions. Cover plants when extreme temperature drops are predicted. Use protective covers, such as burlap or frost cloth, to shield your plants from frost and freezing winds. Make sure the covers are secured tightly to prevent heat loss, especially during the coldest nights. If you have potted plants, consider moving them closer to the house or clustering them together. This provides additional warmth and protection against the cold. Elevate containers to prevent them from sitting directly on cold surfaces and use frost covering until the freezing temperatures subside. Once the threat of plummeting temperatures has passed, you can uncover the plant and keep the cover nearby. For larger plantings, the use of temporary windbreaks such as wooden or fabric barriers can be used to shield plants from strong offshore winter winds.

Tips on Pruning & Fertilization: As a preventive measure, any dead or damaged branches should be pruned off trees and shrubs before winter sets in. Pruning encourages healthy growth and minimizes the risk of disease. However, avoid heavy pruning in late fall, as it may stimulate new growth that is vulnerable to frost. Adjust your fertilization routine in late fall to promote plant hardiness. Avoid nitrogen-rich fertilizers, as they can encourage tender growth susceptible to frost damage.

The winter months can be quite unpredictable and tend to be more drastic during the months of January, February, and even through March when the seasons are changing. By taking these proactive measures, you can ensure the health and vitality of your outdoor plants. Remember that each plant is unique, so tailor your approach based on their specific needs and the climate of your region.

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! 

Plant your Garden for Spring with my Books!:

A Guide to Northeastern Gardening: Journeys of a Garden Designer Zones 3-9

Landscape Design Combinations

Dream, Garden, Grow!-Musings of a Lifetime Gardener 

Gardening by Month: A Monthly Guide to Planning the Northeastern & Mid-Atlantic Garden

Shade Gardening for the Northeast and Mid-Atlantic

"As Always...Happy Gardening!" 

Author: Lee @A Guide to Northeastern Gardening, © Copyright 2010-2024. All rights reserved.