When To Winterize Your Gardens. The best time to start winterizing gardens is after the first hard freeze in the fall. A hard freeze occurs when the temperature gets below freezing overnight, killing off tender annual plants and vegetables.
Some perennials, like hostas, peonies and daylilies, need to be pruned in fall to avoid winter damage. Plants like these should be pruned after the first few frosts in late fall or early winter. Other perennials like mums and coneflowers are better off being pruned in spring just before new growth comes in.
Also, do not cut back hardy perennials like garden mums (Chrysanthemum spp.), anise hyssop (Agastache foeniculum), red-hot poker (Kniphofia uvaria), and Montauk daisy (Nipponanthemum nipponicum). Leave the foliage. It's important to protect the root crowns over winter.
Once the first hard freeze has occurred, apply 2 to 4 inches of straw, pine needles, hay, compost, leaves, bark chips or other organic mulch evenly around the plants.
Mulching gardens is the easiest way to protect plants. Plants with shallow roots or young and tender perennials are most at risk to the freezing weather and mulching is the standard and critical tool to protect the plants against frigid conditions.
One way to do this is to dig a trench eight to 12 inches deep, line it with leaves, then cover with soil. Next spring, plant your rows adjacent to the amended soil. Then in fall, dig leaves into the harvested rows and leave the amended soil untilled in anticipation of planting the following spring. Cover soil.
While many gardeners believe that fall cleanup is the only way to go, there are actually several benefits to leaving a majority of cleanup for the spring. Since many animals and insects are adapted to use plants for winter survival, it makes for a healthier garden to keep their needs in mind.
Between 28 and 25 degrees. A hard freeze should severely damage or kill most of your annual flowers — even your hardier flowers that are happier in chillier temps.
Leave Leaves for Wildlife
Fallen leaves also provide wildlife, especially pollinators, with some winter cover. Bees, moths, butterflies, snails, spiders, and dozens of arthropods and pollinators overwinter in dead plant material for protection from cold weather and predators.
2. Perennials and shrubs that are in your zone or one colder can be overwintered in an unheated garage, buried in the ground, or transplanted. 3. Perennials and shrubs in containers will need water through the winter but should not be kept wet.
Plants and perennials that require additional protection to survive your winter will need a deep layer of mulch added by mid November or later, when the ground is beginning to freeze. Do NOT add deep mulch too early or your plants will not be slowly exposed to colder temperatures, allowing them to acclimate for winter.
Thoroughly Water plants if it's not going to rain before the freezing temperatures arrive. It may sound illogical. However, a moist ground stays warmer than dry soil. Watering the night before the freeze comes will insulate the root structure of the grass and plants and decreases the potential for cold injury.
When the weather forecaster warns of an overnight freeze, cover your plants with burlap, an old sheet or blanket, or clear plastic. Use stakes or another support to keep the covering from directly touching the plants.
A fabric covering is best because it will allow moisture to escape while still protecting your plants from frost. Fabric coverings will prevent the freezing air from coming into direct contact with the moisture on the plant while also capturing the heat that is radiating from the ground.
The easiest way to protect from a freeze is simply by covering plants with a sheet or a blanket. This acts like insulation, keeping warm air from the ground around the plant. The added warmth may be enough to keep a plant from freezing during a short cold snap.
It's common to think that everything should be chopped down to the ground in the fall, but some perennials actually need their foliage to protect new shoots through the winter. Other varieties offer up important habitat for local wildlife and some perennials provide height and interest through the winter months.
When to Cut Back Hostas. As a general rule, hostas should be cut back in the late fall. Start with leaves that have wilted or turned brown. Healthy leaves can stay a bit longer to help the roots store needed energy.