Here, as everywhere, winters vary yearly and from area to area. Winter can be long, it can be short, it can be relatively mild, and it can be bitter. There are winters with heavy snow and with little snow.
Winter can come very early and suddenly; it can be late and come gradually. In addition, winters in the North are accompanied by all the varied hazards of weather that account for injury and winter killing of plants.
- Winter Hazards For Northern Gardeners
- Protective Mulch in Cold Climates
- Standard Method For Wintering Garden Roses
- Winter Protection For The Eastern Gardeners
- Burlap Wrapping
- Winter Protection For Tender Plants
- Winter Injury
- Winter Protection For Southwest Gardeners
- Winter Protection For Western Gardeners
- Protection Against Climates
Winter Hazards For Northern Gardeners
Gardeners in the North, therefore, must protect their plants from all kinds of hazards—drying winds, drought, sunscald, sudden and extreme changes in temperatures, excessive moisture, lack of snow cover, winter thaws, and intense cold.
Because of these unfavorable winter conditions, hardy perennials, biennials, and bulbs should be attempted to be overwintered in the garden.
These should be given a protective mulch consisting of at least six inches of tree leaves or marsh hay placed soon after winter starts (usually sometime in November).
Frost should have penetrated a few inches into the soil, and temperatures should have dropped to 15° degrees Fahrenheit before protective mulches are applied.
These should be removed as soon as winter is over (usually not until early April). Most varieties of garden chrysanthemums cannot be relied upon to survive winter here, even with the protective mulch mentioned.
To be sure of their overwintering, dig a clump of each kind and store it in a cold frame (could be a temporary one made with boards set on edge), cover it with leaves or hay 12” inches deep when freezing weather occurs, and keep this mulch dry by covering it with a sheet of waterproof paper.
Protective Mulch in Cold Climates
Shrub-type evergreens, especially newly planted ones, and all new plantings of trees and shrubs should be mulched like garden plants.
The trunks of young, smooth-barked trees and all newly planted ones should be wrapped with a spiral wrap (purchased from your nursery or garden store) to protect them from sunscald and rodents.
Standard Method For Wintering Garden Roses
The standard method for wintering garden roses is to hill soil over the base of the plant about a foot high in late October and cover it with a 12 to 24-inch mulch of leaves or hay after freezing weather.
Canes are tied together at the top or bent over and covered. Canes of climbers are laid on a cushion of leaves and then covered with leaves or hay. Open-end cans containing poison mouse bait should be placed next to the canes.
Winter Protection For The Eastern Gardeners
Winter protection varies all over our area— even from one garden to the next; what works one year may be a failure the next. It’s always a gamble!
Adequate soil drainage is very important, especially in spring. Installation of lines of agricultural drain tile may be required.
Frequent freezing and thawing damage many shallow-rooted plants and newly planted ones. A 2 to 3-inch mulch will often reduce this type of damage. Any available organic material may be used.
However, plants with green tops (foxgloves, for example) may be rotted by covering the leaves themselves. Shading alone with evergreen branches may be sufficient to save them.
Mulching is best not done until after the ground freezes. In most instances, the greatest advantage of a mulch comes after early January.
Burlap Wrapping
Wind does more harm than suspected. Wrapping with burlap is ugly but often effective for evergreens and broadleaf evergreens.
It is less unsightly to plant out of the wind in the lee of a house or twiggy shrub or evergreen that can take it.
Mounding soil around roses is a nuisance but usually pays off. Try chopped corn cobs or peat. Lack of drainage, however, is the cause of much damage when heavy soils have to be used.
Trees planted within the last year have not become sufficiently established to withstand winter sun and wind on trunks. Wrap with burlap or sisal paper from the ground to the branches.
Leave this on for two years. To control borers, paint trunks with DDT and mix in water to the consistency of coffee cream.
Winter Protection For Tender Plants
Climbing roses can be protected in colder climates by burying the tops or wrapping them in straw, covered with burlap if you can take the unsightly mummies.
Some tender plants, such as blue and pink hydrangeas (H. macrophylla) may be covered with leaves held in place by chicken wire.
Since winter drying kills many plants, water very heavily during November until the soil is soaked to a depth of at least 12” inches. This practice alone may save many evergreens and other plants.
Hardy flowers received too late for planting in the garden can be potted or planted in a cold frame. Cover them with a 4- to 8-inch layer of straw or oak leaves.
Small seedlings and recently rooted cuttings are best left in their flats or pots, sunk in the soil of a cold frame and covered with a thick, airy mulch.
Winter Injury
Kinds of winter injury fall into two main categories: frost injury and winter killing.
Frost
Severe injury or death results from freezing temperatures in the fall before plants are “hardened” by periods of moderate cold. Twigs may die back, or entire trees and shrubs may be killed.
Injury is most common on young plants with thin, smooth bark, which continues active growth late in the fall.
Winter Killing
The type and severity of injury caused by low winter temperatures vary with the species, variety, and age of the plant, degree of dormancy, state of vigor, soil moisture, type, and condition of the root system.
Winter Protection For Southwest Gardeners
Winter protection in this area is not a major problem owing to our relatively mild temperatures.
However, there is an occasional sudden low dip in temperature. Hot-cold extremes in very short periods give our area the most concern.
In the west part of this section, drying winds howl across the plains and constitute a major threat to gardens.
As a result, practically every garden is enclosed with a fence or wall to break the wind and prevent soil loss by wind erosion.
Light Mulch of Straw Manure
Light mulches of strawy manure that are kept moist give adequate protection to most plants at ground level. A 2-inch layer of shredded manure provides just the right heat for pansies to bloom all winter!
Roses, one of the major plant groups, are treated in a variety of ways. The general practice is slightly hilling up (4” to 5” inches). This is followed by applying strawy manure to fill the valleys created by putting the soil up around the plants.
This manure should be kept moist to keep it from blowing. Late winter drops in temperature that come after roses have started to bud are a real problem.
Large paper sacks may be pulled over each plant, and the ends covered with loose soil. This will protect roses for several days.
A fine mist sprayed over the whole will cause a sheet of ice to form, further insulating the plants. Plastic bags from dry cleaners will make just as effective a covering.
Control Sunscald
A limited amount of sunscald occurs on newly planted trees or those less than two years out of the nursery. Wrapping with burlap strips or tree wrap for this purpose will prevent this damage.
Often, newly set smaller plants can be protected by placing a board or shingle on the south and west sides of them to break the wind or cast a shadow.
Changes in Temperature
The most damage occurs in this area through sudden and extreme temperature changes. Last February, a 40-degree drop in 24 hours occurred in Norman, Oklahoma.
What protection can man provide for plants against this? Very little. Nature usually gives a big assist in the form of snow or sleet that insulates the soil surface and the plants.
Watering
The best overall protection that man can provide is adequate water at all times. Dry freezes penetrate the soil and cause extensive damage to the roots and the plant’s death.
Moisture in any form is good protection against extreme winter conditions.
Winter Protection For Western Gardeners
Farm windbreaks are an important asset in making growing good gardens in the High Plains easier.
Windbreaks reduce winds all year, which causes the drying of plants. In addition, they catch snow.
Proper planning of tree belts is necessary so that snow piles in the right places; good snow cover is a real asset to perennial plants, not to mention the extra moisture it stores up for the garden.
Temporary Windbreaks
Temporary windbreaks (snow fences or rows of sunflowers, for example) serve similar purposes.
A cover of twigs and branches or a rough plow job in fall can catch more snow and protect tender perennials.
Protection Against Climates
The West’s special problems include protection against dry, open winters, intense cold, sunscald, drying winds, and hot-cold extremes.
Protect against dry, open winters by thoroughly watering trees and shrubs in late fall or winter.
Shingles for small plants or burlap covers supported on poles for larger ones serve as wind barriers to protect new plants just set out in the past growing season.
Plant-only hardy varieties are recommended for this area to combat the intense cold. Good snow cover reduces damage; mulches help, as does complete covering with soil, such as is done with raspberry and rose canes.
Protect fruit trees susceptible to sunscald by using low-branching training and pruning methods. Grow ornamental trees to bush form if they are prone to sunscald.
Wrapping with kraft paper, whitewashing the bark, and board covers to protect the southwest part of exposed trunks are other helpful practices. Damage usually occurs in late winter.
Break drying winds using windbreaks; rely on mulches, and don’t overlook anti-desiccants such as Wilt Pruf.
To fight hot-cold extremes, again, rely on mulches; remember that north and east slopes are less changeable than the south and west ones.
Winter Protection For Tender Roses
Tender roses like hybrid teas must be covered in this area for best results. Do not prune canes in the fall.
Mound the plant’s crown with soil to 6” inches. Place wire fences around the plant; tie canes if necessary. Fill fences to a height of 12” inches with hay, straw, or leaf litter.
Canes will stick out beyond the mulch and will winterkill, but they offer protection to the lower part of the plant. Cover tender climbing rose canes entirely with soil, as you would raspberry canes.
Winter Protection For Broadleaf Evergreens
For the few broadleaf evergreens successfully grown here, the wooded, shaded site usually chosen will offer the kind of winter protection needed.
Winter Protection For Biennials and Perennials
Cover tender biennials and perennials with straw or marsh grass. Apply in late fall after a few light frosts.
Mulch Cover
A mulch cover is recommended for tender bulbs and for late-planted tulips to help them make a good root system before the soil freezes deeply.
Planted early in the fall, tulips, squills, grape hyacinths, and many lilies normally require no mulch protection. If growth tends to start too early in spring, don’t be hasty in removing mulch.
44659 by Robert A. Phillips
44659 by Victor H. Ries
44659 by Robert H. Rucker
44659 by Leonard A. Yager