For most of us, when the first frost or snow hits here in the Midwest, it's time for hibernation. All the plants have been brought inside, the fall outdoor decorations are thrown into the compost pile, and the outside is just a meer thought until spring. But, the outside plants still need some TLC. Sure, they are hardy and can handle Mother Nature's cold months, but it's important that they are still being watered. Watered.... it's winter, why should I water my plants? Contrary to popular belief, many plants that do not make it to spring in our climate, in turn, is because of a lack of water, not due to the cold temperatures. It may seem strange to gardeners but watering new plants (and even some well-established plants) in the winter is and should be a new horticulture norm here in Kansas City.

Caring for your outdoor plants and winter greenery is simple and the results can help ensure longevity and health.

Outdoor Plants

When the ground starts to freeze, the roots of plants cannot take up moisture, regardless of the amount of snowfall. Because of this, the plants use the moisture stored in the stems and leaves as a part of the transpiration process. Transpiration is the process of water movement through the plant, and its evaporation from its aerial parts (stems, leaves, and flowers). Keep in mind, that plants only utilize about 0.5-3% of the water it takes up from the soil for growth and metabolic purposes, the rest is lost due to transpiration. With increasingly warmer wintertime temperatures and less snowfall in KC, the transpiration process on plants continues for a longer period now than it did many years ago, which is the reason why winter watering is so important. When a plant transpires more water than what’s available, desiccation starts to occur. Desiccation is the removal of water from a plant, resulting in injury or death. When plants don’t have a supply of water to replenish itself, it becomes desiccated.

Greenery

Evergreens are especially susceptible to desiccation, as they do not drop their leaves for the Winter. Aside from proper watering practices (watering the plant thoroughly before the ground starts to freeze and checking for moisture as the ground thaws again) using an anti-desiccant, also called an anti-transpirant is recommended. In essence, this product helps slow the transpiration process during the winter months, helping reduce the plants from losing moisture through the leaves or needles. Evergreens such as holly, boxwood, rhododendrons, and azaleas, and evergreen magnolias like Brackens Brown Beauty, D.D. Blanchard and Edith Bogue are susceptible broadleaved evergreens that benefit from the use of anti-desiccants. Some conifers can benefit from its use as well, such as cedars, arborvitae, juniper, and pines. Avoid using on conifers like blue spruce, which has a waxy cuticle on the needles occurring naturally.

As when using any horticultural product, be sure to check the label and follow all instructions properly. Here’s the ways to get the best protection for your plants with when using an anti-desiccant:

  • Apply to your plants when the temperature starts to drop consistently below freezing. It’s best to apply during the day, that is above freezing, with no rain or snow in the forecast for at least 24 hours. This allows the product to dry on the plant. Avoid sprayer the plant during freezing temperatures, as this can cause damage to the plant.
  • Do not spray conifers until FULLY DORMANT, generally in mid to late winter. This will prevent trapping excessive moisture in the needles which can burst when frozen.
  • People have also had some degree of success using an anti-desiccant on harder to cultivate deciduous plants such as old fashioned roses and hydrangea for wintertime stem protection.

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