For plants, making it through the winter can be a chilling process. Read below to learn how plants deal with the long- winter months.
by Tina Graver
If you are a plant, the first step to dealing with the cold is to go dormant! Environmental signals that trigger dormancy include the shortening of the day length, as well as cold temperatures. By early fall, most plants have slowed their growth and began to set winter buds. Once the temperature starts falling, many plants will drop their leaves. Why? Leaves are responsible for the movement of water through the plant. They act like a straw, suctioning water from the roots out through the top of the tree. Dehydration is more risky and damaging to a plant than the cold itself so the ability to conserve water through leaf drop provides a survival advantage under harsh conditions.
Going dormant and dropping leaves aren’t the only tricks plants have to make it through the winter. There are many unseen processes happening inside the plant. A little-known fact – plants have unsaturated fats that help protect them from freezing.1 The more unsaturated fats a plant can produce, the more resistance it has to freezing. Some plants also have the ability to undergo deep super-cooling and survive temperatures as low as – 40 degrees F. 2 Super-cooling occurs when ice crystals form inside the cells of the plants, and are stored in extracellular spaces where they cannot damage critical parts of the plant’s cells. Even more surprising, cold temperatures can trigger the plant to make its own brand of anti-freeze! 3
What about plants that keep their leaves? The leaves of evergreen trees and shrubs are much thicker and have a ‘waxy’ coating. These characteristics help the plant reduce water-loss in the winter time. Staying evergreen is a useful adaption over dropping leaves because it gives the plant a head-start on making food once the weather breaks.
A synthetic ‘waxy’ substance can be applied to plants to aid in the reduction of water loss. These sprays are known as anti-desiccants and are especially useful for helping transplanted trees and shrubs survive through the cold and dryness of the winter months. Our plant health care specialists at Mead Tree & Turf Care are available to assess the needs of your plants for surviving the winter.
1,2,3 Raven et al. (2005) Biology: Seventh Edition. McGraw-Hill Companies. Pg 814; 827
by Tina Graver
When the leaves fall from the trees, and lawn mowing is a distant memory, most homeowners put their yards on the back burner until spring. However, there is a lot that can be done to assure that spring doesn’t bring some unpleasant surprises when it comes to your favorite plants due to over-wintering insects, harsh weather conditions and deer.
Dormant Oil Sprays
control overwintering pests
protect from winter-burn
protect from chewing and rubbing
Dormant oil sprays
Horticultural oil is a material approved by the Organic Material Research Institute (OMRI) and poses few risks to people or most desirable species, including beneficial insects such as lady bugs. Horticultural oil works by coating the air holes through which insects breathe, causing them to die from asphyxiation and is excellent at safely controlling certain types of over-wintering pests. Armored and soft scale insects are target pests, as well as mite and aphid eggs that overwinter in cracks and crevices of woody plants. The ideal time to apply is in late fall or early spring when day-time temperature hover around 55 degrees.
Anti-desiccant sprays protect plants from excessive water loss through the leaves and soft buds. The combination of cold drying wind, fluctuating temperature from very cold to warm and sunny causes what is known as ‘winter burn.’ Plants suffering from winter burn will have brown needles or leaves. An important point is that anti-desiccants do not protect the plants from freezing. Vulnerable plants include most broadleaf evergreens and shrubs such as hollies, boxwood and nandina. The spray coats the foliage, preventing moisture loss. The coating should be applied when temperatures are above freezing for at least 24 hours. The coating wears off at temperatures above 50 degrees and may need to be re-applied throughout the winter.
While deer can be an issue all year round, they can cause significant damage in the winter months when food sources become scarce. There are many methods for protecting plants from hungry deer. One option is to install temporary deer fencing or trunk wraps to act as a physical barrier. This kind of barrier may be used alone or in conjunction with deer repellant sprays and bittering agents. Deer repellant sprays are often derived from predator urine such as coyote. These sprays tend to be offensive to many customers and we will often recommend a bittering agent instead. A bittering agent is sprayed on the foliar of the deer’s favorite plants. The deer may sample one of these plants but will leave it alone once they taste the product.