As we transition to late fall it is time to take a look back and evaluate the impact winter weather has had on our landscape in previous years. Too often we forget that the trees, shrubs, vines, and turf that make up our landscape are living, breathing organisms with cells, tomatoes, and xylem and phloem pathways which carry nutrients from the roots to the buds and back again. The weather conditions we experience during our winter season have a significant impact on the health of our landscape plantings.
Temperature plays an enormous role in the health of our landscape. Sudden temperature changes,extreme cold,harsh winds,and lack of insulating snow were common occurrences this past winter. Given these harsh conditions,we should anticipate some serious damage to plants in the landscape.
When we have sun and mild temperatures in the early part of the winter, it causes many flowers or leaf buds to open prematurely. When these buds opened in response to warm temperatures and bright sun the tender new foliage and flowers were then exposed to bitter cold, snow and ice which followed. Many species of trees, shrubs, and vines will essentially give up on this set of damaged buds and start anew for the spring with a brand new bud set. However this takes an incredible toll on the health of the tree as the tree then has to use much of its stored energy reserves to push out and support this new set of buds. This will lead to many plants that will be stressed and susceptible to secondary pest and insect problems this spring.
The Common Winter Concerns for Your Landscape Plantings
Wind desiccation occurs when trees and shrubs are exposed to dry, cold sweeping winds. Moisture from stems and leaves are drawn out of the leaf and stem tissue, causing cells in the leaves and stems to break down. The results of this are leaves that have a brown cast on the whole leaf or on certain sections of the leaf. Stems could have a puckered look and may be discolored. Plants that are constantly exposed to winds should be given protection by applying an antidesiccant or constructing a wind barrier in late November.
Leaf Scorch/Reflective Damage
Leaf scorch/reflective damage occurs when plant parts not covered by snow are exposed to reflective sunlight from the snow. The light intensity causes a burn on exposed leaves and needles. Usually you will see this towards the bottom of the plant just above the snow line. Anti-desiccants and screen barriers can be used to deflect some of this intense light.
Salt damage can occur from municipalities applying salt to roadways. This can damage plants in two ways. First, when salt and snow melt, passing cars create a spray which coats leaves and stems. The salt draws the moisture out of the cell tissue causing brown spots on broadleaves or brown tips on needled evergreens. Secondly, salt works its way into the root systems of plants and causes damage to root hairs, which are vital to nutrient and water uptake. A good habit to develop is when the weather in early spring gets warm, hose down your plants and soak the soil thoroughly to dilute salt buildup from the winter.
The damage has occurred, what should I do? Now that we know some of the causes of winter damage, where do we start? The first reaction by homeowners is that plants are dead and need to be removed. Although this may appear to be the case, many of your trees and shrubs are actually alive and will bounce back. The first step is to be patient…Many plants that have winter burn need to have their first flush of growth (new leaves emerge). This occurs anywhere from mid-may to mid-June, depending on the variety. At this point you will be able to tell what needs to be pruned. There will also be some plants that do not come back at all. Homeowners that use gardeners should convey this to them so that the plants in question are left alone and not severely pruned or pulled out.
Many Homeowners also feel the need to help the plant and start fertilizing. Unfortunately, fertilizing in the spring does not get to the root system in time to help the plant get out of the damage from the winter. That's why late fall fertilization is critical for winter survival. The fertilizer works its way into the root system and is available for the plant when the plant actively starts growing again. Preparation in the fall will be your best step in making sure winter damage is minimal and your plants bounce back faster after a severe winter. Remember, you just have to wait!!!
The following is a quick list of broad leaved plants to expect winter damage on:
(Click on Planting for Available Pictures on Types of Damage)