Protecting Ornamentals from Winter Damage

With colder temperatures and harsher winter weather forecasted and expected later this week and month, homeowners will begin taking additional steps to protect pipes, faucets, automobiles, pets, and other vulnerable items around the home. But during one’s preparation, don’t forget your plants. Each year, many of our landscape ornamental plants suffer various degrees of cold damage due to drastic fluctuations in outside temperature.  One day it feels like spring has arrived and then another day an artic blast roars in reminding us and plants it is still winter.

There are several steps that homeowners can take to help acclimate plants to cold temperatures and protect plants from temperature extremes. These steps range from proper site selection to adjustment of cultural practices.

Every landscape contains different microclimates that are determined by a variety of factors, including elevation, landform, surface reflectivity, soil properties, degree of canopy cover, and proximity of structures or plants. These conditions can cause temperatures to fluctuate from one location to another within your landscape. You should consider your existing microclimates or ways to modify them when choosing the planting site for cold sensitive plants.

Tender plants should be planted in a site with good air circulation, rather than a low area where cold air settles. You can provide barriers to protect tender plants from cold winds by shielding them with adjacent plantings, fences, or buildings. The height, density, and location of a windbreak will affect the degree of wind speed reduction at a given site.

The cover of tree canopies can help reduce cold injury in several ways. Plants in shaded locations typically go dormant earlier in the fall and remain dormant later in the spring. Minimum night temperatures under a tree are higher because the canopy reduces radiant heat loss from the ground to the atmosphere. The shade provided from early morning sun can decrease bark splitting of some woody plants. Plants that thrive in partial shade usually show less winter injury than plants in full sun. However, plants requiring sunlight that are placed in shade will be unhealthy, sparsely foliated, and less tolerant of cold temperatures.

Poor soil drainage can affect cold susceptibility by causing plants to have weak, shallow root systems which are more susceptible to cold injury.

Healthy plants that have had proper nutrition will be more tolerant of cold temperatures and recover from injury more rapidly than plants grown with suboptimal nutrition. Avoid late fall fertilization or fertilization before unseasonably warm periods, which can result in a late flush of growth making the plant more susceptible to cold injury.

Watering landscape plants before a freeze can also help protect plants. Well watered soil is capable of absorbing more solar radiation than dry soil and will reradiate heat at night.

Avoid late summer or early fall pruning which will cause flush of new growth that will be more susceptible to cold injury.

Move container into protective structures where heat can be supplied. Containers that must be left outdoors should be protected by mulch and pushed together before a freeze to reduce heat loss from the sides of the container. However, leaves of large canopy plants can be damaged if crowded together for extended periods.

Plant coverings provide more protection from frost than from extreme cold. Covers that extend to the ground and are not in contact with plant foliage can lessen cold injury by reducing heat loss from the plant and from the ground. Foliage that touches the cover is more easily injured because of heat transfer from the foliage to the colder cover. Some examples of coverings are: cloth sheets, quilts or black plastic. You must remove plastic covers during a sunny day or provide necessary ventilation to release trapped heat.

Tree Seminar

The City of Sylacauga and the Sylacauga Tree Commission will be hosting a seminar on the planting and care of trees on February 15, 2007.  This will be a half of a day seminar and each participant will receive a sugar maple and instructions on how to plant and care for it.  This will be a very informative seminar with speakers from Auburn University School of Forestry and the Alabama Cooperative Extension System.  There will also be a horticulturist on hand to explain how to plant your tree.  Registration is $15 prior to February 1st and $20 after February 1st.  Please make plans to attend this enlightening program.  For more information please contact John Gladness at (256) 401-2426 or Shannon Plexico at (256) 401-2425 or splexico@gmail.com.

For more information, contact the Tallapoosa County Extension Office at 256-825-1050 or visit us online at www.aces.edu.