Archives February 2021

Will Live Oaks Survive Freezing Temperatures, Ice, and Snow?

by Texas Tree Surgeons Extreme Weather, Resources, Tree Health Care

Live oaks are a common sight in North Texas. These native trees are well-adapted to our soil and climate, but can still be stressed by extreme weather. Many, if not all, live oaks will show signs of frost damage after a hard freeze. Like other plants, the main symptom will be brown, dead, or wilted leaves. Live oaks may show browning in patches or over a whole tree. 

Luckily, we expect most live oaks to recover from the freeze! The usual live oak leaf exchange in the spring should replace the dead leaves and enable the trees to take up nutrients. New growth may be thin in the coming year, however, because of residual stress. Young live oaks or trees that are already stressed by disease or insect activity may have a harder time recovering. It is important to monitor live oaks as we move into spring and summer to assess their ability to come back. 

The live oak (Quercus virginiana) is a North Texas landscape staple. Hardy and evergreen, live oaks can range in size up to 50 feet tall and 100 feet wide. Live oaks do not drop leaves in the fall, but rather have a leaf exchange in the spring. Once prized for shipbuilding due to their naturally-curved limbs, live oaks are now appreciated as landscape trees and the wood is used for fires and cooking. Live oaks are susceptible to oak wilt, but are more resistant than other species of oak, such as red oaks.

Do brown leaves after a freeze mean a Live Oak is dead? No!

Even if its leaves brown after a freeze, the live oak will probably recover. Live oaks generally have a leaf exchange in the spring, and the leaves that were killed by frost should be replaced by new leaves when the tree starts budding. In some cases, the dead leaves may fall off before the new leaves emerge. 

If a live oak does not put out new leaves in the spring, it may have been damaged beyond recovery. Consult a local ISA Certified Arborist to evaluate your tree.

Can I do anything to help a freeze-damaged live oak recover? YES: WAIT!

With damage from freezing weather, it is often best to wait and see how the tree responds before deciding if the live oak is salvageable. In the meantime, however, taking proper care of the tree can increase its chances of making a recovery.

Live oaks that have lost their leaves cannot pull water and nutrients from the soil like they would normally, and need extra help. Once the ground has thawed after a freeze, water your live oaks by doing a root soak with a hose; don’t rely on sprinklers. Help replenish depleted soil nutrients by fertilizing and using soil amendments. Like other frost-damaged trees, live oaks will need extra care in the years to come, as the trees’ stored energy is depleted due to stress.

At Texas Tree Surgeons, we love trees and we love our community! While the effects of freezing weather will vary depending on species, live oaks should be able to bounce back from the winter weather of February 2021. In the coming months and years, as the full effects of the freeze become apparent, contact us to have one of our ISA Certified Arborists out to look at your trees and give you the information you need to best care for them!

Will My Trees Survive Freezing Temps and Winter Weather?

by Texas Tree Surgeons Extreme Weather, Resources

The effects of the historic freezing temperatures in February 2021 are widespread. After the ice thawed and the snow melted, many people were left with frost-damaged or dead landscaping. While much of the damage from the rapidly-changing temperatures is obvious, trees and plants have also suffered internal damage, and will likely show signs for years to come.

Will the freezing temperatures and winter weather kill my trees?

Unfortunately, we can already see the signs of frost-killed plants: leaves and other plant tissue that appears wet, soft, brown/black, or dried up. This type of damage is prevalent in succulents, pittosporum, loropetalum, geraniums, and related plants. Palms will likely also suffer extensive frost damage, but it is best to wait until the summer to see if they put out new growth. 

Evergreens and more frost-resistant trees and shrubs should fare better. Common examples of this group of plants are yaupon hollies, wax myrtles, and crape myrtles. These species may brown in sections, but ultimately survive. Even if they survive, some of the brown sections will never recover. It is best to wait until summer for new growth to see the extent of the damage. 

Trees with thinner bark, such as fruit trees and Japanese maples, may leaf out in the spring and appear unharmed. Damage to the inner layers of the tree, however, can prevent proper movement of water and nutrients in the tree’s vascular system and can lead to stress symptoms in the summer, appearing as a sudden browning and wilting of the leaves. 

Larger native trees such as red oak and pecan may show dieback or brown sections, but should recover if cared for properly. Live oaks may show browning, but should recover and put out new leaves in spring.

Frost Cracks

Frost cracks are caused not by surface frost, but by fluctuating temperatures, and are most-often seen on the southern sides of trees, which get more direct sunlight. On a cold but sunny day, the sun warms the exposed areas of the tree, causing expansion. When temperatures drop rapidly at night, the bark cools and shrinks faster than the tissue underneath. As the bark shrinks, it splits vertically over areas where the underlying wood is still expanded. Splitting and cracking is most common in areas where there are wounds or other damage that has weakened the bark. Young trees and trees with thin bark are especially susceptible. Frost cracks are rarely fatal and will heal over time, but can be entryways for disease and insects. Stressed trees exhibiting cracks should be given special attention and should be properly fertilized and cared-for to help protect against diseases and insect activity.

CAN I DO ANYTHING TO HELP MY TREES RECOVER FROM THE FREEZING WEATHER?

 For freeze-damaged plants, it is important to provide proper care in the short and long term. 

 WHAT YOU SHOULD DO NOW: WAIT!

  • Watch for signs of damage.
    • Browning and widespread leaf drop will be common.
    • Wait until spring or summer before deciding if a plant is salvageable.
  • Water correctly.
    • Once the ground has thawed out, and temperatures are consistently above freezing, do a deep soak watering for the roots of trees.
      • Use a hose, not sprinklers.
    • Watering can help a tree with damaged leaves to take up nutrients. 

WHAT YOU SHOULD DO IN THE SPRING

  • Have frost-damaged trees evaluated by an local ISA Certified Arborist.
    • Every tree species will react differently to the freeze.
    • Factors like location, soil conditions, and even the movement of the storm front will affect the trees’ ability to survive.

WHAT YOU SHOULD DO OVER THE NEXT FIVE TO SEVEN YEARS

  • Fertilization and proper watering will be key to freeze-damaged trees.
    • Nutrient-rich soil with beneficial bacteria and fungi can speed a tree’s recovery.
  • Do not use herbicides around affected plants.
    • Never use a “weed and feed” product near your trees.
  • Continue proper maintenance trimming and care.
    • Remove dead wood and loose bark, thin for light and air.

At Texas Tree Surgeons, we love trees and we love our community! The freezing weather in February 2021 caused damage not just to North Texas’s infrastructure, leaving many without power, water, and shelter, but also to our urban forest. Once the needs of our residents have been met, it’s a good time to think about how best to care for our frost-damaged trees and shrubs. We are here to help you evaluate the damage to your landscaping and make an informed decision about how to proceed. If your trees and shrubs don’t leaf out in the spring, or you have any other questions, let us know! We have a team of ISA Certified Arborists ready to help in any way we can!