Freeze And Frost Tree Recovery

Trees:

Established native trees do not usually die from extreme cold. Many of our native trees also grow much farther north and are perfectly fine with temperatures below 10 degrees F. There are some exceptions. Thin barked trees are much more likely to experience irreversible frost damage. Redbuds and Viburnums are among the full-sized native trees that may suffer. Other native trees less than an inch in diameter can also freeze to death because the bark is not thick enough yet and they typically would be protected to some degree by the mother tree towering over them. In a landscape setting this often means that they are exposed in a way that is harmful. Among the non-natives that are commonly damaged from frost are Queen Palms, Sago Palms, Bottlebrush, and Ponytail palms. Florida Sabal Palms are hardy to 15 degrees while the native Texas Sabal is slightly colder hardy at 10 degrees. The freeze of 2021 reached lower than 6 degrees in some areas around Houston and we at ArborTrue have already begun to see trunk damage on Sabals.

What to do? Look for cracks in the bark. This means that the water in the trunk froze, expanded, and ripped the bark open. This symptom may not be visible right away and may not show up for a month or two. Do not trim the tree yet! For Palms, look for wet spots on the trunk, this symptom will show up almost immediately because the cells died and are leaking their moisture directly out of the trunk. This does not mean the whole palm is dead, it means that parts of the trunk died. The tree will need immediate attention (within 2 weeks ideally) to survive. A qualified arborist can scrape out the dead tissue and seal the wounds to prevent future fungal infections. If the bud of the palm is brown and the fronds are drooping most people cut down the palm before it has a chance to recover. Collapsed fronds almost always mean death in warm weather but after a cold snap it does not! Without a surgical procedure, the palm will probably die but there is a way to revive them. The exterior of the bud in this case has been killed and the tissue shrinks tightly against the interior living tissue. This creates a shrink wrap type environment that prevents the new frond spikes from growing out of the top. By carefully cutting open the very top of the bud, and sometimes down the side of the bud, the pressure is relieved and the new spike and start to grow out. When we do this later in the season, around April or May, the spike starts shooting out of the top instantly. In a matter of minutes, the spike may be protruding from the top by a few inches. On palms with more extensive damage, sometimes we can cut down the side of the bud very carefully, and manually pull the frond out of the bud to expose it to sunlight. Once sunlight hits the frond the tree begins to revive. The palm may still have some rotten spots develop on the trunk later on, those need to be addressed to prevent Ganoderma trunk rot. All frost damaged trees will benefit from a professional fertilization by a qualified arborist.

Turf:

Perennial turf grasses like St. Augustine, Bermuda, and Zoysia will recover from the frost even if you lost a little of it. Its immensely important to avoid synthetic fertilizers, especially in a stress situation. Fast release and synthetic fertilizers on frost damaged turf can easily cause a pathogenic fungal attack. Slow-release organic fertilizers are best for this situation and frankly, its all we recommend. It is extremely difficult to use synthetics without causing harm to the soil and therefore the plant. ArborTrue uses a special blend of minerals and organic nutrient sources for frost recovery on turfgrasses. The treatment is only needed once in most situations and then you may return to your normal organic routine. Winterized lawns recover from frost quicker than non-winterized lawns. Organic lawns often times done even freeze because the high microbe content warms the soil. Winterization is the practice of applying extra potassium before the turf goes dormant. Potassium helps move nutrients currently in the leaf down to the roots for storage. This reduces the loss of nutrients in a freeze and allows the turf to explode back to life as soon as the temperatures warm up. We can help with professional winterization of turf grass for you next time.

Shrubs:

As arborists, we work primarily with trees but because trees share the landscape with other plants, we are often asked to give advice. Its hard to look at damaged landscape and this often leads people to act before they should. There are some things you can and should do right away but there are others that should wait. For reliable natives such as Hamelia, Salvia, and Lantana, go ahead and cut them back whenever you like. Also, if any of the plants are “mushy” you can cut them to the ground. Do not pull them out yet though. Give the soil a chance to warm up over the next couple months. A common question we get is about roses. Roses have been hybridized and commercially cultivated for so long in human history that they are definitely not all created equal. Again, if the tissue is mushy, go ahead and cut it back to the green wood. For most roses, I recommend waiting to see where they leaf out, then trim the dead tips back to the leaves. This again means more waiting. Many roses will not be negatively impacted at all so be patient. Azaleas can be remarkably cold hardy. If they lost their leaves in the frost, give them time. Remember that in the Houston area we have had frost as late as mid-April. If you trim before then you risk further damaging the plants. ArborTrue can help you revive the landscape with a special blend of nutrients for frost recovery. If you cannot afford an arborist you can try spraying liquid seaweed and molasses. This is a great source of minerals and carbohydrates to revive the soil and the plants. Spray the whole plant to the point of runoff and drench the ground as well.

Remember, if its mushy, cut it down. If you are not sure, just wait and see. Either way, a lot of energy leaves the landscape during freeze events and professional help is only one step away. Call on Arbortrue for all your freeze and frost recovery whether it it is a tree, shrub, or your lawn.