Freeze and Frost Tree Recovery in Houston

Some plants are hardier than others; this we all know. With so many different plants and trees in the landscape, which ones are fine after a freeze and which ones need help? Records are occasionally broken with low temperatures, and in these times, the help of an expert Certified Arborist or Board-Certified Master Arborist is priceless. Trees, shrubs, turf, and tropicals will need different kinds of help depending on how badly frozen they were. Let our experts help your landscape recover from freeze and frost damage.

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 harmful way. 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.

Cold Hardy Palms Overview

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 require immediate attention (ideally within 2 weeks) 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 it. 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 starts 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 fronds, 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 professional fertilization by a qualified arborist.

Turf

Perennial turf grasses like St. Augustine, Bermuda, and Zoysia will recover from the frost even if you lose a little of it. It's crucial 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, it's 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 regular organic routine. Winterized lawns recover from frost more quickly than non-winterized lawns. Organic lawns are often done even in freezing temperatures 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 the 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. It's hard to look at a 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 of 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, we recommend waiting to see where they leaf out, then trimming 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 an excellent 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 it's mushy, cut it down. If you're unsure, 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 is a tree, shrub, or your lawn.