Fall in Texas often means storms and heavy rains that saturate the ground. While trees in the region are accustomed to this amount of rain, too much water threatens trees’ ability to stand tall, strong and steady.
Just like most living things, your plants, shrubs and trees can only handle so much water. When torrential downpours create puddles of standing water near the bases of tree trunks, problems may occur above and below ground.
“After approximately seven days, standing water can seriously prevent oxygen from reaching tree roots underground, which may contribute to root rot,” explains Matt Petty, a certified arborist and assistant district manager at Davey Tree. “And if the foliage retains water over time, the excess moisture can breed foliar diseases.”
Anthracnose is a huge problem right now. It effects oaks, dogwoods, maples and plane trees. Rust problems are also a concern, as this disease will contribute to early leaf drop.
Regardless of a tree’s health, flood-prone areas are particularly threatening to root systems. Similar to the way animals and humans suffocate due to lack of oxygen, after about seven days root cells will die if they become saturated with water for an extended period of time. Excessive water deposits also wash away soil from the root zone, which weakens the tree’s stability.
Flooding can also cause floating debris to damage trees and their bark and postpone tree care and maintenance. For example, proper tree-trimming and fertilization applications are not possible with heavy amounts of rain collecting near trees.
Petty suggests monitoring low-lying areas at the base of tree trunks to prevent rain from collecting in puddles. “Aerate low areas and incorporate compost and soil before the rain falls. This will ensure your landscape is equipped with proper drainage capabilities,” he says. Pruning the canopy will help increase air movement and deter disease pathogens from festering there, and it will improve trees’ ability to withstand excessive rain. Submerged foliage may not recover if not addressed in a timely manner.
Trees may express several different warning signs as a result of flood damage, including structural damage, premature fall color, wilted leaves, discolored foliage, die-back, pest infestations, exposed roots and/or an unstable trunk. Although flooding can take a toll on trees, removal isn’t always the best or necessary option.
To help ensure your trees stay strong and healthy after a storm, you can manage flood damage before it gets out of hand. Address concerns ahead of time by:
- Pruning dead or broken branches
- Re-setting or staking trees that are unstable or leaning
- Managing pests as needed
- Adding mulch to protect new sensitive roots and improve aeration
- Managing mineral nutrition with micro-nutrients and slow-release nitrogen sources
- Leaching soil where saltwater has intruded to remove sodium
- Removing sediment deposits to return soil level to original grade
Always select trees for your hardiness zone to set yourself up for success. Plant new trees and shrubs in fall or spring – not summer and winter – so their root systems have time to take hold. Here are the best trees for Houston’s climate:
- Bald cypress (zones 4-10): A sleek, pyramid-shaped conifer that loses needles in the winter, thrives in swamps and can tolerate flooding.
- Southern live oak (zones 7-10): A spreading, broad leaf evergreen tree that adapts to almost any soil type and can tolerate salt spray and can handle short duration flooding conditions.
- Southern magnolia (zones 6-10): A pyramidal evergreen tree that produces flowers and can tolerate occasional flooding, but not prolonged inundation.
Because trees take many years to reach maturity and add significant value to your property, monitoring is critical before, during and after severe weather occurs. If you experienced a wetter summer than usual, look out for your trees. After all, a tree’s impressive stature and natural beauty are among many reasons why trees deserve your care and attention.