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Spring Flooding and Tree Health: What You Should Know

Apr 20, 2021

How Flooding Can Damage Your Trees During Spring

Spring is an exciting time for gardeners and arborists. The brutal weather conditions from winter have come to an end, and more rain and sunshine allow plants and trees to thrive.

Unfortunately, springtime can also create some problems. Though trees need water to grow, sudden rainfall and flooding can severely damage trees. Additionally, many growers spend too much time manually watering their trees.

Read below to learn more about the risks of overwatering trees in the spring, and what you can do to protect them.

READ MORE: Common Signs of Illness in Trees

Risks of Flooding or Overwatering

Trees need water to survive. It allows them to create oxygen and spread nutrients throughout the tree. That’s why most tree owners perform manual watering – especially in dry climates or during seasons without rainfall.

However, storms, floods, and miscalculations can leave trees with too much water. This is harmful to their health, and proper precautions must be taken to protect these trees.

Read below to learn why avoiding can kill a tree by overwatering is important.

Overwhelming Roots

Tree roots have an important job. They take in carbon dioxide, trading it for healthy oxygen which is released back into the environment. Roots also transport oxygen, water, and minerals throughout the tree.

The soil must be maintained properly to keep the roots healthy and functional. Too much water can compromise soil. Specifically, soil has pockets of air that allow the roots to ‘breathe.’ When soil is burdened with too much water, the pockets fill up and the roots can’t breathe. This stops them from transporting nutrients throughout the tree, and in many cases, the tree dies as a result.

Canopy Damage

The canopy is the part of the tree that covers the ground when viewed from above. In many instances, this is the large, round shape formed by bushy leaves at the top of the tree.

The canopy’s job is to catch rainfall and slowly disperse it to the soil below. However, too much water can knock down these leaves and overpower the soil beneath them. In other words, how does flooding affect trees and rainfall can overpower the canopy, damaging both the canopy and the ground it protects.

Pest Infestation

Not only do floods bring physical damage, but you can end up with pests, fungi, bacteria, and related diseases. When flooded, trees become a breeding ground for these pests.


Spring is a huge time for tree diseases, and flooding only makes them worse. Many of these diseases are caused by fungi or bacteria. Some of the most common springtime diseases you’ll need to watch out for include:

  • Anthracnose

  • Apple Scab

  • Black Knot

  • Brittle Cinder

  • Cankers

  • Gall

  • Leaf Spot

  • Powdery Mildew

How to Tell if a Tree is Getting Too Much Water

The hazards listed above are threatening, but you can take action to protect your trees. One thing you should be doing during spring is routinely checking your trees to see if they have any signs of water damage. Taking action as early as possible is the best thing you can do to save your trees’ lives, and you won’t know to take action unless you know what to look for.

Here are four key indicators of water damage.

Damaged Leaves

Leaves aren’t just for decoration – they actually act as an indicator of your tree’s health.

Overwatered leaves won’t necessarily change in colour. It’s possible that gorgeous green leaves are actually unhealthy. The real indicator is in how the leaves feel. If you think your tree is overwatered, try touching the leaves. If they feel brittle and break apart easily, the tree has likely received too much water.

New leaves are a particularly good indicator. If a new leaf is receiving too much water, it will likely appear yellow or light green in colour.

These leaf problems usually indicate that the soil has received too much water.

Soggy Soil

When you water your soil, it’s easy to go overboard. In fact, manual watering mistakes are often what lead to poor tree health. Fortunately, it’s easy to check your soil to determine whether or not it is being overwatered. You don’t need to water your soil if the top layer feels damp. Even when the top layer feels dry, it’s possible that the soil is still damp underneath, so you should dig up a few inches of soil to check.

Algae or Moss

Have you started to notice small green shrub-like patches on the trunk of your tree? You’ve got algae – and it’s a sign that your tree is getting too much water.

Physical Flood Damage

This point might be obvious, but if a flood is so severe that it knocks your tree’s branches off, there’s good reason to believe that your tree’s internal health is also damaged.

What to Do If a Tree is Overwatered

Don’t worry – overwatering won’t instantly kill your tree. If you notice any of the signs listed above, simply water your tree less frequently. You might want to take a break from manual watering for about a week.

You may also consider switching the type of soil you use to better serve your trees’ conditions.

If you find that overwatering is a consistent problem, we recommend speaking to a professional arborist or tree care professional about what to do.

READ MORE: Prepare For Tree Removal

At Green Thumb, our team of experienced professionals can help you maintain your trees’ health, whether they face floods, pests, or other types of spring damage. Contact us at Green Thumb today.

We take pride in offering our professional Tree Care services in Ottawa. Feel free to reach out to Green Thumb Tree Specialist for end of season snow removal or any of the following Tree Services: