When Do Tree Roots Grow the Most?

Each spring, we eagerly await the moment our trees will sprout that first leaf–then another and another.

While it’s easy to see when trees grow new leaves, we can’t see when their tree roots are growing. Luckily, our scientists at the Davey Institute study exactly what is happening underground with trees. With their discoveries, we can understand and care for trees better.

Below, learn how much trees grow each season and how you can help your tree roots grow more.

All About Tree Root Growth Rate in Spring, Summer, Fall and Winter

When do tree roots grow the most?

In general, tree roots grow the most in late spring through very early summer. Many trees experience another smaller growth spurt in early fall.

This second period of growth is very dependent on what kind of tree you have. Some tree species experience this. Some grow a little. And some don’t undergo this uptick in fall growth.

Do tree roots grow in winter?

Yes and no! As long as the ground temperature is above freezing, tree roots can and do continue to grow. As soil temperature moves closer to 36°, roots grow less. Then, once it’s freezing, growth pauses and resumes as soil warms.

Overall, it’s safe to say your tree roots do grow a bit during winter. But, from November to April, any root growth is a bonus.

When do tree roots grow the fastest? How can I help trees grow faster?

“Right now, there isn’t enough data or research to prove definitively when tree roots grow the fastest,” said a technical advisor at Davey with over 35 years of experience. “We do know that roots grow anytime the ground isn’t frozen–if they have the water, air and nutrients they need,” he added.

Trees depend on us to provide essential nutrients, which are found in fertilizers. Once they have that, tree roots can keep on growing! Then, when the nutrients are depleted, growth slows or may even stop.

At Davey, our experts use Arbor Green PRO^® and Arbor Green Xtra plus B (depending on the region) to keep trees nourished each year. The fertilizers are designed to slowly release nutrients uniformly over time, regardless of when they're applied. Our goal is to always make sure your tree has enough nutrients to keep on growing.

Click to read more about how fertilizer can help your trees – and their roots!