Clemson University students are learning from the best about how to correctly plant a tree and watch it grow.
And a Clemson horticulturist has some expert advice to help homeowners plant their own trees.
Students in Ellen Vincent’s Horticulture 1010 class are increasing their knowledge by working with arborists in the Clemson Landscape Services Department to learn more about trees. Clemson University recently was named a Tree Campus USA School by the Arbor Day Foundation for the sixth consecutive year, an honor Vincent said speaks highly of the university’s arborists.
“We have exceptional arborists working in our Landscape Services division,” said Vincent, a Clemson University environmental landscape specialist. “It is a great honor for us to have our hard-working landscape services arborists teach our students. The Tree Campus USA award demonstrates their commitment to educating people about proper tree care and tree appreciation.”
Paul Minerva, a Clemson Landscape Services arborist, believes experiential learning is an important part of students’ college experiences.
“We do this six to eight times a year,” Minerva said. “We enjoy sharing our skillsets with students whenever possible. We believe it’s important for students to see real-life arboricultural tasks firsthand.”
One of the tasks students learn is how to correctly plant a tree. Vincent said this is important because many people don’t follow proper procedures when planting trees.
“Nationwide, trees are being planted too deeply and improperly,” Vincent said. “By working with arborists in Landscape Services, the students learn how to properly plant trees.”
The students also learned how to use a resistograph tool to test trees for wood rot or decay. A resistograph detects decay and cavities in trees and timber by using a small drill bit to get an accurate reading of any wood timber. The wood’s resistance to the drill is recorded on a strip of paper much like an electrocardiogram reading. The tiny drill holes close up without damaging the tree.
The students said working with the professionals is an excellent supplement to classroom learning.
“Activities such as this improve learning because we get to see what can happen,” said Adam Parkins, a junior horticulture major from Union. “We get to see what can go wrong and what can go right based on what we do. We can discuss things on a moment by moment basis and determine what is important for certain tasks and what is superfluous. Before this activity, I had no idea how trees were planted and I only had a vague idea of how they were cared for.”
Jacob Cathcart, a freshman agricultural education major from Irmo, agreed.
“Hands-on activities such as this support learning by reinforcing concepts learned in class,” Cathcart said. “Activities such as this allow students to experience what they are learning, as well as give them the ability to remember activities related to what they are learning.”
In addition to hands-on learning, the tree planting exercise also was held as a pre-Arbor Day event. Arbor Day is celebrated in South Carolina this Friday, Dec. 2, and Bob Polomski, a Clemson horticulture expert, has some advice to help homeowners correctly plant trees. Polomski said container-grown plants and balled and burlapped plants with well-developed root systems can be planted throughout the year, but it is best to plant them in the fall.
“Fall planting allows the carbohydrates produced during the previous growing season to be directed to root growth since there is little demand from the top,” Polomski said. “This additional root growth may lessen the dependency of the plant on supplemental irrigation the following summer.”
Planting trees at the correct depth is also important. Trees that are planted at the correct depth and receive the proper amount of water are better able to establish themselves and flourish, he said. Some pointers Polomski gives for ensuring trees are planted at the proper depth in well-drained soil are:
- The planting hole should never be dug any deeper than the height of the root ball. This means that the soil at the bottom of the hole is left undisturbed. Setting the root ball on loosened soil will cause the tree to settle and sink too deeply into the soil.
- Locate the topmost layers of roots in the root ball so that it will be level with the soil surface.
- Check to be sure that there is not an excess layer of soil (or container media) already covering the root ball. As little as a half-inch of excess soil over the root ball can inhibit or prevent water from entering the root ball, especially on trees planted from containers. Only mulch should be placed over the root ball.
- The planting hole should be at least twice and preferably five times wider than the root ball. Roots will grow more quickly into loosened soil, thus speeding up the tree’s establishment time.
For poorly drained or compacted soil, Polomski advises homeowners to:
- Place plants higher than the original planting depth at about 2 to 4 inches higher than the surrounding soil.
- Build up the soil beside the root ball so that the sides are not exposed and do not place additional soil on top of the root ball. This will allow oxygen to reach the roots in the upper surface of soil. It will also cause excess water to drain away from the plant rather than collecting beneath it.
- Do not disturb the soil under the root ball to prevent any later settling, which will move the plant roots deeper into the soil. The top of the root ball may dry out quickly in the summer on some sites, so be prepared to irrigate accordingly.
In addition to planting trees at a proper depth, homeowners also need to know about soil preparation, soil tests, organic amendemnts, filling the planting hole and other tasks related to planting trees. For more information, see the Clemson Cooperative Extension Service Home and Garden Information Center Planting Trees Correctly fact sheet.
(Written by Denise Attaway, Clemson University College of Agriculture, Forestry and Life Sciences; Public Service and Agriculture.)