Knowledgebase

Tree planting height #890054

Asked November 19, 2024, 4:11 PM EST

I recently had a landscape company plant five, six-foot Black Spruce trees on a slope - about 45 degrees. The root ball is exposed on the one side. Should I cover the root ball with mulch, leaves, or dirt for the winter? They were planted in July and have received regular watering throughout the growing season. Photos attached. Thanks for your advice!! :-)

Kent County Michigan

Expert Response

Hello Dan,

Thank you for contacting Ask Extension. Did the landscape company plant them so that the root ball was covered, or has the soil fallen away from the root ball? Also, when they planted the trees, did they pull the burlap back? Because it looks like it is still there. 

As soon as you answer these questions, I can give you an assessment.


Thank you for contacting us! Replied November 19, 2024, 8:23 PM EST
Diane,

Thanks for responding and for your questions. No, the landscape contractor did not remove the burlap from the root ball. He said that was unnecessary and the burlap would break down over time. (I have always removed coverings from root balls but these trees were bigger than I am used to planting.) He did put some loose mulch around the trees when he planted them and some of that may have fallen away. I was thinking about reinforcing the root balls where the bottom half is exposed. I would use my wheelbarrow to move dirt/compost from another area of my yard and sort of pile it up on the downslope side of the tree. I have heard some people say you should plant a conifer tree with the root ball high (exposed top portion) in the ground. I am just a bit perplexed with this slope and I do not want the roots to get too exposed to the freezing air come winter.

Thanks for your help and expertise!

Dan

On Tue, Nov 19, 2024 at 8:23 PM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied November 21, 2024, 8:43 AM EST

Thank you for the comments and answers to my questions. I agree that you need to cover the roots before the weather gets colder. The burlap on the trees need to be cut away also. Yes the burlap will break down, but it takes several years to do so, and in the meantime, your trees will begin girdling themselves, shortening their lives. Also, the trees should have been planted more into the ground, than just into the slope.

Planting a tree on a slope is more challenging than putting one on flat ground. Here are a few tips to help ensure its success.

  • Aim for dead-center when placing your tree on the shelf. Avoid covering any part of the root ball with the hill's slope or the berm soil.
  • Only mulch two to three inches deep. If you add too little, the mulch will be ineffective while adding too much can cause rotting problems by retaining additional water.
  • Try to minimize disruption to the hillside when planting on a slope to maintain the hill's stability.

Looking at your pictures, terracing your slope might be your better option. Obvious you cannot do it now. And if you put more soil around the rootball, the soil can be washed away during the winter. The best you can do is possibly Wedge a board or rocks around and under the plant, and cover the roots as best as you can, at this time. In the spring, you might want to terrace the area below the trees, so that more soil and mulch can stay around the root system. You should wait until this time to also cut the burlap back on the exposed sides.

I have included several publications for your reference:

https://clemson.app.box.com/s/0xk86qwuo4kkm4wxmg7o10ijfui8fk5r

https://www2.dnr.state.mi.us/publications/pdfs/huntingwildlifehabitat/landowners_guide/Habitat_Mgmt/Backyard/Tree_and_Shrub_Planting.htm

https://yardandgarden.extension.iastate.edu/how-to/gardening-slopes-and-hillsides

If we can be of further help, contact us.

Thank you for contacting us! Replied November 21, 2024, 3:04 PM EST

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