Where do the tree roots go above a retaining wall?

14 years ago

We have a tanyosho Japanese red pine planted a few feet from a 1' high retaining wall. We also have a couple of Japanese maples--an Emperor I that is 3' from a 2' high rock wall, and a Waterfall that is 18" from a 1' high rock wall that is above another terraced retaining wall.

As these trees become larger, where will their roots go? To the edge of the rock wall and dry out? Or will they go down to the level below the rock wall seeking water before they get to the edge of the wall?

Anne

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Comments (2)

ken_adrian Adrian MI cold Z5
14 years ago
last modified: 9 years ago
the roots will go.. wherever it is advantageous for the plant ... i doubt we can speculate beyond that ...

how is your wall secured to mother earth .... there is a chance large roots will push out an unsecure wall ...

and which direction does the face of the wall face ...

i dont understand why you think the wall will cause the roots to dry and die ....

more facts please ...

many maple.. and pine.. are happy to have their roots on the surface ... so a little drying atmosphere is not really going to stop them ...

your bigger problem might be the pine.. check the link ... UNLESS you have some named dwarf or mini pine... the potential for a plain old red pine is spectacular .... it wont be long.. before you wont ever see the wall again...

ken

Here is a link that might be useful: link
jimandanne_mi
Original Author
14 years ago
last modified: 9 years ago
Ken, thank you very much for your comments! Here is some more info; if you can add to what you've already written, I'd appreciate it.

The walls are made of 12-18" natural rocks dug into the ground just a little, with no foundation since the walls aren't very high. We hadn't thought about eventual large roots moving the rocks in the walls (we've been more concerned about the gophers destroying them!), but I'm sure you're right about this.

The Tanyosho is behind a long wall that faces the house (west, but there are lots of oak trees that block the afternoon sun from the wall) and meanders across the front of our lot about 20-30 feet from the street. The land slopes gradually down from the street and then back up in front of the house. This wall was put in to hold about a foot of top soil that was added to the slope so I could plant shrub and floribunda roses out front to get the morning sun. If the roots push out the wall, that would still be ok since there is plenty of space below this wall, and if it becomes a rock garden instead of a continuous wall, that could also look very pretty. The wall doesn't have to be there to hold the soil (I didn't want to spend the money), but my husband just thought it would look nicer with a wall, and it does.

We know about how large the Tanyosho gets in about 25 years since we saw a couple out at Hidden Lake Gardens where my husband fell in love with the exfoliating bark. They look just like the second one on the left side of the pictures in the link you have in your post (BTW, I love the bonsai!). Since we went out there after having you recommend HL Gardens here, you probably know which trees I'm referring to!

The Emperor I and Waterfall are behind a southeast facing wall in front of the house that gets filtered shade for most of the morning. In the summer, they get the most sun early to mid-afternoon. There's room below this wall for more rocks and soil to be added and to have a rock garden if the wall gets moved and destabilized by roots. This is probably what we'd have to do, since the wall is very necessary since it is holding up a lot of fill that has the paver walk above it going from the driveway/garage area to the front porch.

The Emperor I was just planted last summer. I had to water it and the Waterfall (planted with the Tanyosho 2 summers ago) constantly to keep their leaves from shriveling up. Our soil is loamy sand with a few inches of top soil added on top. We don't have anyplace else we could transplant them to since there's not enough sun elsewhere on the lot, so I was just trying to figure out if they all are likely to survive over the long run.

I also remembered how clearly defined the root layer was when they dug for the foundation of the house--everything below about 6" was sand, with no roots or other organic matter. So I was trying to envision where the roots of these 3 trees would grow--down for a foot or two to get to the next layer of soil at the base of the walls where there would be moisture? I didn't know if they could live under these circumstances. I'm not as worried about the Tanyosho, since we were told to water it sparingly, if at all.

Anne
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Where do the tree roots go above a retaining wall?

Comments (2)

ken_adrian Adrian MI cold Z5

jimandanne_mi
Original Author

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Where do the tree roots go above a retaining wall?

Comments (2)

ken_adrian Adrian MI cold Z5

jimandanne_miOriginal Author

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jimandanne_mi
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