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Raised beds around trees?

Posted by suekend 6 (My Page) on
Sat, Jun 21, 08 at 23:20

What are you thoughts about making raised beds around large established trees? My property is woods, and the ground is all rock. You can't dig at all with a shovel, and to make any kind of hole you need to use a pick, so really the only way to have a garden is to raise it up. I would like to make more gardens around some trees, but am now wondering if I will be harming the trees in any way. The last garden I made around a large tree, I surrounded the trunk with rocks to keep most of the dirt away from the trunk. What do you think?
Sue K.

Follow-Up Postings:

RE: Raised beds around trees?

The idea of a raised bed is great but one can kill a tree with to much soil on top of the ground that can keep a tree from breathing.

Try this and come back. This will apply to any soil, rocky or otherwise.

Here is a link that might be useful: planting on top of the soil

RE: Raised beds around trees?

My thought is that it is a BAD idea. The thinking about planting trees is that we commonly plant TOO deep. NOW, experts say that the root ball should be up to 1/3 above ground!

But creating a raised bed, you are in effect burying the tree deeper and depriving those all-important surface-level roots the important oxygen they need.

Also, by adding a raised bed, you're going to be putting some of the trunk in contact with soil. This can create a potential for ROT! Even if you do put the rocks against the tree, moisture will collect between the rocks and the trunk.

Sorry. My opinion is that it's a bad idea.

RE: Raised beds around trees?

  • Posted by hey_j 6 Dayton Oh. (My Page) on
    Sat, Jun 21, 08 at 23:34

My understanding is to add no more than 4" of soil around a tree, in order not to smother it's roots. That is what I did
around an established Ash tree about 15 years ago, and by adding mulched leaves every year, it is a good spot for planting!

I plant many of my hosta in whiskey barrels and pots in such beds though, to avoid root competition! But fern, pulmonaria and epimediums etc.
do really well there!

RE: Raised beds around trees?

Not taking to task Janice or melissa but they are talking about problems, I talking about how to do it without harming the trees which is very similar to what Janice says. And I don't think anything I say will conflict with her.

Don't worry about your rocky soil.

See this about where I planted on top of a limestone driveway.

Here is a link that might be useful: Driveway hosta

RE: Raised beds around trees?

Thanks for everyone's advice. Maybe combining the idea of the driveway hosta, along with adding a few inches of soil will do the trick. Now, about the driveway hosta, did you just sort of fan out the roots and lay them on the limestone, then cover with mulch? And will that be enough for the larger hosta? Because you seriously can't even dig down even 1 inch into this rocky ground.

RE: Raised beds around trees?

quite a conversation.. lacking only one fact ...


its useless around a maple.. it will grow roots into the soil .. defeating the purpose... probably before you throw the last shovel full on ...

ID the tree .... and we can go from there..


RE: Raised beds around trees?

As others said, be verrrry careful adding soil over tree roots - I managed to murder a gorgeous, huge japanese maple that offered shade & beauty outside my bedroom doors - arrrrgggghhhh....

RE: Raised beds around trees?

What kind of tree?
The last bed I made was around a very large oak, and a dogwood. That is mostly what is on our property.
Several years ago, I made a small temporary bed for hostas that is at least 5' away from any tree trunks (no maples, all oaks and dogwoods), and now as I'm finally digging out some of them to relocate them, I'm finding lots of small roots growing in there.

RE: Raised beds around trees?

"Now, about the driveway hosta, did you just sort of fan out the roots and lay them on the limestone, then cover with mulch?"

I sat plants I had purchased in 1 gal containers on top of the limestone. Later when I had not planted them in a timely manner I heeled them in (old nursery term), or put mulch around them as you might see in a nursery. I didn't get to them until the next spring and they started to grow and looked all right so I left them where they were and re-mulched. That is 8-10 years ago, you can see they are doing fine. Then I did the same thing between the house and garage on top of pure red scraped clean clay and you can't jump over those plants now.

The end, make small beds by setting the plants on top of the soil and mulch, then see that the mulch stays slightly above the crown and water because this fresh mulch will not hold water well the 1st or 2nd year.

No more complicated than that, the point is small beds separated then make more small beds next year one at a time until you are finished with what you want. The mulch will allow a lot of air and you aren't covering a large area with each bed.

BTW, I've done as I advise many times with no ill effect.

RE: Raised beds around trees?

I don't know about oaks or dogwood but I've raised the soil level around a very tall fir by 1 1/2 to 2 feet. This was 20 years ago. You can see by the picture it did the tree no harm at all. The first soil that went in was sold to us as topsoil. It actually was silt. Horrible stuff. I planted bulbs and they all rotted. Over the years I've dug the silt out where ever I'm planting and now it is as seen in the picture. The tree is happy. I asked him.

I also have planted though not as deeply on top of and right up to a walnut. That one I have to watch because over time the roots go up and I need to raise the level of the plants on top and chop some surface roots away at the same time.

This year I planted out into our woods for the first time. This was following EO's suggestion of leaving the hard ground alone and building on top of it. I'm posting some pictures on the Gallery as Wood's Project.

Hope this helps a bit. McT


RE: Raised beds around trees?

Thanks McT, that helps alot. Your garden is just gorgeous! I could sit out there all day. You gave me hope that I didn't just kill my oak and dogwood tree by making a raised bed around them.
I didn't go real far our from the trunk, so I know I didn't bury all the roots. I also think I will dig the dirt and rock away from the tree trunks, and maybe put some metal flashing around and few inches away from the trunk, giving it some air so the dirt and water won't rot it away.
Thanks everyone for all you information you've given me. My next bedding will be done differently, using all the advice I've been given.

RE: Raised beds around trees?

"maybe put some metal flashing around and few inches away from the trunk"


RE: Raised beds around trees?

Ok, my thinking was to use the flashing to hold back the dirt a few inches away from the tree trunks to prevent the possibility of rotting the tree. I guess that's not a good idea? I'm talking about the bedding that I already made.

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