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

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.

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!

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

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.

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

WHAT KIND OF TREE????

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..

ken

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....

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.

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

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.

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.

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

NO NO NO NO

esther,
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.

Walnut & Hickory trees are bad about taking the life out of a bed, as McT said.

Love the photo!

Wow. An eight year old post.

Walnuts aren't always bad. This Striptease is near the trunk of a 50 foot Black Walnut.

And this Brother Stefan is well within the dripline...

...as is this June...

...as are all of these.

No added soil, just a few inches of homemade compost every couple of years.

tj

I found this thread when I googled" raised bed around trees".

There are about 200 plants that Black walnut will kill(tomatoes), but I was talking about the fiber root system. Your compost & watering must be top knock or you have a green hand, maybe both.

Perhaps I'm blessed. The soil was gummy clay prior to adding compost starting 25 years ago and I rarely water. My point is that the fibrous root system walnuts are touted to have may not be that bad in all circumstances. And BTW, these are just some of the hosta under the dripline. There also are many other trees, shrubs and perennials under Black Walnuts as well. Neighbors to the north and south of me have/had very large Black Walnuts whose canopies nearly touched. One was removed last fall. Over the decades I've come to learn the facts, myths and inconsistencies of walnut lore as it pertains to both above and below the soil.

tj

Clay and hosta seem to go together very well. I know another guy who had the most amazing hosta garden on clay in the Bavarian Alps. And if you see hosta from pictures in nature in Japan, that seems to be rock and a little moss that they are clinging to and do so well. I will try myself next spring. Our town management built some new beds beside the streets and filled it up with clay where nothing seems to grow, so I will put some spare hosta on top of the bed directly in front of our house and cover it with mulch. Seems to be a good idea :-)

TJ, beautiful, beautiful hostas in those wonderful photos. I found your comments very informative and was wondering if I could use the floor/ground under the dogwood that houses my potted hostas. I discovered its network of fibrous roots when I was planting near the edge of the beds adjacent to it where my potted hostas grows few years ago. I am so afraid of killing that tree by adding soil to create a bed. It was a strappy little thing when I transplanted it from my daughter's garden years ago that has grown into a lovely tree that provides dappled shade to my potted hostas.

I put a raised bed under a 50 year old pine tree and it looks really nice and doesn't affect the roots because the tree is so big and the roots go out really far beyond the raised bed. The problem is no hostas will survive there. The tree is like an umbrella so it gets little water when it rains and no snow cover in the winter.