i wouldnt do it .... no particular reason ...

take some larger rocks or paving stones.. or wall bricks.. and make a ring out from the trunk a foot or two ... and do not raise the soil near the trunk ...

in other words.. make a well ...

this of course... begs the question of whether you can bury the roots that much deeper without impact ... i doubt a couple inches would matter .... i presume others will disagree ...

ken

It is mainly a matter of air access to the roots for oxygen supply. Roots need oxygen for respiration, and the sudden dumping of a thick layer of soil cuts off oxygen diffusion to the roots, killing them faster than new roots can grow into the aerated surface layers of the new soil.

Resin

Right, guess I wasn't thinking about the roots; somehow the issue of root flare was preoccupying me... how does it form and why, and what is so sacred about it if the same tissue is initially there above and below ground?

But anyway, air for the roots; of course, I should have realized that. Thank you. So perhaps a gradual elevation of the soil level would worth a try.

As for rock wells... in my little space these would be dank spider traps impossible to get your hand into for weeding, not like life on your acreage I'm afraid, Ken. And thus might not protect most of the roots anyway. When I say rock garden, I'm talking small :-)

Thanks!

KarinL

define raised rock beds .... perhaps we dont understand ...

a pic???

are you talking about just adding some rocks ???

why are you raising it???

more facts might get you some ideas

ken

Another problem with fills over tree roots is the water supply to the roots being affected by differences in soil texture between the existing soil and the fill soil (same as with differences in texture between amended planting hole backfill and unmodified soil around the planting hole).

Fills over existing roots may or may not be devastating, depending on the nature of the fill soil used, depth applied, weather conditions, time of year, species involved, machinery used and probably other factors. However, if the trees are highly valued, no fill should be allowed...

Never add more than two or three inches of fill soil at a time, even under the most favorable conditions. If more fill is required, do it over a year or more or remove the tree

--Whitcomb, Establishment and Maintenance of Landscape Plants (1987 (1991), Lacebark Inc., Stillwater)

Here is a link that might be useful: Lacebark Inc.

Another good point, bboy. Although they'd need less watering than if transplanted, I suppose, their roots being left intact...

Ken, I'm making raised beds because my property is dead flat and I needed some contour and elevation changes for a variety of reasons. I'm basically putting a row of boulders together, somewhat artfully I like to think, and filling the resulting enclosure with soil. I'm not sure a photo now would say much, as (a) there are still as many rocks lying around as are already set up, and (b) it is cherry blossom season and my street tree has blanketed my yard with pink petals; it looks odd to say the least. But I'll try later.

I think the bottom line is whether or not I'm willing to risk these particular plants, or perhaps more accurately, which risk I can best mitigate; the effect of covering the roots or the effect of transplanting them. The yew is not so much an issue, but the Chamae would be a shame; it's just a little obtusa nana aurea, but has at least five years of growth on and is quite pretty.

Will see if I can find a presentable section to photograph later.

KarinL