I assume major goal is to avoid killing a 26 yr old tree...in that light, don't dig much into the root zone...and don't build the soil up and suffocate the root by denying them oxygen exchange.

Given that I had an established flowerbed under a very large river birch in Oklahoma for twelve years, it's quite possible. The birch does steal a fair amount of water from the bed, but not as much as a shallow rooted maple would.

(opinion) Landscape fabric is evil...never touch the stuff...just use newspaper and other organics to choke out the grass, though I'm afraid (depending on your lawn grass, which you didn't tell us), one cold season isn't enough to kill the lawn out.

Yes, dbarron, major goal is not to kill the birch. I have no idea what type of grass we have. We did this process 3 years ago under a oak, grass was dead in spring. Fabric will be removed in spring, just there to keep area clean until I can plant. Do not plan on adding more than 3 inches of compost to avoid suffocating the roots and do plan on watering more to support tree and new plants.
Thanks!

first.. i would have the tree inspected.. to determine if the part leaning towards the house.. has any potential to fall on the house ... birch is not the strongest of wood trees for hanging over houses ...

i dont have any idea.. why you would pic up leaves to mow.. why not mow them??? .. but i digress ...

do not substantially add soil on top of tree roots ... and adding good soil.. will only make the tree grow feeder roots into good soil ...

if you are interested in hosta.. ask the same ??? in the hosta forum ... i am not sure birch is a hosta friendly tree ... seems to me.. mine are very surface rooted ...

frankly ... i would just round up the grass.. add mulch to a settled height of 3 inches.. and plant in spring ...

i would dig hole.. insert bare root plant.. and fill with the soil removed..

i would broadcast all water.. and fert ..

i learned to NEVER water just the plants.. or that is were the tree will grow new feeder roots.. since you cut all the roots to dig the hole ...

see you in the hosta forum ...

ken

Things which will grow under birch (i.e. dryish shade) ferns, hardy cyclamen, hellebores, ferns, bleeding hearts, Japanese anemones.

Ken, not picking up leaves, my yard is a leaf haven, raking...what is that! Picking up branches that the tree decides to shed every week, worse we have had a lot of big wind storms this summer. I think you are right about not adding any kind of soil, just roundup and mulch and plant in spring, water and fert the entire area. My first concern was not killing the tree, despite the mess it causes I really like it. I will post this ? in the hosta forum.

Floral, I see so many pictures of birches with hostas planted under them. (I have been researching this project for over a month now, spreadsheets...pictures...plot drawings... I am now dreaming about hostas). I guess I would be disappointed not to be able to plant hostas.

Thanks!!

drc215 - I would love to plant hostas if they survived the gastropod onslaught in my garden. This is how they end up. (And this one is planted in a three foot tall container).

Floral, nasty creatures! I don't have a problem with them...yet (knocking on wood). I do have moles, voles and gophers! Maybe the moles are eating the slugs...I could let them stay if that is the case. But the voles and those cute chipmunks have to go!

I have no doubt your plan will work. And as far as the kill-off of the existing turf-most likely a mixture of Kentucky bluegrass/fescues here in the north-I like the suffocation method just as well as glyphosate, although I'd rather see this thirsty tree being able to get all the moisture that falls on its rootzone area between now and shade garden time. Plus, having sprayed a ton and a half of Roundup and/or its many offspring, I'd probably just do that, following with a light top-dressing of compost, then actual mulch. You should be good to go.

+oM

Thanks +oM - appreciate your input!