What's the rational for clearing all the grass? I would plant the shrubs directly in the grass after slicing off just enough sod to make the planting hole. Then invert the sod and replace back where it came from around the shrub. You can then make newspaper or cardboard circles to go around the shrubs and cover with mulch.

If you clear all the grass you will open up bare ground for weeds to come in.

Floral, thanks for the response. I am growing several Ninebark shrubs which have an arching growth pattern and hang down where my mower will go. In the process of mowing I would damage the shrubs. So, it is so that I don't need to mow under them because I want them to grow to their natural shape. I plan to mulch the area after planting, or grow a groundcover over the top.

Mow the grass really short, plant the shrubs, then lay several layers of newspaper over the area you want to keep grass-free.

Cover with mulch, then plant your groundcover through the mulch when you have time.

Way less work for you.

Thanks lazygardens, I really want to get the shrubs in the ground before the heat of summer - I am in zone 5b so now would be the time. I never thought of planting the groundcover through the mulch as well. Just punch out some holes through the paper for the groundcover?
It just occurred to me from floral's post that maybe I don't need to dig out the area underneath the viburnum I am planting. I am planting three of the same ninebarks in a row, and then a viburnum. So, I am thinking I only need to do the ninebark area, and just a mulch ring around the viburnum? Any thoughts on that? Thanks again!

The mulch rings can be as big as you like - even extending out far enough to accommodate the ninebarks. It's just that principle of only dealing with the minimum area you need rather than clearing a big area and inviting weeds in.

Floral and Lazygardens you rock, I'm currently rectifying my mistakes thanks to you, and my little bushes that were surrounded by weeds thank you !

And so does my vertebrae ;-) !

Floral, thanks for the response, I think because I am planting 3 of the ninebarks in a row it will still take a large area for them, but I will re-assess with your suggestion in mind, less work would be very desirable. Sometimes when I plan on beautifying things in my yard I forget that I am adding more work onto myself! But when I see yards with hardly anything in them they look sad. Anyways - thanks again.

The others already have described it but here's a video that shows how you could plant the new trees/bushes without tilling the entire grassy area.

In this case, the existing tree is already there but you can extend the idea to new plantings also. You don't have to follow exactly the same steps or materials.

Here is a link that might be useful: How to Sheet Mulch Your Garden

This post was edited by gardenper on Fri, May 16, 14 at 16:22

Removing the existing grass means you will also be removing the existing "topsoil" where the most Soil Food Web activity is. As floral has described plant the shrubs and then cover the existing grass with newspaper, or cardboard, or something else impervious to light that will eventually be digested by the soil bacteria and the nutrients in that grass will then feed the soil bacteria which will then provide nutrients to what you plant there. There is no need to cut the existing grass short either, depriving what is growing there with access to sunlight will kill it and at the same time feed the Soil Food Web and at least reduce the amount of supplemental nutrients you may need to supply the new shrubs.

Thank you all who responded. The video was very helpful as well. I did do the cardboard method. This will be very interesting to see how it goes. I can see where the existing grass and soil breaking down will make great compost for the plants.