I have a dwarf cherry on the way and am planning on planting it in the front yard. I was told by someone local to not plant the tree any deeper than it already is in the pot or follow the instructions for bare root trees. I was told to strip off the sod, put the bricks together for the "planter," add my dirt, plant my tree at the appropruiate depth in the soil, and then add the flowers in the top. Of course watering the soil and tree.
So how big, in diameter should the circular "planter" be for a dwarf cherry? The tree is only supposed to get to 8-10 feet tall. Should I line the vertical wall of the "planter" with plastic or weed cloth to prevent tree roots from coming through the bricks?
Will your planter have a bottom? Or are you just lining the outside of the planting area with bricks?If the latter, then you don't have to worry over much about width...the roots will spread as they need to...that being said I would allow at least 6 feet across for your planting area.
What I would do is, make the planting circle / square or whatever shape you want in the garden by removing any vegetation, dig the soil and add some compost / manure etc to feed and improve the soil texture etc, then replant the small tree into a larger pot of good quality compost mix, then place the pot / tree into the new dug hole, this way you can manage the tree as each year you re pot it into a larger pot,till it is able to be planted without the pot as it has grown big enough to support it's self, this allows the root system to be restricted slightly and allows the tree to make good roots instead of trying to make too many to fill a huge hole at the cost of blossom or top growth.
IF this sound like a lot of work then plant the tree without the pot into the planting hole, and add the other plants, just don't plant too close to the root system of the tree as this is competition for moisture etc. when I plant any tree / shrub, I cut the bottom off a plastic drinks bottle, place this Top (neck end ) down into the soil at the roots, then back fill leaving the 2 inches of the bottle out of the soil, then when you water the tree you fill Up the bottle a couple of times so you know water / feed is going down to the roots where it is needed, after couple of years you remove the bottle and the tree should be self supporting, what causes more new young trees to die, is lack of water down at the roots, after watering if you scrape away some soil, you will find the soil is bone dry.
Good luck. WeeNel.