Some of the upright hollies such as 'Oakleaf' will give you dense evergreen screening, and won't get so darned wide, which will allow you more room in your bed for other plants. If when you say 'tree-shaped', you mean spreading up top - that will be a detriment to growing things underneath as they will cast a lot of shade onto your perennial bed -- unless you like growing shade-loving perennials like ferns, hosta, etc., it seems to me. You may also consider Photinia, Carolina Cherrylaurel 'Bright n Tight', Japanese ligustrum, Chinese evergreen oak, Holly osmanthus, Camellia sasanqua, Chindo viburnum, Leatherleaf viburnum, lots to choose from.

Bboy, it is my understanding that the harm from amending backfill comes from the restricted lateral movement of roots through the amended soil/unamended soil interface, which causes lateral roots to encircle the trunk of the tree. Downward moving roots don't encircle trunks. If the bottom of the root ball sits at grade when planted, over unamended soil, whether the backfill in the mound the tree is planted in is amended or not, there is no lateral movement of the roots possible, and thus, no possibility of encircling roots. The roots can only go straight down with this planting method, into the unamended soil underneath, and THEN laterally into the unamended, surrounding soil. The roots never have to penetrate through an inhibiting, lateral interface. The roots in the amended mound have no place to go but down in order to find water. The mound gets dry fairly quickly compared to the surroundingsoil. So the roots are trying to escape the mound, they can only go down, and by the time the roots start spreading laterally, they are no longer surrounding the trunk, they are well under the tree and out of harm's way. I believe this is a way to establish roots quicker, and not violate the amended hole paradigm, with no possibility of harm now or later. I base that on logic, experimentation, and having observed how much better trees seem to grow in clay when they are planted very high.. My theory is that the roots are forced to exit the immediate planting area surrounding the trunk faster when planted in a mound, and in addition, the tree can be watered much more heavily, without risk of drowning, Maybe I should have saved this for a more theoretical thread and not in response to a newcomer's question. M This post was edited by Mackel-in-DFW on Sat, Apr 26, 14 at 12:39

I've noticed that mature,very large trees tend to overwhelm a normal sized home in the front yard. It tends to get the reaction of "Look a huge tree! There's a tiny house hidden behind it!" Some people like the look but I like trees more to scale that don't block doors or windows off to the side a bit. Also, large trees create deep shade so you'll be limited on colorful flowers by the front door as well. I took out what would be a huge oak in my front and put in a smaller (40') Caddo Maple instead. I planted 3 huge trees on the west side in my backyard. I noticed that large trees in the back yard frame the front of the house with a lovely green. If it's a very hot west front yard I'd go with a medium dense foliage tree (50') for the shade. Good luck with whatever you choose :) PJ

I am sorry that no-one has come up with any ideas for you yet. I think the problem is partly the wetness. My first thought for your area was a Japanese maple. There are so many lovely ones in various heights, also grafted ones, weeping ones, red varieties etc. I know they will grow in clay, but I think a young one will really not like to have wet feet. You could build a raised bed to give the tree better drainage. I have seen this done very successfully. I do agree with NOT planting a mop-top (by which I assume you mean a Robinia). You will have problems with suckering. I think planting a group of Silver Birches may slow them a little, but they will still get big. I'm sorry I can't be of more help. Cheers, Dee.