At the risk of offending someone...
I do not think this is a very good display. At the highest level, it doesn't tell me anything. There is no story/theme. There is no visual flow.
(1) There is no background, so the foreground elements have to stand completely on their own. I do not get a unifying theme from them.
(2) The three foreground elements make up an equilateral triangle - boring and lacking design.
(3) There is no depth to the display (may just be due to photo)
(4) There is no vertical interest - the two smaller elements are both sitting on the ground/low slabs.
(5) The elm is too large relative to the juniper.
(6) The accent "plant" does not work well with the juniper from this photo. What is it? What job is it supposed to be doing? It looks like a potato
I could go on, but I don't like this display. If these were my trees, I would display the juniper and the accent plant only... though I would replace the accent plant with something else.
Al please don't tell me this was your display, in which case you probably hate me