One thing that I have learned in gardening is to balance the plants with a few hard scape elements. It adds such a nice definition and contrast to the yard. Now, garden snob that I am, I am definitely not talking about plastic lawn ornaments and flamingos. I have a few nurseries in the area that always seem to have just the right treasure for me to tuck in among the flowers. I have lots of bunny statues and bird houses scattered around.
I love my Celtic Cross. Be sure to use white in the garden as it shows up so nicely in the evening.
You can use old found objects like this rusty tricycle tucked into a corner.
An iron filigree planter placed in another planter adds character and height.