Night Has Cast Its Shadow...

I believe this photo would be considered as a 'good composition' photo for the following reasons: 

A). There is variety in the lines, shapes, and sizes presented in the composition. In terms of lines, we have several presented. For example: there are the horizontal lines of the siding, the slanted lines of the stems, another set of slanted lines belonging to the hydrangeas, the curved, slanted and straighten lines of the hanging decoration, and the slanted and curved lines of the shadow casted by the hanging decoration. 

In terms of shapes, they are as follows: you have the tick rectangular shape of the siding, the thin shape of the stems, the curved and indented shapes of the hanging decoration, the rounded, pointed, and straighten shapes of the shadow, and the small, folded shapes of the hydrangea. 

In terms of the size, you have the rather large yet thing size of the stems, the small yet detailed size of the hydrangea, the broad and elongated size of the siding, the jagged size of the decoration, and the condensed size of the shadow.  

B). There is a lot of movement taking place in the photo. For example: when one looks at the photo, the eyes are instantly drawn to the hanging decoration. Therefore, causing movement. Why are the eyes drawn to the decoration? Because the stems, though skinny in shape, arch-up towards the decoration, pointing the eyes of the viewer in the direction of the decoration.