Hydrangea 'Endless Summer'...depending on soil acidity or alkalinity the flowers can range from blue(acidic) to pink(alkaline). Ours are always a mix as seen here. The young blossoms start out a white/green (lower right) before maturing into their final colour.
At the butterfly garden where I work, I get asked pretty much every day which nectar flowers are best for butterflies. There are a few plants that fit this bill very well, and at the top of the list is Pentas lanceolata, known more commonly as Penta or Starflower.