The shape of the flower attracts hummingbirds, (rather than the common myth that the color brings them to feeders) so your garden will be buzzing all season long with any color of this design. They come in the following colors (ball color + flower color): Orange + red, Yellow + Orange, Lime Green + Aquamarine, Aquamarine + lime, Cobalt Blue + Purple, and Purple + Fuschia.
It is the responsible thing to do to clean your feeder weekly with a light bleach water solution (one drop of bleach, fill with water, soak and rinse thoroughly), to keep harmful bacteria from growing in the vessel. Also, stop feeding the hummers in late August to September depending on the migration of the hummers in your area, this encourages them to migrate rather than staying until the weather is too cold for them to survive. This info, and hummer nectar recipes are available online.