Agastache foeniculum "Licorice Blue," or Anise Hyssop, is another perennial that the hummingbirds, butterflies, and bees will thank you for.  Growing to about four feet, Anise Hyssop has dark green,
anise-scented leaves and spikes of violet/blue flowers.  It is long blooming and puts on quite a show in late summer, and it often re-blooms if cut back.  Anise Hyssop is used for its color and scent in potpourri and dried arrangements and for its taste in tea and as a seasoning.  Sun,  Zones 3-9.  Quarts. (Photo attributed to Wayne Ray, Wiki Commons, and in public domain)

(See photo of this colorful Anise Hyssop here)  If there is a perennial that can brighten a dreary day and fool you into thinking the sun has come out, it is Agastache x "Golden Jubilee."  Growing three to four feet tall,  this colorful Anise Hyssop's chartreuse leaves are what make it a knock-out.  The bright purple, bottle brush blooms (say that three times fast) of "Golden Jubilee" are just a bonus, but they are especially striking against the bright-leaved foliage.   Everyone loves this perennial Anise Hyssop:  all the people who see it and every butterfly, hummingbird, and bee I have ever met.  Agastache "Golden Jubilee" is highly adaptable to sun and shade, although some shade is advisable, as it protects the color of the foliage.   Zones 3 to 8.  Quarts.