Bee Balm! Such interesting flowers and sizes and shapes and colors! Hmm or Columbine. Or Lilac. Or Butterfly Bush. Or...eeek! xD
Korean Hyssop for the fragrance, flowers and bee appeal. In fact, I just posted a picture of one in my garden yesterday.
Although it's not a native, (its only negative, IMO/E) it would still be hard to not choose Lantana. It's one of the first and last blooming nectar plants, and always being visited by butterflies and hummers, doesn't require me to do anything unless I visually want to remove last years' growth, when a harsh winter knocks them back to the ground. Some years I do, some years I don't. It has a polarizing scent, but I'm one of those who like it. I've never pulled a Lantana sprout and may have a sterile cultivar. Planted in yard years before I got there, though it's not the kind of neighborhood where store-bought plants are common. It propagates extremely easily from cuttings.
Geraniums. I have thought and thought about this. They are as hardy as can be for an annual, they keep on blooming, they are pretty much disease and pest free, hardly ever set a seed, come in an array of colors, incredibly low maintenance.....
I can't believe I missed this one when it was new... I just can't pick one favorite with so many that I love...but if I really had too it would be the Alstroemeria...it cannot winter here because we get too cold so every spring/summer I buy a couple plants and put them on my back steps on the patio. You never know what the nursery will have but I like the ones with the variegated leaves the most. You can find them in a covered, sometimes heated building at the nursery, depending on our weather. Alstroemeria... ( photo / image / picture from Sherry8's Garden ) Alstroemeria ( photo / image / picture from Sherry8's Garden )
I didn't reply to your question because I couldn't name just one. Maybe it would help if you asked 'what is your favorite spring flower, summer flower, and fall flower'. In fact, I'd enjoy hearing what everyone would say!
