In August in USDA zone 7, the African native, Amaryllis belladonna is indeed a surprise.
An equally beautiful surprise lily for the north is the Resurrection Lily, Lycoris squamigera from Japan or China
We are especially grateful for their lovely pink blossoms of Surprise Lilies this year and would have understood if they skipped blooming with the unbelievable heat and drought. But, here they are reliable and beautiful.
There is a 1943 article by Elizabeth Lawrence online here. She discusses the bulbs she and her mother were experimenting with in their N.C. gardens.
So if you decide you want pink beauties in your late summer garden, be sure to get the right one: Lycoris for north of zone 7 and Amaryllis for zone 7 and above.