It is no lily, but it does live on the banks of the Nile River. Lily of the Nile, Agapanthus africanus, endures both long dry summers and winter flooding. While inundated, it clings to the silty soil with a sturdy network of rubbery roots. Densely mounding foliage regenerates as floodwater recedes. If conditions get exceptionally warm and dry, foliage may eventually shrivel after midsummer bloom.
Home gardens are certainly more hospitable than the floodplains of the Nile River. The luxuriant foliage of lily of the Nile is evergreen locally, even if irrigation is minimal. The rubbery leaves get as long as two feet, arching outward from basal rosettes. New foliage obscures deteriorating old foliage. Plants that get too congested to bloom well might benefit from division of individual rosettes.
Lily of the Nile blooms around Independence Day, with round floral trusses that resemble exploding fireworks. Each blue or white bloom stands about two to four feet high, on slim and bare stems. Individual florets are small and tubular. ‘Storm Cloud’ blooms with darker blue or purple. Agapanthus orientalis may exhibit bigger blooms and coarser foliage. ‘Peter Pan’ stays low and compact.