The Collaborative International Dictionary of English v.0.48:

Flowering \Flow"er*ing\, n.
   1. The act of blossoming, or the season when plants blossom;
      florification.
      [1913 Webster]

   2. The act of adorning with flowers.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Flower \Flow"er\ (flou"[~e]r), v. i. [imp. & p. p. Flowered
   (flou"[~e]rd); p. pr. & vb. n. Flowering.] [From the noun.
   Cf. Flourish.]
   1. To blossom; to bloom; to expand the petals, as a plant; to
      produce flowers; as, this plant flowers in June.
      [1913 Webster]

   2. To come into the finest or fairest condition.
      [1913 Webster]

            Their lusty and flowering age.        --Robynson
                                                  (More's
                                                  Utopia).
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            When flowered my youthful spring.     --Spenser.
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   3. To froth; to ferment gently, as new beer.
      [1913 Webster]

            That beer did flower a little.        --Bacon.
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   4. To come off as flowers by sublimation. [Obs.]
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            Observations which have flowered off. --Milton.
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The Collaborative International Dictionary of English v.0.48:

Flowering \Flow"er*ing\, a. (Bot.)
   Having conspicuous flowers; -- used as an epithet with many
   names of plants; as, flowering ash; flowering dogwood;
   flowering almond, etc.
   [1913 Webster]

   Flowering fern, a genus of showy ferns (Osmunda), with
      conspicuous bivalvular sporangia. They usually grow in wet
      places.

   Flowering plants, plants which have stamens and pistils,
      and produce true seeds; phenogamous plants; --
      distinguished from flowerless plants.

   Flowering rush, a European rushlike plant (Butomus
      umbellatus), with an umbel of rosy blossoms.
      [1913 Webster]

WordNet (r) 3.0 (2006):

flowering
    adj 1: having a flower or bloom; "a flowering plant" [ant:
           flowerless, nonflowering]
    n 1: the time and process of budding and unfolding of blossoms
         [syn: blossoming, flowering, florescence,
         inflorescence, anthesis, efflorescence]
    2: a developmental process; "the flowering of antebellum
       culture" [syn: unfolding, flowering]

Moby Thesaurus II by Grady Ward, 1.0:

103 Moby Thesaurus words for "flowering":
   accomplishment, advance, advancement, amplification, anthesis,
   balmy, bloom, blooming, bloomy, blossom, blossoming, blow, blowing,
   booming, budding, burgeoning, clear, crescent, developed,
   development, developmental change, efflorescence, efflorescent,
   elaboration, enlargement, evolution, evolutionary change,
   evolvement, evolving, expansion, explication, exuberant, fair, fat,
   floral, floreate, florescence, florescent, floriate, floriated,
   floricultural, florid, flourishing, flowerage, flowered, flowery,
   fruiting, full bloom, full-fledged, full-grown, fully developed,
   furtherance, garden, going strong, gradual change, growing, grown,
   grown-up, growth, halcyon, horticultural, hortulan, hypertrophied,
   in bloom, in blossom, in flower, in full swing, in good case,
   inflorescent, juvenal, juvenescent, juvenile, maturation, mature,
   multiflorous, natural development, natural growth,
   nonviolent change, overdeveloped, overgrown, palmy, piping,
   progress, progression, prospering, radiciflorous, rhizanthous,
   ripening, rise, rosy, sleek, sprouting, thriving, unfolding,
   unfoldment, uniflorous, upgrowth, vigorous, young, youngling,
   youthful, youthlike, youthy