From Colin Mason's patch of 'Trymlet' seedlings in his garden at Fieldgate Lane, Kenworth, found in 2012 along with another inverse poculiform G. x valentinei that became 'Fieldgate Imp'. In addition to the apical marks the outer segments of 'Fieldgate Fantasia' show strong, crisp rather wedge-shaped basal marks that are typically slightly paler within distinguishing this striking mid-season cultivar from other double-marked namings.