The clue “Flower showerisVASE” is referring to a type of wordplay commonly used in crosswords called a homophone. A homophone is a word that sounds the same as another word but has a different meaning and spelling. In this case, “flower shower” sounds like “flourish hour,” which can be interpreted as the time during which something is flowering or flourishing. The second part of the clue, “isVASE,” is the solution to the crossword. A vase is a container commonly used for holding flowers, so this is a play on words that uses the homophone to lead the solver to the intended answer.