Questions & Answers about En frisk blomst på bordet forbedrer helsen, sier legen.
Norwegian adjectives follow weak vs. strong declension patterns. Here frisk modifies an indefinite singular common-gender noun (en blomst), so it takes the weak form with no ending.
• If it were neuter: et friskt eple (adds -t).
• If it were definite or plural: de friske blomstene (adds -e).