The 22-year-old was one of the 49 people killed at Pulse nightclub on June 12, and worked at the Wizarding World of Harry Potter at Universal Studios.
"To Luis, who died for love," Rowling said in a handwritten note, which was attached to the floral tribute. "You will never be forgotten."
Photographs showing the British writer's heartwarming gesture were posted online. A representative for Rowling confirmed she had sent the wreath.
"It was a beautiful gesture to see J.K. tweet about him," Vielma's friend Alma Almaraz Retana told BuzzFeed. "And when I walked in to church and saw the beautiful flowers that she has sent I knew he was in heaven dancing of happiness."
Multiple tributes have been paid to Vielma, who operated the theme park’s Forbidden Journey ride. Perhaps most touchingly, dozens of friends gathered outside the park's Hogwarts Castle on Monday to raise their wands in remembrance.