Amaryllis flowers are hard to categorize. The tropical and exotic look of the flowers is one of the reasons people like growing them. Amaryllis flowers are easy to grow and forcing them to bloom indoors is a snap. You can buy them boxed, potted and ready to grow by just adding water. It takes Amaryllis flowers about six weeks or longer to bloom. The plant can grow up to two feet. The flowers are big, bright, trumpet shaped blooms that can cheer up any indoor garden scene.