A holiday favorite! Huge, fiery red blooms open atop 18-24″ stems creating a festive feel. Amaryllis flowers make a wonderful holiday giftand Merry Christmas Single Amaryllis is a popular choice year after year. It’s one of the best red amaryllis we’ve found. Most amaryllis bulbs bloom about 6-8 weeks after planting. If you want festive red blooms for the Christmas holidays, plant Merry Christmas Amaryllis around the end of October to early November. For Thanksgiving blooms, plant the bulbs around the beginning of October.