Just like the names say, Thanksgiving Cactus, Schlumbergera truncata, blooms around Thanksgiving. Christmas Cactus, Schlumbergera bridgesii, blooms around Christmas.
The leaves of a Thanksgiving Cactus are flat and wide with serrations on the leaf edges. The leaves of a Christmas Cactus have smoother edges.
Both Thanksgiving and Christmas Cactus are easy care plants that can bloom for many weeks. There are several things that play a key role in helping a Thanksgiving Cactus to bloom at the right time. It is a thermo-photoperiodic plant, so starting about 4-6 weeks before you want it to bloom, it needs 12 hours a day of light and 12 hours a day of total darkness. During this time, the ideal night- time temperature should be 50-60 degrees. Reduce your watering slightly and do not soak the soil, only moisten the top few inches. Although a Thanksgiving Cactus needs fertilizer
when actively developing leaves, once the buds appear, do not feed the plant. Remove dead flowers to help the plant continue to bloom.