Unlike many other houseplants, the Christmas cactus (Schlumbergera × buckleyi, USDA plant hardiness zones 10 to 12) produces an abundance of flowers. Dividing or propagating this plant is an easy way to fill your home or office with cheerful flowers. Divided Christmas cacti also make great gifts, especially around the holidays when they tend to be in full bloom.
When dividing a Christmas cactus, you'll preserve the existing root system as much as possible while separating the plant into distinct sections. When propagating this plant, you'll grow roots from a single leaf and plant it in soil several weeks later. Even if you don't want to divide or propagate a Christmas cactus, it should be repotted every few years to give its roots room to grow.
Dividing a Christmas Cactus
It's best to divide a Christmas cactus during a period of dormancy rather than during a period of growth, so wait until the flowers have fallen off. Gently remove the entire root ball from the pot by grasping the base of the plant and wiggling it free. If possible, tip the pot to get a helping hand from gravity.
Shake some of the dirt off the root ball so that you can easily identify the main stems and the roots. Using a clean, sharp knife, cut roots that you can't disentangle by hand. You can transplant any stem that has roots attached to it. Use the "propagation by cutting" method to stimulate root growth on any stems that don't have roots.
The Christmas cactus grows best when its roots are somewhat restricted. Therefore, it's best to choose small pots that will allow not more than an extra inch of soil on all sides of the divided sections. Shake off some of the old dirt from the roots before planting it in fresh cactus or succulent potting soil. Water well immediately after replanting.
Propagating Christmas Cactus Cuttings
You can grow an entirely new Christmas cactus with just one leaf from a healthy plant. Let the bottom of the leaf rest in about half an inch of water and place the cup or bowl in a sunny window. Change the water daily to prevent it from getting stagnant.
Within six weeks, the leaf should sprout roots about 1 inch long. You can then transplant and care for it like any other Christmas cactus.
Repotting a Christmas Cactus
If you like the full, thick growth of your Christmas cactus but suspect it has outgrown its pot, you can revive it by repotting it rather than dividing it. This will give its roots a little more room to grow and allow you to add fresh potting soil, which will provide additional aeration, drainage and nutrients. All of these factors will help perk up the cactus and encourage new growth.
According to Clemson Cooperative Extension, repotting is necessary every three years or so. As with dividing, wait to repot a Christmas cactus until the plant has finished blooming and the flowers have dropped off. Use the same recommendations for choosing a pot size and potting soil.