What to do with a Root-Bound Christmas Cactus
I have 3 Christmas cacti that need to be repotted( root bound) I am wondering if I can trim the roots and put them back in the same pot?
I wouldn’t recommend trimming the roots. There are better ways to handle a root bound Christmas cactus. The best time to deal with a root bound Christmas cactus is late winter or early spring after it has finished flowering for the year. If you really think it is necessary for the health of the plant to do it right now, here are some suggestions. (Just remember the plant may not bloom this year).
You can carefully divide the root ball by gently pulling it into two sections. Plant one section back into the original pot, adding some fresh, new, acidic soil that drains well, and start a new plant with the other section using the same type of soil. The 2nd container should be the same size or smaller than the original container and have drip holes in the bottom. These new plants will take longer to dry out so be careful not to over water.
Another option is to re-pot the entire plant into a slightly larger container with drip holes in the bottom. Do not use a pot that is more than 2″ larger than the original pot or the roots will stay wet too long and rot. Remove your Christmas cactus from its pot and loosen the soil around the roots. When you plant the Christmas cactus in its new pot, the top of the root ball should be about an inch below the rim of the pot. Fill the pot with a rich acidic soil that drains well.