Crab cactus can also bloom during the holidays 

Q: I’ve had the same “cactus” for over 30 years. I’ve never done anything to it other than cut it back and water it. I’ve never had to “force” it to bloom. Every year it blooms like this. I read your article, but still can’t tell if it’s a crab or Christmas cactus. Thank you. — K.A., Albuquerque

A: From the photo, I am confident you have the variety Schlumbergera truncata or crab cactus. It might have been labeled as a Zygocactus truncatus when it was purchased all those years ago.

Here’s why I’m so sure that yours is of the crab variety. I want you to notice how, on each leaf segment or joint near the end, you can see pointy protuberances on each joint. They aren’t separate, it’s just the way the joint grows. 

Those wee pointy parts that look like crab pincers, if you will. No, they don’t have spines and won’t hurt you, it’s just that they look like crab parts. 

I suppose that S. truncata is a sturdier variety and easier to propagate which is why, nowadays, most of the Christmas cactus you see for sale are, in my opinion, really crab cactus. They bloom just like their cousin. And since they bloom at the correct time and look so like their cousin, they are simply sold as Christmas Cactus. Which isn’t wrong — they sort of look like cacti and are in bloom during the Christmas holiday season. 

In my “Western Garden Book,” the “real” Christmas cactus is named Schlumbergera bridgesii. This variety doesn’t have the pointy protuberances on the joints. Their edges have a scalloped look to them, no pointy parts on the leaf joints. 

So yes, you have, in my opinion, a crab cactus.

Q: I just received a sweet small ficus tree as a gift. It’s very young, living in a 6-inch pot, but I think I saw a couple of fungus gnats fly out of it when I was bringing it home. How should I treat the plant so I don’t have trouble later? — L.P., Albuquerque

A: Here’s what I’d suggest. 

First I’d fill the kitchen sink a scant third full of tepid temperature water and stir in no more than a tablespoon of dish detergent. Then I’d set the ficus pot in that warmish water and slowly, using a cup measurer or plastic cup, pour the soapy water on the soil. 

Be sure to turn the pot while it’s in the sink so all the soil gets a soapy water drench. 

Once you are confident that all the soil has been drenched, let the plant — pot and all — sit there for about a half hour. Then do it again. Douse the soil with the soapy water. 

When you are done with the second drench, unstopper the sink and allow the pot to drain for several minutes. Once you are pretty sure most of the water has drained away, set the pot on a clean saucer. I would aim to keep the new plant in a certain state of quarantine for a couple of weeks to see if it’s still harboring any more of the fungus gnats. If you need to treat again, do. 

I hope that one good soapy water drench will eliminate any pesky fungus gnats and that the ficus has found a new and happy home. 

Happy Diggin’ In and Happy New Year to us all!

Tracey Fitzgibbon is a certified nurseryman. Send garden-related questions to Digging In, Albuquerque Journal, 7777 Jefferson NE, Albuquerque, N.M. 87109, or to features@abqjournal.com.