You have Cereus peruvianus monstrose cv. 'Rojo.

Here is mine.

Christopher

Thanks Christopher. Yours looks great!

-Erica

Oh, that looks like one I have that I didn't know what it was. It started out just a tiny crest, and has been growing like crazy. Looks completely different than when I bought it about a year ago! Do you think it's the same kind?

Leslie - Certainly looks the same! It grew that much in a year? How much sun has your been getting? It may be slightly etiolated.

I am hoping to keep mine smaller if I can. This is the first cactus I have ever owned so I am not sure how to achieve this, it at all.

Christopher - Do you know if these can be pruned in any way to maintain a specific size?

-Erica

Mine is outside, southern exposure with an overhang. It gets a lot of sun in the winter, not as much in the summer. It may be a little more than a year, I'm not sure what month it was. But yeah, its been growing like nobody's business, it's a happy camper!
If its a Peruvian cereus, they get pretty huge, but if you want to keep it smaller, keep the pot on the small side.

Erica, yes and now or the next few months are the time to do it. Just remove the segment(s) that you want; those, of course, will be extra plants in short order and ready themselves for rooting and potting. They're all very nice plants pictured here, particularly when you think of the regular (non-cristate/mostrose) C. p. and the size it gets (many meters high).

If I could keep mine outside I would love to let it grow! Unfortunately my space near adequately lighted windows is limited and I have some pretty chilly winters!

-Erica

Hence your want for some slicing and dicing - it's a great idea and quite a suitable plant for cactus bonsai - naturally jointed for a suggestive cutting.

Any suggestions or tips for pruning these? Mostly concerned with how the main plant heals after such an intrusive cut. I will wait to see how it grows this summer but I don't see myself doing any of that until next summer.

-Erica

Erica, the plant I have is from a cutting I took from a larger plant I had. When I was given the original plant, the previous owner had already removed a few cuttings, and the scars where they were taken were quite noticeable. I have to say it did bother me a bit.

Jeff is right, it is a good plant for taking cuttings from, as it produces multiple growing points, but bear in mind that it will affect the look of the plant. If that doesn't bother you, then prune away.

Christopher

That is definitely a concern of mine, thanks!

-Erica