They never bloom

[Gail]

I have a couple cactus that have never bloomed and am looking for advice on what I might need to do for them.

First is a Acanthorhipsalis monacantha that I've had for about 1.5 years. It came from a big box store and was in rough shape when I got it. Its doubled in size since I bought it but I'd love to see some flowers on it.
I've not done much to it besides giving water and light. Repotted today and its spending the winter on a light stand with the african violets. This is the same stand my Christmas cactus lives on and blooms on. Summers are spend outside on a covered porch. The room its in is warm

Second one is possibly a Rhipsalis pilocarpa, I need blooms to properly ID it. I've had it for a year now, I've not repotted it since I got it. It has grown a huge amount and appears quite healthy. This summer was spent outside on the porch in bright direct sun. For the winter its in a East facing window, its color has washed out a little since being inside. In the summer its much greener. The room its in is cooler.

[oldcat61]

Gail, my pilocarpa is blooming like crazy right now. Where are you located?

[Gail]

I'm in North Idaho, close to the Canadian border.

[greenknight]

You ever let them go dormant? Cacti generally need at least a semi-dormant period to set buds. Acanthorhipsalis monacantha is a spring bloomer, so I would think reduced watering in the winter would be the thing.

[Gail]

I reduce watering in the winter but maybe it needs even less. I have a room I can move it to thats cooler and is only lit by natural sun, no late night lamps running.

[oldcat61]

Gail - just to confuse you: all my various rhipsalis are in the GH, (so no artificial light) which stays above 50 in the winter. I treat them like my epis, with rich, well draining soil kept slightly moist all year. The winter bloomers are all going crazy right now. Tiny flowers but anything on these cold dreary days is so welcome. Sue

[cjbaker]

Many of my cacti finally started blooming when I dramatically increased their sunlight in summer and fall. My understanding (correct me if I'm wrong here) is that you want the plant to build up as much stored energy (sugar, I presume) as possible from sunlight right up until it goes dormant. As soon as the sunlight is reduced (when I bring mine inside), you don't want any more growth until spring, or it will use up the stored energy. If you see new growth during the winter, that means it's using up its energy store. If the concentrated energy remains when growth starts again in spring, it can produce flowers. Do you typically see any growth over winter?

Also, you don't want soil that's too rich, or to use too much nitrogen fertilizer, because it will encourage green growth instead of flowers. Perhaps this is the case with your A. monacantha? I have never grown this genus though, so oldcat's advice on soil is probably best. I also wonder if watering too much during the growing season can promote green growth at the expense of flowers.

[oldcat61]

Keep in mind that all cactus are not alike in their growing or blooming seasons. My rhipsalis kind of just "sit there" in the summer but start growing & then blooming when it gets cool. Most of them don't want full sun in the summer unless you like that bronzed, burned look. Word of advice: when these guys are happy they can take over a GH. Wish I had other cactus nuts nearby so I could hack off pieces. I have an elliptica that wants to eat small children. Sue

[Gail]

Neither have any new growth so maybe they will bloom next spring. I'll keep doing what I am now to keep them dormant, thanks for the advice.

[DaveW]

If your fertilising the plant, as Craig says try a low nitrogen fertiliser so you don't promote growth at the expense of flowers. Tomato fertilisers or those designed for flowers or fruit rather than general fertilisers are usually lower in nitrogen for this reason.

[Gail]

I'm not currently fertilizing but I'll keep the low nitrogen in mind for when I do:)

[oldcat61]

Gail - I doubt they'll bloom in the spring. Most rhipsalis are winter blooming. Here's a shot of my elliptica. Sue

[cjbaker]

Lovely flowers Sue, not like any of my cactus flowers. It's so cool how they come out of the "pads", I suppose those little indentations are areoles.

[greenknight]

Yes, Rhipsalis pilocarpa should be blooming now, but Acanthorhipsalis monacantha is a spring bloomer.