Some of Mark Preston’s collection of forest cacti.

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Drunkard’s dream, coral cactus, mistletoe cactus … when it comes to romantic common names, the trio of forest cacti types we’re covering in this episode really outdo themselves. Hatiora, Rhipsalis and Lepismium may not be plants you can pick up in your local supermarket, but these epiphytic (and sometimes epilithic - grown on rocks) cacti are enormously rewarding and fun to grow. Forest cacti expert Mark Preston is back with me this week to talk about these plants, and more generally how to propagate forest cacti.. He’s an expert on the Rhipsalidae tribe and a member of the British Cactus and Succulent Society.

Check out the notes and images below as you listen to the show…If you missed the first part of my interview with Mark Preston, discussing Christmas and Easter cactus, do go back and have a listen before you start this episode.

Rhipsalis oblonga in flower. Photograph 阿橋 HQ on Flickr. — *Rhipsalis oblonga* in flower. Photograph **阿橋 HQ** on Flickr.

Rhipsalis cereuscula or coral cactus in flower. Photograph: salchuiwt on Flickr. — *Rhipsalis cereuscula* or coral cactus in flower. Photograph: salchuiwt on Flickr.

Rhipsalis, Hatiora and Lepismium

There are 35-40 species in Rhipsalis genus including the very popular R. baccifera which is often known as the mistletoe cactus, R. cereuscula or the coral cactus, and R. oblonga (pictured). There care is fairly similar to the Schlumbergeras Mark Preston discussed in episode 84.
Hatiora is a small genus, containing H. cylindrica which has yellow flowers, carmine pink-flowered H. herminiae and H. salicornioides, which is known as drunkard’s dream and dancing bones.
Lepismium is a genus of five or six species, most of which are not very easy to get hold of commercially. However, one species often appears in mixed cactus collections - L. warmingianum: it produces masses of white flowers in spring.
L. cruciforme has been grown for many years, and produces many small white flowers; a more recent discovery is L. floribundum, which produces lots of pale pink flowers that are twice the size of L. cruciforme and scented too.

Hatiora salicornioides or drunkard’s dream. Photograph: Forest and Kim Starr on Flickr. — *Hatiora salicornioides* or drunkard’s dream. Photograph: Forest and Kim Starr on Flickr.

Forest cactus propagation

When you are taking cuttings, aim to remove a section of stem around 10cm long. If you are using scissors or a knife, sterilise it between taking cuttings of different plants to avoid the spread of viruses (you can do this but holding them under a naked flame for a few seconds, or using a disinfectant such as Citrox. If you are taking cuttings of a plant with short stem sections, you can twist these off by hand which avoids risk of virus transfer.
With desert cacti and succulents, it’s important to let cuttings ‘callus over’ for a few days after they are removed from the plant, so the wound can dry up. Does this apply to forest cacti? Well, sometimes.
For bigger, chunkier cuttings, Mark advises that you can let them callus over but it’s not as important - they are more adapted to dropping off and rooting around the place in their native home.
When it comes to thinner stems with less water reserves, you can’t afford to leave them lying around to callus, as they will wither, so crack on with rooting them straightaway.
Plastic bags a very good (and simple!) way of rooting forest cacti that Mark prefers. Take your cuttings then wrap them up in a plastic bag (one of those ones with the ‘zip’ opening is ideal) with a tiny bit of water and put them somewhere out of direct sun until the roots appear. This method is much less likely to suffer from fungal diseases than if you put them into compost straight away.
Some growers swear by other methods, including rooting cuttings in inorganic media such as damp pumice or perlite/vermiculite. Take lots of cuttings and you can experiment with what works best for you.
Whichever method you use, speed of rooting will depend on the time of year. In spring and summer when plants are raring to go, may see root buds appearing in 10 days: as soon as you’ve got a bit of root growing, you can pot them up - over winter it may take longer.
If you have two or more Schlumbergeras you can try cross-pollinating them to produce seed. (They are not self-fertile which is why you need more than one plant). Encourage them to set seed by putting flowers against each other to encourage pollination. Then you can harvest and sow the ripe seed.
If your cuttings (or indeed your forest cacti plants) turn reddish, that means the plant is under some kind of stress - it could be too much light, too much water, or something else. Once you have identified that your plant is under stress, you need to work out what has gone wrong: although as Mark points out, forest cacti are slow to respond to stress, so think back to what was happening to your plant a few months back…

Lepismium cruciforme in flower. Photograph: Megan Hansen on Flickr. — *Lepismium cruciforme* in flower. Photograph: Megan Hansen on Flickr.

Question of the week

Alexander emailed to say he has been struggling to get hold of Christia obcordata, aka the butterfly plant, in the US. It’s not surprising, really, as it’s one of those ‘it’ plants that appears on a lot of those annoying listicles you see all over the net (like this one).

This plant’s appeal is obvious: its paper leaves really do look like the wings of a swallowatil butterfly, it’s variegated and very Instagrammable. But it isn’t widely available, by any means. Yes, there is seed for sale on eBay, but I wouldn’t generally trust seed that’s coming from China as it’s very often not what it says on the packet. So where can you get hold of this plant?

I put out a request on Twitter which did garner some useful information. Former guests of the show Mike Clifford said he got seed from Top Tropicals in the US but sadly they are currently out of stock.

If you do manage to get hold of the butterfly plant, I sincerely hope you can keep it alive. It needs warm conditions and high humidity, which I suspect makes it a bit of a diva in the average home. You can grow it outdoors if you live somewhere tropical or subtropical, and according to this blog it’s tougher than you might think. Interesting fact: this is a member of the pea family so it has nitrogen fixing nodules on the roots and is reportedly grown as a fertility-boosting cover crop in Japan.

Want to ask me a question? Email ontheledgepodcast@gmail.com. The more information you can include, the better - pictures of your plant, details of your location and how long you have had the plant are always useful to help solve your issue!

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