A young zigzag cactus, whose stems are just starting to arch down. Photo: crocus.co.uk
Certainly one of the strangest looking cactus, the zigzag cactus or fishbone cactus, Epiphyllum anguliger, now more correctly Disocactus anguliger, has been around for years, but suddenly seems to be catching on in a big way.
You may also see it labeled “mini fishbone cactus”. However, it will turn out to be more medium-sized than mini, with the whole plant eventually reaching about 2 to 3 feet (60 to 90 cm) in diameter. Still, this is small for an “orchid cactus” (the common name used for cactus of the genus Epiphyllum and their relatives); many orchid cactus have individual branches that measure over 6 feet (2 m) long! The smaller size of the zigzag cactus makes is a more convenient houseplant than some of its rangy cousins.
It’s obvious where it gets its common name! Its stems are very curious: flattened, yet succulent, they are deeply and alternately toothed, giving the stem a zigzag appearance. The lobes are also the origin of the plant’s name: anguliger means “angle bearing”.
The stems are green (although older stems can become woody and brown at the base) and carry out the plant’s photosynthesis, since, like most cactus, it has no leaves. A lot of people mistake the broad, flat stems for leaves, but the only leaves this plant ever produces are the first two leaves (cotyledons) of its seedlings and they’re long gone by the time you pick up a plant at the nursery.
E. anguliger is from Mexico, where it grows in evergreen oak forests in mountains along the Pacific coast, but not on the ground. It’s an epiphyte: it grows on tree branches, way up near the crown of the tree. The branches arch out from the base of the plant, then a down, making it a good choice for hanging baskets.
Two other curiosities. First, unlike most other cactus, the zigzag cactus is spineless. Secondly, you may also see aerial roots growing underneath the stem when the humidity is high. In the wild, the plant uses them to root onto other tree branches and thus spread. In your home, their only purpose is to make you ask questions.
When you’re sold a “zigzag cactus”, it’s generally a pot of rooted cuttings and you buy it for its attractive and unusual form. There is no mention of the spectacular flowers to come. But by the time the plant is 3 years old or so (and that’s young for a Epiphyllum), it will begin to bloom, usually in the late fall, then sometimes a second time months later. The flowers are borne from tiny areoles (cushiony white growths) at the base of the stem’s teeth.
The bloom starts as a tube up to 8 inches (20 cm) long that opens into a cup-shaped pure white flower with pale yellow or orangey outer “petals” (actually sepals). At about 4 inches (10 cm) in diameter, they are smaller than most other orchid cactus, but proportionate to the size of the plant.
The blooms are strongly and deliciously scented, but only at night. It takes only one to perfume the entire room and several together are enough that you can smell the bloom throughout the house. It’s my wife’s favorite perfume and if you could put it in a bottle, you’d probably make a fortune! Of course, in nature, the perfume isn’t designed to attract humans, but rather to draw moths, the plant’s main pollinators, from afar.
Although I keep reading that the flowers last only one night, in my house, they last two, staying open the day in between, although odorless during the daylight hours. They fade at the beginning of the next day. Most are produced simultaneously although a few may be a day or two ahead of or behind the others.
I’ve never taken the time to hand pollinate the flowers, but inevitably a few fruits form after each flowering. They take months to ripen; 6 months or more. They are green, ovoid and about 1 ½ inches (3–4 cm) thick. It’s hard to tell when they are ripe, but I harvest them when they turn a bit yellow and are soft to the touch and that seems to work well enough.
The flesh inside the fruit is translucid and gelatinous with numerous tiny black seeds. Scoop out the flesh: it’s absolutely delicious and tastes much like a pitaya or dragon fruit (Hylocereus undata or a similar species): not surprisingly, since it is a close relative.
A Zigzag Cactus Doppelganger
Not so long ago, the main zigzag cactus on the market was a different species, also called fishbone cactus or rick rack cactus: Selenicereus anthonyanus, formerly Cryptocereus anthonyanus. It has similar flat stems with the same pattern of alternating extended teeth, but it’s a much bigger and less elegant plant, and also reluctant to bloom. The flowers, if it ever does bloom, are twice as big and purple on the outside, pink, yellow or white inside. Like those of its cousin, they’re highly scented after dark. And they do last only one night.
S. anthonyanus is not in style currently, but is sometimes found in specialist cactus nurseries. If you have the space for a monstrously big spreading plant, it can certainly be impressive!
The zigzag cactus is a tough plant, very easy to grow.
Indoors, it prefers moderate light with a few hours of direct sun daily in the summer. It would be fine in front of an east window, for example, or somewhat back from a hotter south or west one. Full sun all day is fine in the fall and winter in temperate climates.
Give it normal indoor temperatures, although it will tolerate cooler winter conditions, down to 40 ºF (4 ºC), as long as it’s kept very dry. It’s tolerant of both high and low atmospheric humidity.
Water as needed when the soil dries out, thus more often in summer than in the winter.
Fertilize lightly from spring through early fall with whatever fertilizer you have on hand.
A summer outside in partial shade is helpful. It helps recreate the moving air of the zigzag cactus’ natural environment. Just acclimatize your plant first by setting it in full shade for a few days, then in slightly brighter shade. It will especially like the dappled shade of an overhanging tree.
A zigzag cactus can live for years in the same pot, with only an occasional top dressing: scraping off the soil at the top and replacing it with fresh mix. It doesn’t mind being in a small pot—after all, in the wild, its roots are limited to a bit of leaf litter on the bark of tree—but you may eventually need a heavier pot to hold it up. When you do repot, any well-draining soil will suffice: regular potting soil, cactus mix, orchid mix, etc. I use regular potting mix to which I add about ¼ orchid mix or perlite for extra drainage.
Don’t hesitate to prune off damaged and old stems: even if you cut your plant back nearly to the soil, it will sprout and regrow.
Well, you could harvest the tiny seeds from the fruit and sprout them, but they’ll be a long way from a mature, presentable plant and some 7 to 8 yers from blooming. Or you could divide a mature plant.
Generally, though, it’s simpler to just insert 3 or 4 stem cuttings about 6 inches (15 cm) long into a 10 cm pot and keep the potting mix slightly moist. This is best done in spring or summer. Rooting hormone can be used, but isn’t absolutely necessary.
Rot is the main enemy and usually results from soggy soil, so make sure you let the soil dry out before watering again. The zigzag cactus is not a desert plant, but neither does it necessarily need weekly watering. Touch the soil and let your finger be the judge. If it’s dry, water; if not, wait! In case of rot, which will see the plant start to collapse while the soil will smell like a rotting potato, start a new plant from cuttings from a still healthy stem or two.
Reddish stems in summer are not a problem: they’re like a sort of natural sunscreen and are the plant’s reaction to excess light. It reddens in its natural habitat as well. A bit of reddening actually leads to more bloom later on.
The main insect concerns are mealybugs and scale insects; less frequently aphids. You could try spraying with insecticidal soap or a half-and-half solution of isopropyl alcohol and water, but the best control is to keep your cactus far from any infested plants.
Slug or snail damage is possible if the plant is put on the ground outdoors. Hand pick the culprits … then hang your plant from a tree, out of the reach of molluscs.
The zigzag cactus: exotic and unusual; you’re going to love it!