Haworthia spp. are just sweethearts, pretty much full-time. I get asked about them a lot at work, mainly because we have some varieties in at the moment that people don't recognize and want an ID, but also because from time to time someone sees one and finds it appealing but is uncertain about whether or not they could keep it going. The answer is pretty much always yes. Yes, you can keep it going; yes, this is an easy plant if you have any windows at all; yes, you should buy it now. This isn't salesmanship (except, I guess, in a very loose sense); it's honesty. Haworthias rule.
Now, this isn't to say that Haworthia nomenclature and taxonomy aren't horrifying, labyrinthine messes that will eat your brain until you go mad. (For an example, check out the poor soul here.1)Trying to get a solid ID on a Haworthia is the sort of thing about which people write epic poetry, or action movies.2 And then when you factor in the various hybrids (Haworthia/Gasteria, Haworthia/Aloe, Haworthia/Haworthia), it's sort of a wonder that anybody bothers to name any of these guys at all. For the average houseplant owner, this isn't really an issue, because the average houseplant owner doesn't care what they've got so much as what they're supposed to do to keep it alive;3 it's only the incredibly neurotic people who have to know the exact names of everything who are going to have problems.
Nevertheless, some of us are that neurotic, in which case it's handy to have reference sources. There are good, if redundant and incomplete, picture and ID sets available here and here. I ran across the latter of the two via A Succulent Life, so a hat tip there. I make no promises about any of the identities I attached to my photos, or about the identities attached to the photos at the abovelinked sites, but I did make every effort, and it looks to me like they did too.
I like them mainly because they're easy to care for: the H. retusa in the picture above is one I've had for three and a half years and taken a bunch of offsets from (some of which I wish I had back, actually). It didn't complain about the north window in the old apartment, it doesn't complain about the west window it's in now, and the only issue we've had that is still unresolved is, most of the leaves had a sort of "deflated" look to them the last time I checked. It's probably too wet, too dry, or too cold. I think too wet. We've been through this before.
So but maybe we should get straight to the care information.
Light: Ideally, these should have full sun indoors, though they can make do with bright indirect for a time, if they have to. Mine are about equally divided between a partly-obstructed south window and a barely-obstructed west window, and there doesn't seem to be any huge difference between the groups. I grew the H. retusa in a north window for a couple years, and that didn't appear to be a problem, either.
Watering: as with most succulent plants, too much water will kill your plant quickly, and too little will kill it slowly, so if in doubt, don't water. In the spring and fall, I let them get about halfway dry between waterings; in the summer and winter, growth slows considerably and I water only when they're pretty much completely dry. But this makes it sound complicated, when really they're pretty flexible, and hard to kill (or at least the more commonly sold species are). If you're watering when you'd call the plant "pretty dry," however you decide when that is, then you're probably getting it right. A clay pot and very lean soil that drains quickly will help too, especially for people who have a tendency to over-nurture.
Humidity, Feeding, Pests: all pretty much non-issues. I have seen the occasional mealybug infestation (not on my own plants), but that's about it. Feeding is probably desirable, but I had mine for a couple years before the idea even occurred to me, and the plant got by just fine, so it's not something I think you probably need to stress out about. If you do feed, I'd go with a pretty dilute solution of like 20-20-20 or 20-10-20, and only feed in spring and fall.
Temperature: I'm not sure about this one, actually. I wouldn't try much below 50ºF (10ºC), though it's entirely possible that they can survive quite a bit lower than that. I just don't want to say they can and then be wrong. Maybe a reader can jump in here and give me something more specific?
Propagation: Propagation for the most common varieties is almost always by way of offsets, which plants will spontaneously produce after a certain age. That said, there are some rare species that do not offset, too, and can only be started from seeds, though those species aren't usually offered for sale. (I'm trying seeds of Haworthia pumila, a species which I think does offset but which I haven't seen for sale recently, mostly just to see what that process is like, but it's too soon to have anything to tell you about that.) Getting plants from offsets aren't any more complicated than just pulling the offset and the main plant apart (ideally you should try to get leave roots on both plants, but nothing terrible is likely to happen if you don't manage to get any roots on the offset: it'll grow some, eventually. Though you do have to be sparing with the water until you're fairly certain that rooting has happened.) and then planting them separately. It does seem to help if you let the offset reach a reasonable size before separating, though I can't define what I mean by "reasonable size" exactly.
Grooming: Haworthias flower fairly readily indoors, once they're a certain age, and may even flower more than once in the same year. The flowers appear on long stalks, like those of Aloe or Gasteria, but are white, tiny, short-lived, and not especially attractive. I don't know if it's best to take the flowers off as they appear – I personally don't. Grooming for Haworthia is otherwise nearly non-existent.
Haworthias are native to Southern Africa, and some species share habitats with some Lithops species, which I mentioned in the Lithops profile. Like I said there, some of them have evolved translucent leaf tips, so that they can get light to a larger surface area without having to expose said larger surface area to drying heat and wind. Some Haworthias go further and, like Lithops, bury themselves in sand, leaving only their leaf "windows" above the sand level, which obviously protects them even more from the wind. Haworthia retusa, above, looks like it might be one of those, though of course I don't bury mine in sand because I like to be able to see my plants.
A number of different species are out there, but the one I see probably the most often is H. attenuata. This is often called H. fasciata, but apparently the actual H. fasciata is pretty rare (see Palmbob's comment here), and if you're sold one that's being called either name, it's really probably attenuata. Which is fine, because attenuata is a nice plant, and one of the more striking Haworthias. One thing I'm not nuts about: in very intense light, they'll turn sort of a muddy brown color. It's unlikely to happen indoors, and it's reversible, but it looks kind of worrisome. Also, the tips of the leaves sometimes turn light gray-brown and dry up for some reason; I'm not sure what causes this, but it's usually only on a few leaves at a time, generally the lowest ones, and the dead parts can be cut off easily enough. H. attenuata offsets plentifully, and pups are easy to root on their own.
A species I like but don't (yet) own is H. truncata; this is an unusual windowleaf Haworthia with leaves that grow in nice long rows, instead of in a rosette pattern. This sort of arrangement of leaves is common with Gasteria spp., and some Aloe spp. (like young Aloe vera), but it's unusual for a Haworthia. They're not especially pretty plants, but they are weird, and different, so someday I will probably have one.
A species I've been seeing a lot of lately (for some reason) is H. limifolia, which apparently is an old story in the succulent trade, but which I noticed for the first time last August, when I started my current job. It has sort of dull green-gray leaves with pronounced ridges across the leaves' width, which ridges have given it the common name of "fairy washboard."4 The below-pictured plant was an offset from a plant at work, and when I brought it home it had about three leaves, all of which were tiny. Recently it's been practically exploding, it's growing so fast. Palmbob at davesgarden.com says that this particular Haworthia deals well with overwatering, which is a common cause of death for the genus; this might explain why it's one of the more commonly available species.
The next one here may or may not be H. batesiana; I no longer remember where and when I saw that name, or why it seemed like the choice for this plant. Its story has a (semi-) tragic end: the base of the plant had dried up, or rotted out, or both, to the point where pieces were falling off when I would pick it up to water it, and eventually I got tired of that and cut it up to make into new plants. Good idea in theory, but in practice, few of the cuttings rooted, or even tried to, and few of the ones that did root looked like anything I wanted to have in my home. I do still have a couple of pieces of it that rooted and don't make me want to vomit when I look at them, so we may see it return to its former glory, but this is a long shot. It appears to be a trailer naturally, and self-branches. It just isn't that great at hanging on to its own stems. Oh well. Pretty while it lasted.
This last one is a NOID; I posted to Garden Web about it, and had one person suggest H. emelyae, which I do appreciate the thought (s/he was the only person to reply to the post), but I have my doubts. Even taking into account that Haworthia spp. are variable, sometimes really really variable, I have yet to see any pictures of H. emelyae that look much like this. (Mostly they're shorter, flatter, and browner, and the leaves are more triangular in cross-section.) I could accept maybe a H. truncata / H. emelyae hybrid, maybe, but even that would be kind of a stretch for me. The lighting in this picture sucks; the actual plant is pretty much a green kind of green, not the grayish green it appears to be here. There's a H. truncata var. maughanii, which forms rosettes instead of having an alternate leaf pattern like the species, and maybe that's what this plant is, but it's hard to find great pictures of it. It'd be nice if somebody could confirm or refute this for me. In any case, it's adorable, and that's what's important.
Haworthias as a genus occasionally use other, larger plants to protect them from the intense sun of their South African habitat; this has the additional benefit of protecting them from animals that might otherwise eat them. I mean, you or I might look at a Haworthia and not think, I'll bet that plant would make a delicious meal, but what if you were a lizard?5 So they're smart, kinda like Bryophyllum daigremontianum (sometimes called Kalanchoe daigremontiana), which also uses other plants for its own defensive purposes.
Haworthia spp. are also planted around homes in South Africa as protection against lightning. I think lightning rods would probably be more effective. Hell, signs saying: "Lightning: please do not strike our home. Thank you," couldn't really be any less effective. (Long, ranty digression at 6.) But it's not the fault of the Haworthias that people expect things of them that they haven't promised. What they do promise, by and large, is that they'll be a good, low-maintenance plant for a bright window, and they deliver on that.
Photo credits: my own, except the flowers, H. truncata, and Morbo, as noted in the text.
1 I kid. He and I diverge a lot on how seriously we take DNA: I think if you're going to take evolution and speciation seriously at all, DNA has to be your ultimate criterion for whether two organisms are from the same species or not. He, if I read him right, thinks that what the DNA actually cooks up, the phenotype (in the jargon), should be what gets measured and counted and analyzed, and not the DNA itself necessarily. This is, to a point, splitting hairs, but splitting hairs is kind of the raison d'être of the taxonomist. Fish gotta swim, birds gotta fly, taxonomists gotta nitpick.
2 Small portion of the unfilmed script for Haworthia: Taxonomist Bloodbath is below. I see Arnold Schwartzenegger as the Taxonomist.
Now you're just being unreasonable. It's clearly Haworthia retusa. Look at the inflorescence, for Pete's sake.
TAXONOMIST (DRAWING GUN)
No. It's Haworthia emelyae var. multifolia.
[TAXONOMIST blasts DR. BERG into bloody confetti]
TAXONOMIST (REPLACING GUN)
And I did look at the inflorescence.
3 (And some of them aren't obsessively concerned about that, either.)
4 And I suppose it could be a fairy's washboard, but when I think about tiny, mischievous, magical, flying beings in the English countryside, I don't really picture them doing laundry. I mean, surely either fairies don't have the hygiene issues that would make doing laundry necessary, or else they have some magical way of doing it. Some kind of enchanted Maytag, is what I'm picturing. Possibly a laundromat-o'-the-wee-folk. Whatever it is, they certainly wouldn't be using washboards.
5 Yeah. What if? No pepperoni pizza and soda pop for you, locust-breath. Maybe a cool, refreshing Haworthia is just what you need. This bud's for you. Or maybe that bud is. Or that one. Perhaps with a few bites of leaf on the side.
6 In fact, I would have a hard time taking seriously anything at the linked website, and didn't even read that page once I hit the following quote in the sidebar:
At the core of quantum is co-creativity. We say, "This is Special Me. This is what I am. This is what I want." Quantum reality responds with "Great! Very cool expansion of the Whole you are! Will this help you? How about this? . . . or this? . . . or this??" Quantum reality responds to our assertion of our uniqueness by supplying the goods.I'm assuming, from context, and from the other stuff I saw before I quit reading in exasperation, that this is being quoted approvingly, despite the fact that it makes not a shred of sense. It is pseudoscience of the worst variety, (see an earlier post for a brief digression into the meaning of "pseudoscience") the kind that uses words it clearly doesn't understand to make points which are clearly not true, and is all just more of the same The Secret / Prosperity Gospel / visualization / magical thinking garbage that pops up in a new form every few years to pull money out of a new batch (or, more likely, the exact same batch) of suckers.
When this sort of stuff comes up, I'm frequently reminded of this exchange from "Futurama:"
(Background: MORBO is a bulging-headed alien newscaster who openly refers to himself as a scout for an upcoming alien invasion of Earth. LINDA is his co-anchor, and is basically what you'd imagine Mary Hart of "Entertainment Tonight" would be like after an hour of huffing nitrous oxide. They are discussing a very rapid warmup of the earth which would be way too involved to explain for this one joke.)
MORBO: Direct your pity now to the African turtles, seen here
migrating to cooler homes in Holland. . . . Morbo wishes these stalwart nomads peace amongst the Dutch tulips.
LINDA: I'm sure those windmills will keep them cool!
MORBO [turning towards Linda]: WINDMILLS DO NOT WORK THAT WAY! [turning back to camera] Good night!
Wanting things does not bring them to you. If it did, nobody would ever be disappointed. Visualizing things does not make them happen that way. If it did, nobody would ever be surprised. If you find that you can manipulate the world that way, you should seriously consider the possibility that you are delusional, or that at the very least you have such a strong case of confirmation bias that you fail to see almost everything that happens around you. The ways to make things happen are to practice, research, experiment, rehearse, train, learn, and search. (The exact list will depend on exactly what you're trying to do. I also note for the record that for someone who already has the necessary skills, visualizing may well count as rehearsal, and improve performance. But it's not like visualizing yourself pole-vaulting is going to help you become a pole-vaulter if visualization is the only practice you ever do.) Sitting around on the couch, with pleasant tinkly music playing and a full belly, wishing for things, besides being extremely insulting to the millions of people in the world who are at war, or on the verge of starvation, or terminally ill, or who have just lost loved ones, or whatever, is going to lead to exactly one outcome: the same stuff that would have happened anyway, but without any input from you.
Also, since s/he mentions it on the page I linked to, I am supportive of efforts to collect, test, and disseminate ethnobotanical knowledge, alternative therapies, etc., on two conditions: 1) the people providing the knowledge should receive some of the benefits of it. So, like, a pharmaceutical company shouldn't be allowed to send somebody out into the jungle to ask around for cool medicinal plants, clear the natural habitat in order to take the plants, synthesize the active molecules, patent them, and become filthy rich. Most of the money should be going to the people who made the actual discovery. I don't know, legally, how such a thing could be enforced, but it pretty obviously seems like there should be fair compensation for such things. And by "fair" I mean "a lot." Like, they should be able to afford to buy the drugs that their information provided, at bare minimum. 2) If an alleged treatment is found not to work, in a a) number of b) competently-executed c) double-blind studies which are d) not funded by the proponents or opponents of the treatment, then we shouldn't continue to throw good money after bad in the hopes of getting a result that supporters of the treatment like better. One of the hallmarks of junk science and pseudoscience is their tendency to persist regardless of how many times they are shown to be ineffective or harmful.
Also there's a weird tendency in certain circles to privilege folk beliefs. As if not having formal training on a subject makes you more qualified to talk about it. On this topic, and because I find it scandalous, I would just like to note that abstinence-only sex education in Florida has now led to folk beliefs among some Florida teenagers that, one, either drinking a shot of Mountain Dew after intercourse, or smoking marijuana, will prevent pregnancy; two, drinking a capful of bleach after intercourse will protect against HIV. This is not true just because laypeople believe it. It would also be untrue if it had been passed on from teenager to teenager for thousands of years. (My people perish for lack of knowledge. Hosea 4:6)
But so, returning to the Haworthias and protection from lightning and all that: [clears throat]
LIGHTNING DOES NOT WORK THAT WAY!