Haworthiopsis viscosa, formerly known as Haworthia viscosa, is a succulent with a distinct trifarious arrangement of the leaves. It grows…
|Family:||Asphodelaceae (as-foh-del-AY-see-ee) (Info)|
|Genus:||Haworthia (ha-WORTH-ee-a) (Info)|
|Species:||viscosa (vis-KOH-suh) (Info)|
Average Water Needs Water regularly do not overwater
USDA Zone 10a: to -1.1 °C (30 °F)
USDA Zone 10b: to 1.7 °C (35 °F)
USDA Zone 11: above 4.5 °C (40 °F)
Where to Grow:
Suitable for growing in containers
Soil pH requirements:
By dividing rhizomes, tubers, corms or bulbs (including offsets)
Allow cut surface to callous over before planting
From seed direct sow after last frost
From seed germinate in vitro in gelatin, agar or other medium
Bag seedheads to capture ripening seed
Allow pods to dry on plant break open to collect seeds
Seed does not store well sow as soon as possible
This plant is said to grow outdoors in the following regions:
Vista, California(9 reports)
On Feb 6, 2015, Kell from (Zone 9b) wrote:
Per Jan Emming owner of the Destination:Forever Ranch and Gardens, a 40 acre desert botanical garden and sustainable living homestead in the Arizona desert with a nursery:
Haworthia viscosa has fascinating columns of stacked leaves in a triangular arrangement when seen in cross-section. When well-watered the leaves turn green, but if a bit drought-stressed they tend to turn a bit more of an ochre tint.
On Jan 27, 2015, poeciliopsis from Phoenix, AZ wrote:
Central Phoenix -- I grow Haworthia viscosa in the ground and my "parent" clump is 20+ years old. It tolerates quite a bit of sun if it's base and roots are shaded. All of mine grow against some surface (Trex border, rock) which seems to provide a better growing condition for this species. Mine receive either every-other-week or once-a-month water in summer and none in winter. The "parent' clump is under a winter cold frame, but the younger clumps are unprotected in winter.
On Sep 13, 2003, Happenstance from Northern California, CA wrote:
Attractive stacked leaves on this Haworthia are its main attraction with insignificant flowers. See this in person to get the full impact of the thin sharply defined and pointed leaves that form stacked spirals. An unusual and interesting form. Greenhouse grown in 9b.
On Nov 27, 2001, tiredwabbit from Point Pleasant Beach, NJ (Zone 7a) wrote:
Most succulents do not need to be watered like you average houseplant. If you water or over water these succulents to much the will most likely wind up with root rot. So be very careful not to let them sit in any excess water and do not water again until dry!
Haworthias- the Jewels of the Succulent World
Haworthias are in the same family as the aloes (Asphodelaceae in Davesgarden, and Aloaceae in some other websites/encyclopedias). These South African succulents look like minature aloes with sturdy, perfect rosettes- they are the jewels of the Asphodelaceae. All are relatively small (and some are really small) and consist of soft and rubbery, to fuzzy, to firm and leather-like succulent leaves. Their size and durability make them ideal for pot culture. The following is an overview of this genus and a description of their care.
(Editor's Note: This article was originally published on February 21, 2008.)
I have a number of these planted in the garden, but that was before I started running out of garden space. Though these are small enough that I can usually still find a spot for them, I lose them sometimes (can’t see them). And now that I appreciate them more, ‘finding a spot’ for them is no longer satisfactory. I want to be able to see them easily and monitor their progress. We are slowly transferring the bulk of our Haworthia collection over to pots, but currently are still concentrating on group pots. So far, only the prize plants end up in solitary pots but that is probably the wave of the future for much of my succulent collection as I get more involved in them (as long as I can find a place to put all these pots).
Haworthia cooperi growing outdoors (not my garden)
Outdoors these plants do fairly well in zones 9b-10b in arid climates, though in zones 9b-10a some may need overhead protection from cold. Most cultivation information on these plants rates them 10a or 10b plants, but I find most are not that marginal and do fine in zone 9b. I have yet to have cold damage on a single species that I know of, and it’s gotten down to 25F in the yard. But few, if any, are sitting out fully exposed to the elements… most have a sparsely leaved trees or a patio roof nearby keeping severe frost from settling on them. And those in the garden almost always have some larger plant partially overhead. They make fairly decent landscape plants filling small areas between rocks nicely. But they often get lost in complicated and overgrown gardens, and then suffer from lack of light. So now I grow most in pots.
I only rediscovered this Haworthia limifolia a few years after I planted it. Nice plant, but hidden by the things above
As potted plants they are mostly fairly easy and forgiving plants (some notable exceptions). They just need well draining soil, a little bit of top dressing and water at the proper times/amounts (this is where I usually screw up with succulents).
There are dozens of ‘recipes’ for succulent soil, and all may work well. Some organic soil is needed (like potting soil) and some material is needed to increase water porosity/draining (sand, small gravel, pumice etc.). Pumice, and to some extent perlite, are great soil additives. It seems one can make a good cactus soil with nearly any type of base as long as enough pumice is added (1/3-1/2 of the total soil volume should be pumice). Sand is good, too, but try to avoid super-fine grain sand, or unwashed sands that might have a lot of salts in them. Some growers add a little charcoal, a bit of shredded bark etc. Experimenting to see what works best in your climate is a good idea (warm climates may require more water-retention properties than cool or indoor climates), though best not to pick an expensive or rare species to start with. I just use ready-made cactus soil from any nursery, and add a bit more pumice to it.
If one looks up photos of Haworthias growing in the wild, one will soon notice many of these species are nearly buried in the soils with only the leaf-tops exposed. They do not need to be planted this way in pots, and look a lot nicer with at least some leaves sticking out above the soils.
Haworthias (and some other plants in this photo) growing in a pot. These have 'naturally' pulled themselves down into the soil a ways. This pot is in full sun so it may have been a protective behavior.
Top dressing is a good idea, not just for looks, but helps to keep the plant’s leaves off the wet soil (decreases the likelihood of rot that way), promotes drainage through the soil (keeps the soil from desiccating completely so that water moves THROUGH the soil, and not right around it, as can happen if one lets the soil go bone dry), and keeps the soil in the pot during careless watering (not a common problem for most, but is for me). Top dressing is also a way of burying part of the leaves ‘safely’ if one wants to replicate the look of these plants in nature. But I rarely put on that much top dressing.
Gravel top dressing improves neatness as well as stabilizes soil
Most plants, if healthy, quickly develop a fairly large root system (relative to the small size of the above-ground plant) and should resist a good tug 1 month after being planted. Plants that pull out easily often have something wrong with them. Check the roots for root, mealy bug etc.. These plants may need to be re-rooted (get rooting hormone) in an evenly warm, well lit but protected environment. Once it’s rooted well, it can go back out into the general collection for more abuse.
Mail order plant (Haworthia cooperi var. leightonii) showing what was healthy roots (now most dead/desicated)- these will regrow quickly once planted
I grow all my Haworthias outdoors in California, but in many parts of the country, year-round growing of these plants will be impossible (not very cold hardy). This makes it easy for me to give my plants sufficient light. Growing in a greenhouse will also provide sufficient light… but grown indoors for much of the year can create etiolated, weakened and abnormally green plants. The more light the better, with the exception of full sun for those species that can’t tolerate it, or are unaccustomed to (can sunburn severely, and subsequently rot). Most of my Haworthias sit in pots in partial day sun (some get full sun) and 90% do well… a few have gotten more sun they obviously like, and I now know not to put those species in hot sun.
Some of these plants showing sun damage 3 weeks after planting
Watering for me varies depending on the pot situation- most are in community pots where it is not always easy to tell if the soil is wet or not. Watering these pots consists of watering frequently when it’s warm and dry (but not at the very peak of the heat- they seem to go through a period of summer dormancy at this time), and less to not at all in winter when it’s cold… however, many pots are sitting under the grey skies of winter storms and get a lot of rainwater at a time when they are probably mostly dormant. And I have to say I have not had a problem from rainwater yet. Cold, yes. Rain water, no.
Individual plants in smaller pots demand a bit less carelessness. Water ideally when soil is getting dry, and not if wet (sounds easy, and really is, but when you have thousands of plants to water, taking time to see if each pot is dry or not takes too much time to me). When in doubt, best to skip watering… too much is worse than too little. Some pots dry out faster than others, too (if glazed, unglazed terracotta, metal, glass, etc.- all dry out at different rates).
I rarely fertilize my plants and perhaps I should do this more. Some experts recommend just repotting every few years and that will pretty much negate the need for fertilizer (as long as new potting soil is used each time- NEVER use used soil… like I do!). Every once in a while I pass my Miracle grow sprayer in the direction of the Haworthias, and that is all they get. So far as I can tell, I have not over-fertilized one, but it reportedly is not hard to do.
Haworthias flower all year round as best I can tell. Their flowers are far from spectacular and all look nearly the same to me. But if one wants to grow Haworthia from seed, one either needs to buy seed, or become a pollinator and start transferring pollen from flower to flower, plant to plant. This is a good way to create all sorts of hybrids. I usually cut flowers off as they tend to detract from the plants themselves and get in the way (sometimes I yank one of the ground or knock a pot over if a flower gets caught in a glove or sleeve).
Flowers from two different Haworthia species (most look the same). Photo on right by Franj
Making more Haworthias- these can be grown from seed, but I have never done that, and see little reason to do so. I know there is a joy and pride in seeing plants grow from sewn seed, and maybe someday in the future if I have more time I will do that. Most Haworthias will eventually offset and those are easy to separate and then one can have more of the same with minimal effort. I use a lot of rooting hormone… anytime roots come out of the soil with an injury, or I cut them on purpose separating an offset, on goes the rooting hormone. If cutting off an offset/pup, best to let it ‘cure’ or callous over a day or so before replanting it again. Leaf cuttings are reportedly not that hard, but I have never done one. Be sure to cut off the leaf with at least some stem (root is not necessary). Put in warm area on slightly moist soil (in summer is best) and keep out of sun. Eventually it should root into the soil.
There is a particularly good web site that is currently the ‘on-line’ bible for Haworthias and is, appropriately, Haworthia.com. I visit this site frequently if I am trying to figure out what something is and maybe how to take care of it. Davesgarden also has an extensive photographic collection of Haworthias. In this article I will cover only a few of the many many species and varieties there are available in cultivation.
I find a lot of Haworthias look alike. Telling them apart can be pretty difficult at times. The following is a short list of some I particularly like and find unique.
Haworthia acuminata in my garden Haworthia angustifolia outdoors in southern California Haworthia arachnoidea (one of several varieties)
Haworthia attenuata outdoor in the landscape, southern California single Haworthia attenuata plant in pot outdoors Haworthia bayeri in cold frame
Haworthia blackburniae var graminifolia (this is about as good as it ever gets- very 'un-Haworthia-like plant) Haworthia bolusii
Haworthia coarctatas in the landscaping
Haworthia cooperi varieties in first two photos Haworthia cooperi var. truncata in last photo (by Mr_Cleaver)
Haworthia 'cuspidatas' in the landscape, southern California. This may not be a true species name. Haworthia cymbiformis, also as a landscape plant in California
Haworthia emelyaes, one of my favorites, in first two photos Haworthia emelyae var. comptoniana in last photo on right. Leaves of this species are very stiff and hardly feel like plant material at all.
Haworthia fasciata (aka Zebra Plant) Haworthia glabrata Haworthia kingiana (one of my favorites)
all are Haworthia koelmaniorums- another of my favorite species. very stiff, leathery-plastic-like warty leaves and great color
Haworthia limifolia normal and variegated- this is one of the most ornamental species (photo on left by kniphofia) Haworthia longiana, one of the less 'Haworthia-like' species and one of the largest (gets up to 6" tall)
Haworthia magnifica Haworthia magnifica var. splendens Haworthia marumiana outdoors
Haworthia mutica Haworthia nigra
Haworthia parksiana in two photos on left- one of the smallest species (mature rosettes about 1" diameter) Haworthia pumila, another large species
Haworthia reinwardtia Haworthia resendeana
Haworthia retusa in pot Haworthia retusa 'Carl Grove' (this is a much larger rosette) Haworthia retusa in multigeneric community pot growing great
Haworthia truncata, one of the best potted succulents! Haworthia truncata 'Whirlpool' Haworthia truncata var maughani
Haworthia venosa var. tessellata in first two photos (a very hardy species for me) Haworthia viscosa
Spectacular Haworthias: Haworthia cymbiformis variegated Haworthia retusa X splendens Haworthia limifolia 'super variegated'
Haworthia koelmaniorum stress colors Haworthia truncata with variegated off set Haworthia 'Zogonoto'
Many growers of this plant find that growing one to look perfect is not that difficult. And many subsequently show them in competitions and shows in their local areas. Since most of the plants look good, sometimes the challenge is then to create a scene that looks even better to show off each plant. Most don’t bother with this and just put the plant in an appropriate sized and elegant pot with clean top dressing, and hope the plant itself steals the show. Plants usually look best in pots that are on the smaller size so the plant appears to be growing out of its container. A small plant in a big pot usually looks peculiar and rarely wins. Not to mention large pots with smaller plants are not good for the roots in general. Sadly there are few shows that have group Haworthia categories, or I would be tempted to haul my pots down to one.
Variegated Haworthia in a staged set up Old wonderfully 'full' pots in the Huntington collection small Haworthia 'Korizato' that is in such a small pot it's not even visible from above
As I have mentioned already, I really like growing these in community pots- they are excellent 'companions' for each other and other small succulents. The following are a few of the pots we have put together (have to give girlfriend credit for most of these). It takes a few years for plants to offset and really fill a pot nicely, and most of these are fairly new plantings.
3 views of the same pot designed sort of like a Ying and Yang, where one has to move around the whole pot to see it all- this pot has over 24 species/varieties of Haworthia in it
2 more idea pots. The one in the middle is cross-generic (another genus, Gasteria) complicates the picture pot on right shows Haworthis growing in and around sandstone rock with holes drilled in it
Where to get Haworthias:
These are pretty common plants in cultivation, though many species are very rare or impossible to find. But I have yet to visit Home Depot, OSH, Target or Lowes and not seen at least 3-4 species of Haworthia for sale for just $1-$2 each. These are usually the hardier, easier plants, too, and can handle a lot more abuse in terms of overwatering, rough handling and cold exposure. But if you have obtained the 5-7 species available at garden outlet centers, you might try cactus and succulent sales, specialty nurseries, or go on line (there are many good on line sources in the Garden Watchdog section of Davesgarden).
a whole platter-ful of Haworthia koelmaniorum's for sale at specialty nursery Haworthia scabra var starkiana mail order