Botany Cactus and succulents

How to Differentiate Haworthias and Gasterias?

The interest in succulents often begins with the purchase of a few “too cute” little plants simply identified as “assorted succulents”. Then, over time, you discover new words: Aloe, Agave, Echeveria, Haworthia, Gasteria and many others! That’s when you spend hours on the Internet trying to correctly identify (in Latin, please!) our too cute little plants. At this point, of course, there’s no going back. Here you are, engulfed in a spiral, for the sake of the new passion. Let’s jump head first into the bottomless well of knowledge: that of succulent plants (for this week!).

Among all these new species, there are two which look alike, sometimes mistakenly: the haworthias (Haworthia spp.) and gasterias (Gasteria spp.). Here are some tips to tell them apart.

Haworthia? Gasteria? Image: Susan Jang on Unsplash.

Similarities Between Haworthia and Gasteria

A thorough study of these two genera reveals to us that botanists are not even close to settling the issues concerning classification and identification of the Haworthia and Gasteria genera! And that’s the first thing they have in common: lack of clarity! (See the “gray area” section for more confusion!)

All joking aside, there are indeed similarities that can be highlighted. First, these two plants are native to Africa, southern Africa, to be precise. Both are found in South Africa, Mozambique, Namibia and Eswatini. They grow naturally in mountainous places, savannas or fynbos. They have a preference for semi-arid environments. It’s not uncommon to find them side by side.

They also both belong to the Asphodelaceae (formerly Liliaceae) botanical family where they’re found in the company of aloes (Aloe spp.) and daylilies (Hemerocallis spp.). This means that the flowers have 6 identical tepals. According to Plants of the World Online, there are 59 different species of Haworthia and 26 species of Gasteria.

Finally, haworthias and gasterias are both small acaulescent plants (without visible stem) with fleshy foliage and often decked out with marks, streaks or bumps.

Big Differences Between Haworthia and Gasteria

And now the fun part, which will bring its share of exceptions, hence the gray zone section which follows. We must speak here in generalities, because there are exceptions in everything!

Typical haworthias, or should I say, what are called typical haworthias, have dark green leaves arranged in a rosette. These are fleshy and end in a pointed tip (but not as pungent as that of agaves). In general, the leaves are streaked or spotted with white and sometimes these streaks look like limestone deposits, which gives a particular texture to the leaves. To the touch, they feel leathery.

Typical portrait of what we call Haworthia. Image: Elliot Cullen on Unsplash.

As for the typical gasterias, its thick leaves are usually flattened and arranged in two opposite rows, as if the leaves were mainly oriented north and south. Some say the leaves of gasterias are tongue-shaped. The tips of the leaves are often rounded and have the same streaks, spots, or growths found on hawortias.

Gasteria carinata var. verrucosa, with its leaves arranged in two rows. Image: Abu Shawka on Wikimedia Commons.

Haworthia and Gasteria are most easily differentiated by flowering. Unfortunately, this is uncommon in cultivated plants. In haworthias, the flowers look like small white stars with 6 petals and there are sometimes greenish or pale pink streaks. They are grouped in clusters, on a long flower stem. Also arranged in elongated clusters, the flowers of the gasterias are generally orange-pink at the base and greenish at their tip and they have a very characteristic bulge. It’s also because the flower looks like a stomach that the gasterias bear this name!

Images of Haworthia cymbiformis and Gasteria carinata: Wikimedia Commons. Layout: Julie Boudreau on Canva.

The Incredible Gray Zone

Then everything falls apart! First, the famous typical Haworthia is not a real Haworthia! It is a Haworthiopsis. All haworthias with wrinkles have been renamed. Thus, Haworthia attenuata, H. coarctata, H. fasciata, H. limifolia and H. nigra, which are commonly grown ornamental species, are now gathered in the genus Haworthiopsis.

Haworthia cooperi, a real Haworthia! Image: Abu Shakwa on Wikimedia Commons.

The true genus Haworthia now includes mostly species with translucent leaves. It’s like seeing the water inside the leaf. It also has some unique species, such as Haworthia truncaca, which could be confused with a Gasteria, as the leaves are arranged in two planes.

Gasteria? No! This is Haworthia truncata. Image: H. Zell on Wikimedia Commons.

On the other side, some gasterias have leaves arranged in a rosette, as would those of haworthias. This is the case of G. polita, G. pulchra or G. ellaphiae.

Then, if there is a plant that has been named, renamed, renamed and otherwise renamed, it’s a Haworthia or a Gasteria. Historically, up to 150 species of Haworthia have been counted, a number that has faded in the sun due to unrecognized species and displacement of some in the genera Tulista and Hawarthiopsis, as mentioned earlier. It’s worse in the Gasteria, as several species grow close to each other, which has greatly facilitated interbreeding. These numerous variants and these interspecific hybrids give many headaches to the classifiers.

The waltz of name changes is far from over! For example, Tulista pumila var. pumila, better known as Haworthia margaritifera, has 29 registered synonyms, including five different genus names!

And finally, haworthias, gasterias and aloes, being genetically very close, can interbreed with each other. This gives x Gasteraloe (Gasteria and Aloe) and x Gasterhaworthia (Gasteria and Haworthia). Therefore, it’s not always easy to distinguish between these two species. When you have a typical specimen, it’s relatively easy to distinguish the arrangement of the leaves in a rosette or on two planes, but there is always a little rascal to make us doubt our knowledge. Stay alert and beware! Your Haworthia may not be what it seems!

Off you go! Back into the spiral of the bottomless pit!

Julie Boudreau is a horticulturist who trained at the Institut de technologie agroalimentaire in Saint-Hyacinthe, Québec. She’s been working with plants for more than 25 years. She has published many gardening books and hosted various radio and television shows. She now teaches horticulture at the Centre de formation horticole of Laval. A great gardening enthusiast, she’s devoted to promoting gardening, garden design, botany and ecology in every form. Born a fan of organic gardening, she’s curious and cultivates a passion for all that can be eaten. Julie Boudreau is “epicurious” and also fascinated by Latin names.

2 comments on “How to Differentiate Haworthias and Gasterias?

  1. Drives me crazy when garden centers order and carry plants from suppliers that do not have names. Everything else does. Can’t be too hard even when botanists keep changing things up and reclassifying plants. I have several species of Haworthia and a few Gasteria. Side by side they are fairly easy to tell apart. Mine actually flower routinely indoors after having spent the summer outside which also helps. It can sometimes be more difficult to tell the difference between some dwarf Aloes and some types of Haworthia.

  2. Jt Michaels

    Perfect timing, Ms. Boudreau! Although I live in cold north, I am visiting my daughter in southern Arizona where some of these plants are used in landscaping. I’ve had fun trying to figure what is what and you just helped me!

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