If you have any interest in succulents, or have ever tried to grow one on your windowsill, chances are you've come across Haworthias. This genus of small,rosette-forming clustering succulents native to the arid scrub ecosystems of South Africa has become immensely popular in the exotic plant trade - with many species finding themselves under high demand from amateurs and collectors alike. Only one problem - most species in the genus are fairly slow growing. With most Haworthia species, this isnt a problem because they readily produce offsets from the base of the plant - either arising from root-like runners or the lateral buds between leaves - which can be separated from the mother plant and grown on to full-sized specimens. Typically, (though not as a rule) the fleshy species of Haworthia tend to produce offsets more profusely and at a younger stage. Examples of these are H. cymbiformis, H. mirabilis, H. monticola, H. cooperi, and H. turgida among many others.
However, some species are very slow growing and slow to produce offsets, which means they can sometimes be quite time-consuming to propagate vegetatively. Many of the fenestrate Haworthias (the ones bearing thick leaves with a transparent upper epidermis layer, or 'window') fall into this category - such as H. emelyae, H. bayeri, H. mutica, H. mucronata, and H. glauca among others. In such cases, growers use a technique to 'decapitate' the mother plant to encourage the growth of offsets from the lateral buds.
This 'decapitation' method seems a bit complex at first, but never fear - it provides multiple back ups to make sure you don't lose your plant. This is the basic method:
Identify the top 5-6 leaves of the Haworthia and see where the lowest one meets the stem. This is where you want to make your cut. Be patient, this is often the hardest step!
Use a strong, fine thread to loop around the central stem of the succulent at this point. You can use a toothpick or a pair of forceps to pass the string under the leaves, and make sure it sits flush with the stem (see the basic anatomy of a Haworthia in the diagram above - the red line in the magnified box indicates the thread).
Gently but firmly pull the thread from opposite ends to sever the top of the Haworthia, like a garrotte wire. You should end up with a cup-like lower portion, and a detached upper rosette that can be rooted in any well draining medium - ensuring you don't lose your plant.
The base of the mother plant (still rooted in its original container) should produce offsets from near the cut in 4-6 weeks. Once these are large enough to detach, they can be removed, rooted and grown on to maturity.
The images above show the rooted decapitated head (left) and the mother plant after the offsets have developed considerably (right) on a Haworthiopsis glauca (formerly Haworthia glauca) on which I first tried this method. As you can see, the mother plant produced 3 offsets, and the 'head' that I removed and rooted can now even be 'decapitated' again, if I wanted to make even more offsets.
Unlike other methods, this is a fairly invasive method of propagating a plant - and is mostly used only in commercial settings where reducing the propagation timescale is vital. But with a little practice, its fairly easy, despite seeming quite daunting. If you try it out, let me know how it goes in the thread below - I would love to hear from you!