By Peter Bangayan
(Succulentophile is giving way this week to this article by cactus and succulent enthusiast Peter Bangayan.)
The genus Haworthia and its close relative Gasteria consist of small- to medium-sized succulent plants that are very ideal for a collector with limited space. Endemic to South Africa, these plants are ideal for a windowsill collection because of their tolerance for lower light levels than most cacti and succulents. Haworthias come in many forms, from the hard-leafed window types such as Haworthia truncata, H. maughanii, H. magnifica, H. retusa or H. emelyae to columnar forms such as Haworthia coarctata, H. viscosa or H. reinwardtii, to grass-like soft-leafed plants such as Haworthia blackburniae H. graminifolia or H. wittenbergensis. Gasterias usually have strap-shaped leathery leaves which are two-ranked or in a rosette, and the leaves may be rough and tuberculate or smooth.
Many species of Haworthias and Gasterias are easy to grow. A bright place under the eaves of a house or a windowsill that gets an hour or two of morning or late afternoon sun is an ideal place to grow these plants. If the plants get too much sunlight they usually turn brownish red and cease to grow; on the other hand, if they do not get enough sunlight they become soft-bodied, etiolated and become prone to pest and disease.
Haworthias and Gasterias can thrive in many different kinds of medium. They can be grown in your regular cactus mix of one-third garden loam, one-third well-rotted compost and one-third sharp sand or a coco coir mixture of one-half coco coir and one-half sharp sand or even in pure leaf mold, which is the medium often used by the Baguio and Benguet growers.
The key characteristics that you should look for in a good medium are: it should provide good mechanical support for the plant, it should drain fast when watered and it should contain and hold enough nutrients for the plants to absorb. Many factors should be taken into consideration to determine how often to water the plants. Some of the important things to consider are the type of container used, the kind of growing media and the microclimate of the area where the plants are grown. Many types of plant containers can be used but one must consider that a clay pot will dry out faster than a plastic or glazed ceramic one, and a smaller container will dry out faster than a larger one, a taller container with more media will dry out longer than a shallow one. As for the medium, the more porous (more air pockets) the faster it dries out and some components such as coco coir will retain more water than garden loam.
Microclimate is one of the most important factors in growing the plants, and this will usually depend on the prevailing weather and area where the plants are being grown. Plants usually take up more water during active growing season when the climate is warmer and the media will usually dry out much faster during summer than during the wet season. The rule of thumb in watering Haworthias and Gasterias, and most succulents for that matter, is to wait for the medium to almost dry out before watering again although most Gasterias can tolerate much more watering. Take note also that certain media such as coco coir and pure leaf mold become very hard to rewet once they become bone dry and this can lead to dead roots and plants. Plants should be protected from continuous rains as this will most certainly lead to plant rot.
Newly potted plants usually do not need to be fed but as the organic matter in the medium decomposes and nutrients become depleted, plants can be fed with a dilute liquid fertilizer or a slow-release fertilizer. A fertilizer with a high potassium and phosphorous content and the necessary trace elements is recommended.
One of the most annoying pests experienced by cacti and succulent growers is the scale, a tiny insect that comes in many different forms. One thing they have in common is a protective waxy scale that covers and protects their soft bodies from the environment. Scale insects are sucking insects and they feed on the plants by clinging to the plant parts and suck on the plant juices. A very heavy infestation of scale will eventually weaken, disfigure and kill plants.
Another common pest that attacks succulents is the mealy bug. These soft-bodied sucking insects are easier to control due to the lack of protective shell of the scale. Any proprietary contact or systemic insecticide can control scale and mealy bug infestations and safety instructions must be followed when dealing with these poisonous chemicals. There are also much safer insecticide formulas such as insecticidal soaps or oil and detergent based contact insecticide that kills the insects by suffocating them.
One of the most common diseases that attack succulents are the fungal and bacterial rot. Roots or lower or upper stems of plants infected with rot should be cut clean and fungicide or sulphur flowers applied to the cut portion of the uninfected part. The clean part of the plant should then be allowed to dry in a bright place with good air circulation until it forms a callus. The plant part can then be rooted. Diseases such as fungal or bacterial rot can be prevented by situating plants in an area where there is very good air circulation and low humidity.
There are many Haworthias and Gasterias that one can collect. The more commonly available plants are the ones that offset profusely, plants such as Haworthia turgida, H. cymbiformis, some forms of Haworthia retusa, H. limifolia, H. cooperi, Gasteria bicolor, G. nitida v. armstrongii, G. glomerata and others are readily available and can grow into beautiful clumps in time. The rarer, solitary species and varieties such as Haworthia emelyae, H. comptoniana, H. koelmaniorum, H. springbokvlakensis are much harder to come by. Collecting these small gems of the succulent world can be very satisfying and interesting because of the wide range of forms and varieties. In Japan, some collectors even collect only forms of Haworthia truncata and H. maughanii, while some collect only variegated forms of Haworthia or Gasteria.
As a last note, different authors of Haworthia books usually have different names for the same plant so the beginner collector might become confused initially but a little research and consultation with more experienced collectors should clarify matters considerably.
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On May 2 to May 4 there will be a sale of many interesting cacti and succulents, including Haworthias and Gasterias at the Orchid House at Purificacion’s inside the Manila Seedling Bank Foundation compound, EDSA corner Quezon Avenue, Quezon City.
E-mail the author at succulentophile@yahoo.com.