ZEBRA CACTI - HAWORTHIA
Top Tips & Info
- Care Difficulty - Easy
- A few hours of morning or evening sun is mandatory, especially in the winter months
- Be careful when watering - allowing excess moisture to sit in the cubbyholes of the stem will result in diseases like southern blight and 'heart rot'.
- Fertilise every two or three months using either a 'Cactus' or 'Houseplant' labelled feed.
- Repot three years during the spring, using a 'Cactus & Succulent' potting mix. This is the perfect time to propagate the small offshoots that'll form at the base of the crown. Carry on reading to learn more about the top tips mentioned above.
- Haworthia are perfect for a desert-themed terrarium or display due to the slow growth habits and interesting foliar patterns.
Location & Light
Haworthia can withstand all levels of indirect light - ranging from a windowsill to a semi-shaded shelf. Not only this, but this genus can also become acclimated to partial sunlight, too. If you're interested in placing yours in a brighter environment, gradually increase the light levels over the course of a few weeks to prevent the risk of environmental shock or sun-scorch. For those in a shadier area, be sure to keep the specimen on the drier side to avoid the large risk of 'heart rot'.
Water
Allow all of the soil to dry out in between waters, reducing this to once a month in the autumn and winter. One word of advice is never to allow excess moisture to settle either in the actual crown of the plant or underneath the pot, as both will cause southern blight or even black rot. Under-watering symptoms include drooping leaves, stunted growth, and drying leaves; these can be a range of different issues, including forgetfulness, too much sunlight, or the plant being pot-bound. Over-watering symptoms include root rot, a rotting base, or sudden plant death. Haworthia must have sufficient light levels (at least two hours of direct sunlight a day) to counteract the chance of root rot, if you're an avid over-waterer.
Humidity
This is not a factor; however, if the Haworthia is situated indoors, a quick hose down from time to time will reduce the number of dust particles covering its leaves.
Fertilisation
Fertilise every two months during the growing period and every three months in the autumn & winter to replicate its dormancy period. Although a 'Houseplant' fertiliser will still do the job, we'd recommend using a specific 'Cactus' labelled feed as it'll support the vital thirteen nutrients that this species will need to grow.
Common Issues with Haworthia
Over-watering is the most common issue, with typical signs including a softened centre and blackened foliage. There must be periods of droughts to replicate the habitats of the east African deserts, as well as limiting the chance of diseases. Avoid waterlogging as there's no point fulfilling the phrase 'drenches between droughts' if the base of the pot is submerged.
A pale centre and deformed growth are typical signs of too little light. Offer at least an hour of direct sunlight, especially in the winter months, to provide the vital nutrients that'll be converted into plant sugars.
Scorched or browned edges are the result of too little water and over-exposure to the sun. Although Haworthia are a superb choice for plants in sunny locations, those that haven't acclimatised to the harsh rays will show signs of sun-scorch and environmental shock. Prolonged exposure will significantly speed the process of dehydration, so consider transplantation into a bigger pot (in the spring) to wrap the roots around moister soil.
Over-supplementing a Haworthia will bring nothing but grief in the likes of yellowing leaves and weak, dramatic growth. Although regular feeds are an excellent way to promote good health, dry soil and fertiliser salts will quickly lead to the burning of roots. The advice for this issue is to pre-moisten the soil beforehand and reduce the frequency of fertilisations somewhat.
Origins
Haworthia consists of over sixty species, originating from semi-deserted locations in southern Africa. The genus was first described back in the 18th century, but its true taxonomy has been greatly argued over the last century. The movement of species within the genus has been empathised by new research into the polyphyletic construction. Previous subgenera like Haworthiopsis, Tulista and Gasteria have now been placed in their own genera. To save confusion between the genera within the article, 'Haworthia' will act as an umbrella name for all genera and subgenera. The name was penned by Duval in honour of Adrian Hardy Haworth, an English botanist in the 19th century who classified many plants throughout his working life, such as the Orchid Cactus, Fishbone Cactus and the Queen of the Night Succulent.
Temperature
10° - 25°C (50° - 78°F)
H1b (Hardiness Zone 12) - Can be grown outdoors during the summer in a sheltered location with temperatures above 12℃ (54℉), but is fine to remain indoors, too. If you decide to bring this plant outdoors, don't allow it to endure any direct sunlight as it may result in sun-scorch and dehydration. Regularly keep an eye out for pests, especially when re-introducing it back indoors.
Spread
Most species will reach heights of 0.2m in height and 0.4m in width. Ultimate height will be reached within 5 - 8 years.
Pruning & Maintenance
Remove yellow or dying leaves, and plant debris to encourage better-growing conditions. While pruning, always use clean utensils or shears to reduce the chance of bacterial and fungal diseases. Never cut through yellowed tissue as this may cause further damage in the likes of diseases or bacterial infections. Remember to make clean incisions as too-damaged wounds may shock the plant, causing weakened growth and a decline in health.
Propagation
Via Seed, Offset Division or Stem Cuttings.
Offset (Pup) Division (Easy) - For this method, it's best to divide in spring or summer and once the offshoots are at least a quarter of the mother plant's size. Remove its pot and place your hand in between the junction that connects the two; soil may have to be brushed away to get a better grip. Gently push the pup downwards while supporting the mother plant until you hear a snap. Cautiously separate the root systems, keeping great care in keeping them damage-free. Place the new plantlet in a small pot with a well-draining potting mix, much similar to the original soil, and maintain the same care routines. 'Cactus & Succulent' compost is best, or you can make your own using multipurpose compost with added grit or perlite. Provide a bright setting with temperatures around 18°C (64°F) with the majority of the soil drying out in between waters. New leaves should emerge within the six weeks, as long as the soil is kept on the drier to life.
Stem Cuttings (Succulents) (Easy) - Using a clean pair of scissors, cut a 10cm (4 - 5 inches) section off the stem's terminal. Be sure to use a fresh, damage or pest-free piece as unhealthy divisions are more likely to fail. Remove the older half of the leaves, so that the stem's lower portion is bare, to speed the process of root development. Purchase a 'Cactus & Succulent' compost and vertically push the cutting's base into the soil, avoiding the risk of covering the actual foliage with soil. Situate the cutting in a bright, indirect setting with temperatures above 18°C (64°F). As the roots will develop first, remove the bag and treat it as an adult specimen once there are signs of new foliar development.
Flowers
Yellow, red, pink or white flowers are held by a spike thatch reach heights of 30cm per summer. Each flower can last up to several days, with the blooming process lasting several weeks.
Haworthia may flower in the height of summer if its previous dormancy period has been served well. The quality of its blooms largely relies on the quality of the dormancy period served in the previous winter.
To replicate its dormancy period:
- Reduce temperatures down to around 12°C (54°F) from late autumn until early spring, with little hydrations or fertilisation.
- Allow all of the soil to dry out for at a fortnight in between irrigations thoroughly, and never apply cold water as this may damage the roots.
- Provide a few hours of off-peak direct sunlight with one fertilisation throughout this period, until the first bud develops at the end of spring.
Repotting
Repot every three years in the spring, using a 'Cactus & Succulent' labelled potting mix and the next sized pot with adequate drainage. Haworthia are far better potbound for several years due to the heightened risk of root rot and repotting-issues (like transplant shock), so only repot if you feel it's wholly necessary - restricted root growth will also increase the chance of blooms, too.
Hydrate the plant 24hrs before tinkering with the roots to prevent the risk of transplant shock. For those situated in a darker location, introduce an extra amount of perlite and grit into the deeper portion of the pot to downplay over-watering risks.
Pests & Diseases
Keep an eye out for mealybugs, scale, whitefly, vine weevils & root mealybugs that'll locate themselves in the cubbyholes and undersides of the leaves, with the exception of the latter two in the soil. Common diseases associated with Haworthia are root rot, botrytis, rust & southern blight.
Toxicity
This plant is classified as non-poisonous. If large quantities of the plants are eaten, vomiting, nausea and a loss of appetite could occur.