Haworthia is a genus of succulent plants native to the southern parts of Africa. They are usually small rosette forming plants with fleshy leaves that are hard in some species and softer, with translucent window-like tops in others. There is a great variety of plants and hybrids within this genus.
Haworthia are mostly green in colour and grow in shaded or semi-shaded positions (under trees, bushes or rock overhangs) in their natural environment. A lot of the species will withstand full sun if acclimatised, but their shape and colour will change. Just like with the majority of all other succulents, Haworthias respond to sun exposure, water, seasons and weather.
The genus of Haworthia is a large one and has gained popularity among succulent enthusiast for their shapes, leaf patterns and the fact they are quite small growing.
Because they are mostly shade loving plants, Haworthia (unlike most other succulents) will happily live in a bright and airy spot indoors. They are also not fussy, easy to look after and can be kept in cute little pots.
For various reasons, Haworthia may turn from green to brown or reddish colour. This may or may not be bad news (it mostly isn’t). So why do they change?
Haworthia can turn from green to brown colour as a response to stress from the sun, seasons, temperature, water or even pot size.
I will cover each reason that we know of in detail based on my experience of growing these plants in our nursery and determine whether a particular change is a reason for concern or quite natural and what can be done to make them grow green again.
As stated above Haworthia usually grow in shaded spots in their natural environment. The plants grown in our nursery live in a greenhouse with a 30% shade cloth. In summer, however, we double up the shadecloth as the sun during heatwaves of 40C (104F) and over can stress the plants too much and even burn the foliage. As a result all the plants are a pretty shade of green.
If Haworthia are exposed to too much sun, especially on warm days and in the afternoon when the sun is strongest, the leaves can start browning and loosing the green colour. This change is also likely to happen more in summer when the sun is out longer and the intensity of UV is higher.
To stop the browning process, the plants simply need to be moved out of the sun and into shade. There is, however, a bit of light balance that needs to be maintained as when Haworthia are in too dark a spot, they will start stretching in search of light and the growth will not be compact.
The browning caused by sun exposure is not likely to hurt the plants, unless the sun is too strong and causes sunburn, and can be reversed quite easily by a move to the shade.
Seasons & Weather
A large number of succulents respond to changes in the seasons by developing different colours. Some species from the Haworthia genus are also prone to this. The change is usually triggered by dip in temperatures.
The colder it is, the more colourful the succulent. Because Haworthia is a large genus it would be hard to name all the individual plants that can change colour with the seasons. If you see brownish, red or orange colours during autumn/ winter, this is likely due to season change. This can also happen when the temperatures drop during the warm months.
The colour change is quite natural and the colours will revert back to green when winter and cold weather pass. When the plant is moved into a warm environment (greenhouse/ indoors), the browning may not occur.
Haworthia are not frost hardy and, therefore, should not be left outdoors when frost is expected. They will happily live outdoors if the temperature does not dip below 0C (32F).
In our experience Haworthia do not mind water, especially when warm. The sun and lack of water can be a bit of a double whammy and usually speeds up the browning process.
During severe droughts we put Haworthia and other shade lovers into tubs of water. We leave the water to dry out and refill when the potting mix has also dried, but this works a treat for us and prevents the loss of green colour. It is important to point out that our nursery is in Australia and in summer temperatures climb well over 40C (104F) often and rain can be unreliable. I would also not recommend doing this indoors as Haworthia could rot.
In countries with regular rainfall and more stable temperatures, measures like these are not likely to be needed. Watering your plants when the potting mix dries up should be enough. If the plant is browning, up the water and move the plant out of the sun.
Small Pot and Root Bound Plants
In most cases when succulents (and other plants) are re-potted from a small pot where their roots have reached the limit of the pot into a bigger pot, the growth accelerates a bit and plants grow greener.
While Haworthia, if kept well watered and in bright shade usually stay green, being root-bound or kept in a small pot for too long may result in stress induced browning.
This is unlikely to kill succulents. In fact, many succulents are purposefully kept in small pots to intensify their colours. In Haworthia, the colour that intensifies the most is brown or orange and by repotting into a bigger pot, it will turn back to green.
It is always a good idea to re-pot plants every year to check on the health of the roots, mealy bugs (these little pests often attack haworthia roots) and provide new potting mix. In return your Haworthia is likely to grow pretty and green.
Rotting plants can start developing brown and squashy leaves and this is not a good sign. The plants in the Haworthia genus do not often rot from root rot or get brown spots from a fungal disease, but it is not unheard of.
Rot can be triggered by excessive watering, by keeping plants in pots without drainage holes, in very humid environments (bathroom) or if they are exposed to full sun in extreme temperatures (some succulents can literally cook and collapse in a heap of mush).
To prevent this happening Haworthia should be planted in well draining potting mix and pots that have a hole at the bottom, so excess water can drain away. Also do not expose Haworthia to sun when temperatures are forecast to go above 30C (86F).
All in all, Haworthia are fuss free and super cute plants. A bit of browning is likely to occur at some stage, but is usually easy to fix and quite natural.