Winter is the season that baffles many a gardener. When should you stop or reduce watering? Why are your plants getting spots, turning yellow, drooping, wrinkling, throwing off leaves? These are all problems that originate from a lack of information. Or more accurately, our inability to translate what we read online to our own garden.
In its article, I'll shed light on what rainfall, elevation and dormancy mean for you at home, give you a guideline for the succulent regions, and explain how to implement this with a known troublesome group of succulents: Lithops
or Living Stones.
Winter growers will use this time to bulk up for flower displays later in the year, while summer growers might be pushing flowers or going dormant.
What changes in winter
This seems like an obvious topic, but it is not the case. Changes in winter are vastly different throughout the country. You might know your succulent comes from the Baviaanskloof, but that does not help you know how to care for it. I want to explain how to get more out of your information so you do not stumble when it comes to winter care.
What to look out for:
Rainy season: Does your succulent come from a summer rainfall or winter rainfall area? The Western Cape and West Coast of the Northern Cape is a winter rainfall area. The rest of the country is summer rainfall.
Translate annual rainfall: 1mm of rain is equal to 100ml / 10cm2. 100mm of annual rainfall means a tiny pot of 10 x 10 cm will get 10L of water per year with more during the rainy season. *Note your soil mix and environment will drastically affect this. Some succulents grow between rocks with minimum soil or in the sand. Standard potting soil will require less watering as it will hold onto water.
To test your soil mix see the article below:
- High elevation: Succulents that grow at higher elevations will be exposed to cooler temperatures and less moisture overall. Moisture will only be higher than the surroundings during diurnal or seasonal cycles (nighttime or rainy seasons).
- Your plant will lose leaves or simply stop growing. If you keep watering when the plant is not using it, you will cause leaves to burst or stems to rot.
For a guide on plant dormancy see:
A succulent native to a summer rainfall area, growing at 2000m elevation, will be used to colder, drier winters. Knowing this in advance will help you group your succulents according to their needs. It is easy once you know where they come from.
South African Succulent regions
Now that we know how to read the information, we can go ahead and break down the areas where South African succulents grow.
Elevation: Two zones 550-900m and 900-1300m.
Temperature fluctuations: less or equal to 25C between day and night.
Winter temperature: less than 0C minimum.
Rainfall peaks: March and September
Average rainfall: 100-500 mm
Elevation: approximately 800-1500mwith the highest peaks more than 2000m.
Annual rainfall: ~350mm
Winter temperature: ~5C minimum with scattered frost
Characteristics: High winter humidity, quartz reflects light and has a cooling effect in summer when temperatures stay in the high 30C. They also average out nighttime temperatures.
Soil: Varied, including quartz veld and Enon Conglomerate
Rainfall: 69% during October to March, 31% during winter annual rainfall (292mm), humidity range 20-80%
Temperature: ~30C max and ~3-5C min. Min recorded 3.4C, frost occurring.
Soil: Sandstone, ranging in pH from slightly acidic-alkaline, low organic matter.
Noted species: Mesembryanthemaceae (vygie family)
Rainfall: 400-2000mm in summer, cold winters with frost.
Temperatures: Winter minimum is regularly less than 0C
Soil: Rich, clay
*Disclaimer: Plants can adapt to slightly higher or lower light and water. The idea is to take this as a reference and not flood a plant that cannot handle it.
An example of winter care
The most common winter care advice is:
- Move succulents indoors,
- keep them in a sunny location, and
- decrease watering.
It is great advice but unfortunately does not apply to all succulents. Take lithops or living stones as an example. There are 37 species that grow in both winter and summer rainfall areas.
grows in the highveld with a staggering 800mm of rainfall in summer (less water in winter).
Overwatering lithops is the number one problem plaguing owners. This applies to most succulents, but no water can have equally devastating results. If you are finding your feet in terms of watering and think you might be getting it wrong, look out for the following signs.
Signs of problems:
Yellowing/browning: from the bottom of the stem is a sign of rot.
Wrinkling: Dehydrated succulent either because of too little water, dying roots or sucking insects. (Scale mealybug).
Damaged leaves: Hail or snail damage. Burst leaves or splits are a sign of too much water in a short amount of time.
Wilting or blackening: Frost will cause cells to rupture making the succulent look like it's melting. Frost damage can also turn an area dark black.
Spotting a problem is as important as good care. You learn a bit more with every problem you recognize and plant you lose. The take-home message is that: "adequate watering can solve most problems".
If there is a particular succulent you struggle with make sure to add it in the comments below.
Cowling, R.M. 1986. A description of the Karoo Biome Project. South African National Scientific Programmes Report No. 122.
Schmiedel, U., & Jürgens, N. (2004). Habitat Ecology of Southern African Quartz Fields: Studies on the Thermal Properties near the Ground. Plant Ecology,__170(2), 153-166.
Udvardy, M.D.F. A classification of the biogeographical provinces of the world. IUCN Occasional Paper No. 18 (International Union of Conservation of Nature and Natural Resources, Morges, Switzerland, 1975).