Droseraceae
Drosera
The sundews — leaves covered in stalked glands, each holding a bead of mucilage that is glue rather than digestive fluid. The tentacles bend inwards onto trapped prey, and in some species, including the Cape sundew grown here, the whole leaf blade rolls over it. The genus spans temperate species that need a hard winter and subtropical ones that do not, which makes "sundew care" a much less useful phrase than it sounds.
Native to Cosmopolitan, with a centre of diversity in Australia and southern Africa
How Drosera generally wants to be treated
Species pages start from this and record only where they differ.
- Light
- Six to eight hours of direct sun. No carnivorous-plant authority publishes a lux figure — one of them declines in as many words — so hours of sun is the honest unit. Under-lit plants stop producing dew, which is the first thing you notice and the easiest to fix.
- Water
- Rainwater, distilled or reverse osmosis, in a permanent tray. ICPS allows tap water measured under 90 ppm total dissolved solids; other carnivorous-plant sources put the safe line nearer 50 ppm. Take the lower figure if you are unsure — the damage is cumulative and invisible until it is not.
- Humidity
- Less critical than the hobby assumes for the subtropical species. Good air movement matters more than a high number, and an enclosed case brings fungal problems.
- Temperature
- 50-95 °F (10-35 °C) suits the Cape sundew across the whole year. An optional winter cooling to 45-55 °F (7-13 °C) gives it a rest but is not required.
- Substrate
- Nutrient-poor: sphagnum peat or live sphagnum, often cut with sharp sand or perlite. Sphagnum is the documented peat-free route for sundews. Coir is not — growers report chunk coir causing long-term decline in this genus specifically, which is worth knowing before making the environmentally sensible-looking swap.
- Fertilizer
- Never in the soil. Foliar feeding is a different matter and is actually documented: ICPS notes that plants over about a centimetre respond to a light misting with dilute high-nitrogen feed, and a published experiment doubled photosynthetic rate, biomass and leaf count in fed Cape sundews. Feed protein rather than chitin — most of the nitrogen in an insect's shell goes unabsorbed.
- Propagation
- Leaf cuttings, root cuttings and seed. The Cape sundew is self-fertile and sets seed freely, to the point of weediness — expect volunteers in every neighbouring pot.
- Dormancy
- Depends entirely on the species, and getting it wrong in either direction is fatal. Temperate sundews need a genuine cold winter. The Cape sundew does not: three carnivorous-plant sources say so positively rather than by silence, and it simply grows more slowly through winter. Do not apply a Venus flytrap's dormancy to one of these.
- Common problems
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- No dew is the first symptom of almost everything — usually too little light, sometimes mineral-laden water, occasionally very dry moving air
- Mineral burn from tap water, cumulative and slow to show
- Dead dry insects often fail to trigger the leaf wrap at all: the response is chemical, and in one experiment only live flies or crushed body fluid produced it
- Fungus gnats and aphids; the plant catches the first for you
- Seedlings everywhere, if you let it flower
- Chilling it like a flytrap. Its relatives need a cold winter; this one does not
In the collection
- Cape sundew Drosera capensis L. 'Alba'