Speculation on the history of carnivorous plants still exists, but with little fossilised evidence. With advanced molecular science technology, researchers are now able to pinpoint DNA mutations. Where enzymes were previously used in defence of predators, these plants adapted and transformed these enzymes into killing machines.
First documented and named by Carl Linnaeus for its dewy appearance in 1753, Drosera was rediscovered by Charles Darwin in 1860. Darwin studied these plants extensively for over 16 years. He was the first to confirm that the genus Drosera was carnivorous.
Found on every continent except Antarctica, these preying plants secrete sweet nectar from their leaves. They form glossy droplets at the end of sensitive hairs to lure insects. The leaves consist of two separate components. Glands that produce the sticky sweet nectar, trapping and dissolving the insect, and glands to absorb the nutrients through the leaves and into the plant.
Drosera in South Africa
One of the largest genera of carnivorous plants, there are more than 194 species of Drosera. Over 20 are endemic to South Africa. Found in stretches from the Western Cape to the Eastern Cape regions is Drosera aliciae. Also commonly known as the Alice sundew, this species has flat paddle-like leaves, resembling a tongue, adorned with hundreds of sticky red hairs, ready to capture prey. Natural habitats include boggy areas as well as riverbanks.
Another South African favourite is Drosera capensis, the Cape sundew. Due to its easy cultivation and being one of the most common sundews grown for the commercial market abroad, this plant has unfortunately been put on some countries invasive lists. Unlike the Alice sundew, the Cape sundew has strap-like leaves, covered in bright green tentacles that lure prey. Once an insect has been trapped by the sticky mucus, the leaves curl towards the plant leaving no escape for the imprisoned. Digestion can take up to 6 hours. Once all the nutrients are taken up by the plant, the leaf will unfurl to its original state.
These perennials flower in the summer months. Flowering stalks reaching up to 30cm in height, with more than 20 dainty flowers on one stalk flowering in succession. The flowers contain both male and female reproductive organs and can thus self-pollinate. In plant biology this is known as a perfect or complete flower.
Sundews have few requirements, but none of them should be neglected as this could be detrimental to the plant. They inhabit areas that have a moderate climate with temperatures not varying too drastically during the seasons. In their natural habitat, they have high water requirements and have periods of direct sun. So how does this translate into our gardens?
Growing sundews at home
Sundews need soil that can hold moisture for long periods of time. Being carnivorous and having adapted to digest nutrients through their leaves, the potting substrate should be a neutral pH, with no added fertilisers or soil conditioners. Most sundews will do well in a soil mix of 1-part sand to 1-part perlite to 1-part processed sphagnum moss.
Containers and water
Only plastic pots or glazed ceramic pots should be used to house your sundews. Terracotta pots can leach salts into the soil, causing the demise of your plant. Plastic pots also have a better moisture retention and minimises evaporation. Use a plastic pot tray underneath your pot, always filled with water. Do not water your plants from the top. The quality of water used will ultimately determine your success in caring for your sundew. By no means should tap water be used, or even mineral bottled water. The micro-element of minerals will damage your plant and recovery from this is near impossible. Only use distilled water or rainwater.
The next factor is light. This genus of plants does need direct sunlight. A maximum of 4 hours is sufficient. Morning sun is best – with indirect bright light for the rest of the day. Midday sun can be harsh, especially in our summers. It can cause the leaves to burn – which restricts the production of sticky dew. This makes the plant inefficient at capturing prey and digesting nutrients.
For a large range of carnivorous plants, visit Jozi Carnivores
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