The plant, which bears the rather harmless-sounding name sundew, botanically Drosera, comes from the sundew family and belongs to the carnivorous plants (carnivores). The name is derived from Greek usage and is translated as “Tau”. It uses one of the five possible traps and thus differs from the Venus flytrap, for example. The sundew has radiating tentacles with a drop of sticky liquid at the tip. Unfortunately, insects that mistake this drop for a dewdrop have to admit that they were wrong, because touching it means certain death.
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Where does the sundew come from?
The sundew is originally native to Australia, South America and South Africa. However, there is not only the sundew, but almost 200 different species that count. They can now be found around the world, but only a manageable number of variations are kept as ornamental plants. Many of them are endangered in the wild by humans.
characteristics of the plant
Most specimens of sundew are perennial plants that grow either upright or climbing. Depending on the variety, they can reach heights of one to one hundred centimetres, but specimens with a length of more than 3 meters have also been reported. This is the case, for example, with Drosera erythrogyne, which can also live for more than 50 years.
There are these growth forms of the sundew:
- Temperate forms such as Drosera rotundifolia
- Subtropical Formen
- Zwergdrosera, like Drosera callistos
- tuberous Drosera, such as Drosera auriculata
- The rare Queenslanddrosera, which occurs in three species only in the rain forests of the northern Australian state of Queensland
The types of sundew that are most common in European areas are the temperate forms. During the winter break, they withdraw into a hibernation bud and sprout again in spring (hemicryptophyte). They should be kept outdoors in a bog bed, indoors they will not find the right living conditions.
Among the subtropical species there are many different varieties, but also easy to keep and therefore also suitable for beginners, such as Drosera aliciae or Drosera capensis. These species come from a warm region and therefore want to live in a warm room or in front of a sunny window. However, the correct humidity must be observed (50-70%).
Most sundew species have weak roots. They only serve to absorb water from the soil and give the plant support in the soil. As with other carnivorous plants, the roots have almost no importance for nutrient uptake. Nutrients are obtained through the roots only in a few species in South Africa and in some Australian species tuber stores have been established for this purpose.
Different forms of sundew leaves
While the system of the sundew, the hunting of insects, is the same for all variations, the different specimens have different leaf shapes and leaf colors. These ensure that a colorful variety can be put together. The leaves can be either with or without a stalk. In this context, the Drosera binata looks exceptional, which is not only the only one from the Phycopsis section, but above all looks very tousled. It has many thin leaves that split at the tip like the antennae of crustaceans. Some specimens are light-colored, others coloured, while the round-leaved sundew Drosera rotundifolia is round.
The various tentacles of the sundew plant
The tentacles, i.e. the tentacles of the sundew, all work according to the same basic principle, but they look very different. They sit on the leaves and are covered with a sticky secretion and can therefore also be referred to as a stalked gland. All varieties of the plant can move their leaves, the Drosera capensis even by 180°. This allows her to almost completely enclose her prey that has literally been taken in by the trap. The victim’s defense reaction stimulates additional glands to produce the secretion. This strengthens the adhesion to it and at the same time the digestion. If the victims don’t suffocate, they die from exhaustion from the struggle.
Interesting: The secretion consists of the enzymes esterase, peroxidase, phosphatase and protease.
The enzymes contained in the secretion slowly break down the prey and dissolve the nutrients it contains. These are absorbed by the glands on the leaf surface and utilized by the plant. These glands are missing in some varieties, for example in Drosera erythrorhiza. It has been possible to find some specimens that even have quick tentacles. These catch the prey in seconds and similar to the tongue of an insectivorous animal. They bend it towards the leaf blade and attach the captured animal to it, where it is then digested by the enzymes. The quick tentacles themselves have no sticky drops and no enzymes either.
The ideal location for the sundew is a warm place with sunshine, whether on a south-facing window or, with appropriate acclimatization, also in the free-range. In this case, temperatures between 5° and 15° do not bother the plant either, so it does not always have to be brought in when it gets cooler.
Sun exposure is important for the tentacles to turn red. As a result, insects fly at them because they mistake them for flowers.
humidity and watering behaviour
A good location for a sundew is a terrarium, where the ideal conditions for healthy growth prevail if handled correctly. The humidity here should be 50% to 70%. Proper humidity is important for the glue to form on the tentacles.
There should be 1-2 cm of water in this trivet and this amount must first be absorbed before it is refilled. In between, it is essential to take a break until the soil has dried a little.
Tap water is by no means used for this, but rainwater or, alternatively, distilled water mixed with 10% tap water. As a result, the otherwise nutrient-poor distilled water gets the required amount of minerals again, but remains low in lime.
The sundew is not fertilized, it is undemanding in this respect, which is due to its origin. In the wild, it grows on poor soil, and it also gets the nutrients it needs from food.
The right substrate for carnivores
The soil for the sundew and for carnivores in general should have very specific properties in order to enable the best possible husbandry. That is, the main component of the soil should be white peat, which consists of decomposed peat moss, natural and air-permeable. It stores the water for a long time, but it should definitely be watered well before the plant is planted for the first time. Depending on the plant species, it should also be enriched with other components:
- Quartz sand for loosening
- Volcanic rock called Perlite, it stores water
- Vermiculite, a mineral rock that stimulates plant growth
- Quartz gravel is available in different grain sizes and is used to loosen up
- Pine bark, black peat, shell limestone or coconut fibers for mixing
There is also ready-made carnivore soil to buy, which should be used especially if the plants need to be repotted. This substrate can be bought in specialist shops or in a corresponding online shop.
Carnivores like the sundew are very undemanding plants that can get along in modest conditions in nature. Since the soil on which they grow is very poor in nutrients, they need an additional supply in the form of living insects. If these get caught in the sticky traps, they are digested and the plant feeds on them. They stand on the windowsill in a special substrate that offers them the nutrients, so feeding them is not absolutely necessary. If done for the fun of watching, it should only be done with live insects. Dead insects can trigger a mold infestation.
diseases of the sundew
The sundew can also be attacked by biting or sucking insects. These can be aphids, mites and other animals, incorrect watering or condensation can cause mold, which also affects the sundew.
The right environment is the best protection to protect the plant from pests. Here, of course, one has to differentiate whether the Drosera is outdoors or on a sunny window sill. The plants standing in the open air can be attacked and literally eaten by slugs in particular. But birds that scratch in the ground or want to pick out the trapped insects from the Drosera can damage the plant. Birds can be kept away with a fine wire, and there are different means for snails.
Plants that are on the windowsill can be attacked by aphids, scale insects or spider mites. These can damage the plant so badly that it withers or even dies off completely.
Tips Before Buying
Anyone who enjoys cultivating carnivores, and in this case a Drosera, should start by buying a low-maintenance strain that is also suitable for a novice grower. Of course, the word beginner should not sound pejorative in this context. It only serves to assess the degree of difficulty of keeping and the ease of care of the plant. If you consider that there are varieties that are only available in a special trade and that can only be cultivated by a professional with care, it is certainly understandable that this is pointed out.
Even if the plants, such as the often available Drosera capensis, are not very expensive, it would be a shame if they died immediately due to incorrect care. Anyone who wants to buy high-quality plants and prefers a specialist shop should make sure that they can also be complained about and exchanged.
The plants offered in hardware stores or discounters are not always in the best condition, but they usually recover quickly if they are offered the desired conditions.
Depending on which variety you choose, keeping is easy to difficult. Beginners should choose the Drosera capensis, which is known for its frugal attitude. But even she needs a few basic conditions to thrive. If you like this type of plant and have experience in caring for it over time, there will certainly be many more and different specimens.