02 Sep HOW TO GROW Sundews?
It is often said that the world is beautiful because it is varied, a phrase that fits perfectly when we ask: but how do we grow Drosera?
The genus we will discuss in this article is composed of extraordinary plants that have colonized every corner of our planet. We know how continents so far apart can present equally distant and different environments: well, Drosera has evolved in this diversity, adapting perfectly to extreme conditions and finding the right balance even where conditions seemed prohibitive.
Premise necessary to understand why, with this genus of carnivorous plants, it is not possible to generalize: there are temperate sundews, sub-tropical and tropical sundews, petiolate sundews and tuberous sundews. And each of them needs different care.
In this article we will look at the various existing types and the different habitats of these beautiful carnivorous plants
Let’s start
Drosera is a carnivorous plant equipped with adhesive traps and belonging, like Dionaea muscipula, to the family Droseraceae. The numerous species belonging to the Genus Drosera are mostly distributed in tropical or sub-tropical environments such as Africa, Australia,South America and although in much smaller numbers also in temperate environments of Europe, Asia and North America.
The fascinating capture mechanism has the appearance of leaves covered with numerous “tentacles” at the top of which are sticky droplets composed of water and polysaccharides. These plants take advantage of the light reflections produced by the passage of sunlight through these droplets to attract the insects, which eventually become trapped in this thick, viscous cocktail of water and sugary substances. Other glands then, called sessile glands, smaller and less conspicuous than the previous ones, produce digestive enzymes that “digest” the insect’s soft tissues.
Often to maximize the benefits it can derive from its prey, Drosera slowly curls the leaves by enveloping the insect with a larger surface area of leaf blade (and thus more digestive glands): in this way there is more production the enzymes and consequently more nutrition. This can take the plant hours or days to do, depending on the species.
At the end of this brief presentation it becomes incumbent upon us to diversify the various types of Drosera to help the reader in recognizing them and then taking the best care of them. Lastly, we will discuss some tricks of the trade and some diseases that can affect this genus in general.
Temperate Drosera
Temperate sundews are a group of carnivorous plants that have evolved to adapt perfectly to acidic bogs where sphagnum proliferates: the pH is very acidic and the presence of nitrogen is practically zero, a harsh environment where there is almost a total absence of nutrients in the soil. Usually these bogs are located in mountainous environments in the northern hemisphere in countries characterized by hot summers and very cold winters.
To adapt to this seasonal climate change they have developed a special form of defense, in fact Drosera vegetates in the warm time of the year where it grows quickly and flowers throughout the vegetative phase. In winter, however, it enters a phase called “vegetative rest” where it completely loses its leaves and flowers and forms a spherical hibernaculum. It is very resistant to the weather: in fact, it is not uncommon for their environment to be totally covered by snow and ice during the winter months.
Vegetative rest is an obligatory and absolutely necessary condition for the life cycle of this Sundew!
A. SUN EXPOSURE
Temperate sundews love the sun! So they should be placed outside all year round in full sun, taking care to shade them during the middle hours of the summer months to avoid the high temperatures of the plains to which they are not accustomed.
Why in full sun?
As with Dionaea muscipula, it is also an energy issue for Drosera; being plants that vegetate only a few months of the year, they need a considerable amount of energy, provided indirectly by photosynthesis, in order to grow fast and produce large amounts of the viscous substance essential for catching prey. Thus greater light intensity results in more vigorous growth.
In addition, this carnivorous plant takes advantage of light rays and the reflections they produce on glue droplets to attract insects! However, it is good to shelter them from the wind: a windy environment will cause the droplets to dry out excessively, reducing the trapping efficiency and aesthetic performance of the plant
B. WATER
3-4 cm of distilled water in a tall saucer (generally it is good to keep water at a level never less than 1/3 the height of the pot). Water produced by condensation, rainwater and generally all water that is free of minerals are also fine.
Why?
Bogs are ecosystems with an impermeable, mostly clay bottom, which does not allow rainwater to penetrate the lower layers. The result is permanently waterlogged soil that results from the condensation of atmospheric water vapor, which is naturally devoid of mineral salts.
Mineral salts, on the other hand, are commonly found in fresh water and in our aquifers and result from the dissolving of limestones that make up rocks and go into the waters of rivers and lakes. Drosera has adapted to grow in an environment devoid of mineral salts derived from water, particularly carbonates that would in the long run raise the pH of the substrate, irreparably damaging the plant.
Even in winter, it is possible to leave water in the saucer: the hibernaculum is able to resist the ice that might form in the saucer in subzero temperatures..
C. SUBSTRATE
50% peat and 50% perlite
Why?
Drosera does not tolerate nutrients. We avoid pH-neutral or nitrogen-amended peats often found in acidophilic potting soils. Peat must be pure.
Perlite is an inert substrate that helps aerate the substrate. In nature there is obviously none, but forced cultivation in small volumes (our pots) requires adaptation to increase the shelf life of the constantly wet substrate.
CAUTION: Do not breathe in unprotected perlite dust, moisturize it properly before handling it, it is a very fine dust and harmful to our lungs!!!
D. Winter
Never retire temperate sundew indoors. It is a plant that needs vegetative rest.
It is possible to shelter it under a porch or in a cold greenhouse but it must necessarily stay outside all year round.
Why.
Temperate sundews live in mountain environments where much of the year cold and snow prevent their growth. They have adapted to this environment and have evolved by vegetating very quickly in the few months available, however precisely because of the speed of their growth they use a lot of energy. Forcing their growth even at the end of the natural vegetative period would stress the plant so much that it would die.
When does it go into vegetative rest?
With the arrival of autumn and early cold weather, the leaves of temperate sundews will quickly begin to dry out and the plant to store as much energy as possible in the hibernaculum. Usually even in winter it is good to leave 1-2cm of water in the saucer. With the return of spring this protective hibernaculum will “hatch” and the plant will soon return to form leaves and flowers.
No fear then:temperate sundews at the end of summer will not die!
What to do in spring?
With the arrival of spring, temperate sundews will begin to “wake up” from their vegetative rest.At this stage it is advisable to gradually increase the water in the saucer to support the increasing water demands of the new leaves that are beginning to vegetate.
Shortly after awakening and after producing numerous traps, flowering begins. Almost all temperate sundews are self-pollinating, meaning that flower fertilization and fruit and seed production is spontaneous. When the flower stem dries out, it will be possible to collect the numerous black and very small seeds (smaller than grains of sand) and it will be possible to sow them right away. Sometimes the seeds need cold stratification, meaning that they will not germinate until they have felt a period of cold weather (which would correspond to winter in the places where they live). This is also an adaptation of the plant to survive the harsh climate.
For Drosera, it is not necessary to cut off the flower as it does not compromise the plant’s development that much, you can enjoy the bloom without worry!
What are temperate sundews?
As already mentioned sundews that live in temperate environments are few, below is a list of the various species belonging to this group:
SUBTROPICAL SUNDEWS
The term subtropical sundew encompasses all those sundews that in nature have adapted to a warm climate similar to the tropical climate however characterized by cool but not harsh winters. They are in fact plants that grow in South Africa, South America, and parts of Asia where the climate is somewhere between tropical and temperate.
As a result, subtropical carnivorous plants, in this case the subtropical sundew, do not require vegetative rest since, although the winter climate turns out to be colder than the summer climate, the conditions and temperatures in nature are not prohibitive and their growth will only be slowed.
Their natural environment can be compared to that of peat bogs because of the acidic pH and scarcity of minerals and nitrogen. Very often these sundews grow in soil that also consists of inert sand (i.e., which does not release minerals): a substrate that is definitely more percolating than peat, which, on the contrary, is able to absorb large amounts of water. However, the impermeability of the bottom layer prevents water from reaching the layers below, so even if sandy soil is present there it will remain wet and humid. Frequent rainfall, which some locations experience for much of the year, also contributes to this.
A. Sun exposure
They need direct sun to be at their best! With the rule of thumb of sheltering them from the wind and shading them during the middle hours of the day in the scorching summer months (they are not used to too high summer temperatures).
Why in full sun?
As with Dionaea muscipula, it is also an energy issue for Drosera; they need a considerable amount of energy, provided indirectly by photosynthesis, in order to grow fast and produce large amounts of the viscous substance essential for catching prey. Thus greater light intensity results in more vigorous growth.
In addition, this carnivorous plant takes advantage of light rays and the reflections they produce on glue droplets to attract insects! However, it is good to shelter them from the wind: a windy environment will cause the droplets to dry out excessively, reducing the trapping efficiency and aesthetic performance of the plant
B. Water
2-3 cm of distilled water in the saucer (at least 1/3 of the height of the pot itself).
Again, it is appropriate to give our plants mineral-free water: even subtropical sundews need an acidic pH and no nutrients in the soil..
As winter approaches, on the other hand, it is a good idea to decrease the amount of water in the container.
Why reduce water as winter approaches?
Although carnivorous plants belonging to the subtropical sundews group do not require vegetative rest, it is good to reduce water supply for two main reasons:
Any frost caused by our Mediterranean and/or temperate climate could freeze the water and irreparably damage most of the roots resulting in the death of the sundew.
Many of these sundews in their natural environment, as the winter period approaches, are affected by a decrease in rainfall resulting in a natural reduction in soil water levels.
C. Substrate
50% pure sphagnum acid peat and 50% perlite
Sometimes some subtropical sundews like peat and perlite mixes with equal parts quartz sand.
Why?
Drosera does not tolerate nutrients. We avoid pH-neutral or nitrogen-amended peats often found in acidophilic potting soils. Peat must be pure.
Perlite is an inert substrate that helps aerate the substrate. In nature there is obviously none, but forced cultivation in small volumes (our pots) requires adaptation to increase the shelf life of the constantly wet substrate. Many experienced growers use inert quartz sand in addition to the classic substrate or completely replacing perlite. This is to best recreate the natural environment of these sundews. However, it is not a must; sometimes it is used just for an aesthetic factor.
CAUTION: Do not breathe in perlite dust unprotected, moisturize it properly before handling it, it is a very fine dust and harmful to our lungs!!!
D. Winter
Subtropical sundews do not need vegetative rest and do not produce hibernacula.
Winters in subtropical climates are cool but not cold, meaning that temperatures drop but rarely fall below 10°c. In winter it is still possible to grow the hardiest species outdoors (e.g., Drosera capensis) but it is very important to shelter them from frost and reduce the water in the saucer.
Ideally, you should have a cold greenhouse in which to protect them. Alternatively, many growers use the interior space of double windows by taking advantage of the warmth of their home to create a greenhouse-like space in which to overwinter the plants, or a terrarium equipped with artificial lights. If you do not have a terrarium, it is normal to notice a loss of vigor and a slowdown in growth. As the days get longer and the temperatures rise, however, they will return to growth and bloom giving great satisfaction!
Below is a list of the most common plants belonging to the subtropical sundew group:
But what are winter-growing sundews:
These are sundews that have evolved in environments with extremely hot, dry summers and mild, rainy winters. They have thus evolved a growth strategy opposite to common subtropical plants: they vegetate in the mild winter months and go into summer rest, losing the vegetative part and often forming fleshy roots that serve the function of energy reserves.
Their cultivation differs from what has just been discussed in some respects that we will now discuss. As summer heat approaches, the amount of water should be minimized by adding an inch of distilled water in the saucer as needed, letting the saucer dry completely and adding more only after a few days. In this way the root remains hydrated and viable but the plant feels the “dry” stimulus needed to induce vegetative rest. With the end of summer and the arrival of cooler T’s we can start again with the classic water regime suitable for subtropicals: distilled water always present in the saucer up to at least 1/3 of the pot height.
During the winter months, temperatures should still remain above 10 degrees to ensure continuous development from late summer to spring. If T’s drop more, as happens outside in our latitudes, we will see a second freeze, this time due to excessive winter cold, with vegetative recovery resuming in the spring months.
Petiolaris complex Sundews
Petiolar sundews or petiolaris complex sundews (petiolaris complex sundews) are a peculiar and very fascinating group of sundews: in the wild they find their habitat in some regions of northern Australia characterized by hot summers with very frequent rainfall and temperatures even above 30°c and mild winters with scarcity of rain in which the temperature generally never falls below 18°c.
These sundews grow on extremely diverse substrates, some have been found on soils composed almost exclusively of sand, others on peaty soils but all have in common nutrient scarcity and an acidic pH.
These magnificent plants that resemble small fireworks pose a real challenge to the carnivorous plant enthusiast and in particular to the Drosera plant, as the real problem is not the composition of the substrate but recreating the right climatic conditions for their growth.
In this article you will find the basic points to be able to easily grow a Drosera petiolata.
A. Sun exposure
Petiolate sundews also love lots of direct light! In fact, in full sun they will develop their incredible colors to the fullest!
Why in full sun?
As with Dionaea muscipula, it is also an energy issue for sundews; they need a considerable amount of energy, provided indirectly by photosynthesis, in order to grow fast and produce large amounts of the viscous substance essential for catching prey. Thus greater light intensity results in more vigorous growth.
In addition, this carnivorous plant takes advantage of light rays and the reflections they produce on glue droplets to attract insects! However, it is good to shelter them from the wind: a windy environment will cause the droplets to dry out excessively, reducing the trapping efficiency and aesthetic performance of the plant
B. Water
The water to be used for successful cultivation of a Drosera petiolata must necessarily be demineralized (distilled or rainwater) since this sundew, like almost all carnivorous plants, does not tolerate the presence of mineral salts and nutrients in the soil.
In their natural environment during the summer it rains very often: excess water is not a problem if well exposed to the sun, it is generally advisable to keep a few inches of water in a tall saucer.
Winters in those regions are relatively dry; as the cold season approaches, it is mandatory to gradually reduce the water supply. At this stage, the plant will begin to retreat into a form of vegetative rest that does not involve hibernacula: slowly, as cold temperatures approach and water levels drop they will slow growth, forming a “rosette” of leaves devoid of trap and
villous appearance.
Why?
The hairiness that the leaf blade develops is nothing more than a form of protection from excessive heat. Normal leaf transpiration and the loss of water particles through stomata allow the plants normal metabolic functions. In this case the externally released water remains for a long period of time “clinging” to the hairs in the leaf surface before evaporating. In doing so there is an obvious reduction in epidermal temperatures due to the moisture present on the leaf, which functions as a kind of heat exchanger.
C. Substrate
Sundews belonging to the Drosera picciolata group are not particularly soil-demanding carnivorous plants as they can be grown in a mix of acidic blond sphagnum peat with perlite and fine quartz sand, in only acidic blond sphagnum peat and perlite, or in various mixes of them. Everyone can find the ideal mix based on the experience they gain over the years.
Two excellent mixes are the classic and timeless 50% acidic blond sphagnum peat and 50% perlite or 50% acidic blond sphagnum peat 20% perlite and 30% fine quartz sand. The basic rule is that the soil should be acidic and free of soil conditioners/nutrient
D. Winter
Winter for petiolate sundews grown in a temperate climate area is the real challenge.By following some small and easy rules, we could grow these beautiful carnivorous plants at their best even with our cold and wet winters.
As already mentioned, Drosera petiolata does not tolerate excess water and humidity in the cold months. These conditions would easily lead to fungal attacks that would quickly compromise the health of the plant.
To solve this problem, it is necessary to ensure dry soil and relatively low air humidity.
How can I do this?
At the end of the summer you should gradually reduce the water supply until a dry (not dry!) soil condition is achieved, which will be wetted from below whenever necessary in order to maintain a slight degree of moisture in the substrate. If you live in areas where winter temperatures fall below 10-15°c, it is advisable to have an indoor terrarium with a good air recycling rate to avoid the accumulation of moisture that is deleterious to this Sundew. Minimum temperatures should not fall below 18 degrees.
At this stage the plant will slowly begin to produce thicker, shorter and shorter leaves without functioning traps until it reaches the appearance of a “rosette, totally slowing down its metabolism until spring.
This resting condition is necessary to allow the plant to follow its natural cycle. Therefore, it is not recommended to let petiolate sundews vegetate all year round.
What to do in spring?
Spring is a somewhat delicate period for Petiolate sundews, in fact in nature it coincides with the exponential increase in rainfall, an event that occurs at the same time as temperatures rise. To properly simulate this period and avoid mold attacks, it is necessary to “wake up” Petiole Sundews gradually. To do this, it is recommended to gradually increase the water supply: as the moisture and water in the soil increase, the Drosera petiolata will begin to wake up. When outside temperatures allow (> to 18 degrees) you can place the pots outside in full sun using the classic growing system used for Dionaea, Sarracenia and subtropical sundews. It is under these conditions that these bizarre but fascinating plants will give their best, especially in the scorching summer months.
Here is a list of the main species excluding the many horticultural hybrids:
PIGMEE DROSERA
The pygmy sundews group includes more than 50 species of small and curious carnivorous plants, only a few centimeters in size and often producing flowers larger than the plant itself.
In the wild they are found in an area that includes southern Australia and parts of Tasmania and New Zealand where winters are mild and very wet while summers are hot and with little rainfall.
They are easy to grow and very prolific plants: in fact, their peculiarity is that they asexually produce buds at the end of summer, these buds usually germinate in a very short time creating clones of the mother plant, often carpeting and colonizing areas that are also quite large for their minute size.
They proliferate and colonize soils that are predominantly sandy and therefore relatively dry and poor in nutrients, which is why they possess an extremely long root system in relation to their size, in fact the roots, which are as fine as hair but up to tens of centimeters long, are able to absorb water from the subsoil at a rather remarkable distance.
A. Sun exposure
As with all sundews, pygmy sundews need direct sunlight in order to live at their best and carry out their activities as tiny predators.
Why in full sun?
As with Dionaea muscipula, it is also an energy issue for sundews; they need a considerable amount of energy, provided indirectly by photosynthesis, in order to grow fast and produce large amounts of the viscous substance essential for catching prey. Thus greater light intensity results in more vigorous growth.
In addition, this carnivorous plant takes advantage of light rays and the reflections they produce on glue droplets to attract insects! However, it is good to shelter them from the wind: a windy environment will cause the droplets to dry out excessively, reducing the trapping efficiency and aesthetic performance of the plant
B. Water
In the wild, Pygmy Sundews face torrid, dry summers where they enter a state of dormancy to awaken and vegetate in their winter period, which is characterized by abundant rainfall and mild weather.
Unless you have a terrarium this is rather difficult to reproduce in a temperate climate: actually reproducing these conditions is not necessary as most pygmy sundews vegetate happily all year round and do not require the dormant period.
However, it is a rule of thumb to use only distilled, rain or condensation water as with all carnivorous plants.
In summer the usual inches of water in the saucer should be maintained while in winter the water supply should be reduced.
Why give water in summer if they go dormant in nature?
Pygmy sundews are very hardy plants and we can “fool” them by pretending that our summer is their winter. Very simple.
C. Substrate
As already mentioned Pygmy sundews are extremely versatile plants: however, the essential rule of using are acidic blond sphagnum peat-based substrates applies.
The mix 50% acidic blond sphagnum peat and 50% perlite is fine for all Pygmy Sundews but it is possible to experiment with other soils by replacing the perlite with quartz sand, making a mix between these two or covering the last layer of mix with 2-3cm of pure quartz sand to recreate what is their natural environment.
Since the root system of these plants is rather fragile they do not particularly like repotting, especially once they have reached maturity, if you decide to repot, you should pay special attention to the substrate cake to avoid damaging the roots as much as possible.
D. Winter
Pygmy sundews do not need any kind of vegetative rest.
How do I do this in winter?
Many growers during the winter period bring pygmy sundews inside a terrarium or double window. This is true for the more delicate pygmy sundews in geographic areas where winter temperatures expect frequent frosts. Generally, it is sufficient to reduce the water supply (not necessarily gradually) to prevent the water in the saucer from freezing, irreparably ruining the roots.
They are very hardy plants but watch out for frost! Ideally, they should be placed inside a cold greenhouse.
One of the peculiarities of pygmy sundews is the production of buds, this event coincides with our autumn and therefore with the lowering of temperatures (usually around October-November) and is an extremely effective form of asexual reproduction since the buds, produced in the center of the rosette, upon reaching maturity are immediately responsive and ready to germinate.
What to do in spring?
with the arrival of fine weather, the only thing to do is to place them in the sun again and increase the water supply.
Caution. Most pygmy sundews are not long-lived (a couple of years usually), which is why they have developed this type of asexual reproduction involving the production of buds: in order to briefly colonize as much area as possible. Therefore it is a good idea to collect the buds and replant them in the pot itself or in a new pot. In a short time they will completely carpet the surface creating a spectacular effect to say the least!
Below is a list of the most common pygmy sundews:
TUBEROUS SUNDEWS
A fascinating group of carnivorous plants, tuberous sundews are a particular type of sundew native to Australia and parts of New Zealand and Tasmania. Areas characterized by mild, rainy winters and hot, dry summers.
They grow on mostly sandy soils (inert noncalcareous sand) where they sink their roots deep producing tubers in order to survive the summer climate. In fact, this type of Drosera vegetates a few months of the year, at the beginning of the winter season, coinciding with the first rains, sprouting from the soil and growing rapidly until flowering.
They are very heterogeneous-looking plants, some having a prostrate (or “rosette” appearance, that is, close to the ground) with broad leaves lying on the surface of the substrate. Others, on the other hand, stand tall, some a few inches, while others can reach over a meter in length.
A. SUN EXPOSURE
Full sunshine during the vegetation months, which for us coincide with the months between September and May.
Why?
For the energy reasons we already know, as tuberous sundews are very fast-growing carnivorous plants they need a lot of energy.
Should the pots with tubers also be exposed to the sun?
It is not necessary, although the tubers are very hardy it is preferable to place the pots under cover during the summer months to prevent the excessive heat of a closed system such as a pot from damaging the tuber of the more delicate species.
B. WATER AND SUMMER/WINTER MANAGEMENT
Always use demineralized, rain or condensation water.
Tuberous sundews need plenty of water during the vegetative growth period and dry soil during the summer.
How and when should I water tuberous sundews?
The tubers are a form of defense that these Sundews use to shelter themselves from the heat and dryness of the summer period.During the summer, the pots containing the tubers should not be watered because with too much water they could easily rot.
When the tuberous Sundews begin to dry out and form the tuber, it is necessary to decrease the water supply gradually by letting the soil dry out completely. After that it is advisable to irrigate every 3 weeks, possibly with the aid of a sprinkler, only from above and with a few sprinkles to ensure a minimum water supply necessary to keep the tubers turgid.
With the arrival of cool September we behave differently: we can start moistening the soil from above more frequently and then gradually watering from below, adding the classic 2-3 cm of distilled water in the saucer. In this way we will simulate the beginning of the rainy season and the tuberous sundews will sprout from the soil in a short time.
But doesn’t it get too cold in winter?
In many areas especially in northern Italy the answer is yes!
Most tuberous sundews, those that are less demanding and can tolerate temperatures even around 10°c (e.g., Drosera foliosa, Drosera auricolata, Drosera hookeri…), grow just fine inside a cold greenhouse or double window. The classic places where we shelter subtropical sundews for the winter!
Many growers use terrariums for the more demanding tuberous sundews, this solution is advisable only for prostrate-shaped sundews as upright tuberous sundews tend to grow too tall to manage inside an enclosed system.
C. Substrate
For less demanding tuberous sundews, the classic mix of 50 percent blond acidic sphagnum peat and 50 percentperlite is fine, however, almost all tuberous sundews grow on sandy soil so ideally use a mix of 30 percent acidic peat and 70 percent quartz sand with mixed grain size (fine to a few millimeters maximum). It is advisable to use dark-colored sands as many tubers are white or yellow in color and could be easily confused with perlite or light-colored sand.
It is advisable to use pots at least 10 centimeters high as the roots of tuberous sundews go deep to form the tuber. In addition, for an aesthetic factor, you can cover the substrate with 2-3cm of pure sand in order to recreate, as much as possible in pots, a “nature split” effect.
Below you will find a list of the most common species of tuberous sundews and some subspecies as the nomenclature of these plants is constantly evolving:
QUEENSLAND SUNDEWS:
The Queensland sundew group is extremely small and includes only 3 species of sundews and 1 artificial hybrid.
This particular group of carnivorous plants finds its natural habitat within rainforests with a tropical climate in northeastern Australia, a region known precisely as Queensland.
In this tropical environment, rainfall is very frequent and temperatures never fall below 15°c throughout the year. These particular Sundews specialize in catching small insects, which, thanks to enzymes produced by specialized glands, are digested very quickly.
A. SUN EXPOSURE
Filtered light or shade, they do not like direct sunlight
Why?
As mentioned earlier these Sundews grow within tropical rainforests in an extremely humid understory environment where they have developed relatively fragile and sun-sensitive tissues.
Drosera adelae is the most adaptable species and tolerates a few hours of sun exposure well as long as you give it plenty of water and ensure high air humidity.
Drosera schizandra, on the other hand, is the most delicate, not tolerating direct sun exposure and too much other temperatures. This sundew grows in the mountains of Queensland and has also been found at 700m above sea level, so it likes milder temperatures (around 20°c) and very high humidity.
B. Water
Use only demineralized, rain or condensation water. As always, add a few inches of water on a saucer and make sure it is always present.
C. Substrate
50% acid blond sphagnum peat moss and 50% perlite, it is advisable to cover the substrate surface with a few clumps of live sphagnum moss.
Why is sphagnum moss useful?
It is advisable to use sphagnum moss because, in addition to giving a beautiful natural effect, it helps keep humidity high near the plant. Be careful, however: it is best to thin the sphagnum moss often as it may overgrow by overgrowing the sundew.
D. Winter
As Queenland sundews are tropical carnivorous plants they do not go into a dormant period and it is necessary to guarantee them temperatures never below 15°c.
Drosera adelae is the hardiest and can overwinter peacefully inside a cold greenhouse or double window and can tolerate temperatures lower than 15°c for a short time.
Drosera prolifera and Drosera schizandra are more delicate; ideally, they should be grown inside a terrarium with artificial lights and controlled temperature.
Below is the list of Queensland sundews only:
TROPICAL SUNDEWS OF SOUTH AMERICA
This family includes a large genus of Sundews native to South America in mountainous areas with a predominantly tropical climate characterized by temperatures generally not exceeding 25°c and heavy rainfall. For most of these sundews, cultivation is fairly straightforward: they need temperatures that are not excessively high and like a temperature change between day and night that is around 10°c.
In this section devoted to the beautiful South American Sundews we will define the key points for the successful cultivation of most of them.
A. SUN EXPOSURE
Like most carnivorous plants belonging to the genus Drosera, South American Sundews need plenty of light and sun, however to avoid excessive temperature rise it is advisable not to expose them to direct sun especially during the hottest hours of the day.
Many experienced growers prefer to grow these carnivorous plants inside temperature-controlled terrariums (ensuring temperature change) and it turns out to be the perfect solution for even the most demanding South American Sundews.
B. Water
Plenty of distilled, rain or condensation water, ideally leaving a few inches constant on a high saucer.
Why?
As with all carnivorous plants, this type of Sundew lives in acidic environments with mineral and nutrient scarcity. In their natural habitat, rainfall is very frequent-that is why it is advisable to never let them lack water in the saucer.
C. Substrate
50% acidic blond sphagnum peat and 50% perlite
South American sundews are not particularly demanding in terms of substrate, the important thing is that it is totally free of soil conditioners, nutrients and minerals and has an acidic pH.
D. Winter
Being tropical, South American sundews fear cold weather. Some such as Drosera tomentosa are more hardy than others that may perish if exposed to temperatures below 15°c for an extended time.
However, they are generally able to overwinter inside a cold greenhouse or double window without major problems.
Ideally, they should have a well-ventilated terrarium equipped with artificial lights, in which they can replicate their natural conditions typical of tropical upland plants: constant year-round temperatures of around 15 degrees at night and 20-25 during the day.
What happens if I choose not to grow them inside a terrarium?
If we opt to overwinter in a cold greenhouse or double window, we have to pay special attention to the temperatures; as with subtropical sundews, South American tropical sundews will also slow down their metabolism in winter (without, however, having a real resting period), managing to withstand, in some cases, even temperatures around 5-8 degrees. During this unfavorable period, the goal will become plant survival, giving up a little on aesthetic performance. As spring arrives, they will become vigorous and colorful again!
Below you will find a list of the most common South American Sundews:
SUNDEWS DISEASES AND PESTS:
During the summer period, sundew can incur attacks by pests and fungi, let’s see together which ones.
PARASITES:
Aphids: variable-colored stinging insects (usually white or green) a few mm large, visible to the naked eye and easily eradicated. They sting and suck plant sap causing mainly leaf deformities and small galls.
Why?
The saliva of these parasites produces auxin-like substances. Auxins are plant hormones that, along with others, control the plant cell cycle. Disruption of the hormonal balance causes the plant to produce galls, small clusters of undifferentiated cells (tumors) that appear as leaf bulges.
Aphids can be removed manually and can be easily eliminated with organic pyrethrum-based aphicidal products. Repeat the initial treatment after 10 days to also eliminate any new hatchlings from the initially laid eggs.
Mites:. It is an arachnid (not an insect) of very small size (0.5mm for females and even less for males) with stinging mouthparts. It stings the leaves of our plants to suck sap and feed. The main symptoms associated with red spider mite are leaf discoloration and leaf wilting/ browning much faster than normal, often when it should not.
How to fight it?
A contact acaricide insecticide for minor infestations followed by systemic acaricide for major recurrent infestations. If neglected, it can become really difficult to eradicate this pest.
Winter-growing sundews are less fearful of pest attacks because pests are much more prolific and active during the warm months.
FUNGI:
Botrytis: commonly called “gray mold,” is a type of fungus that attacks the tissues of debilitated plants. Its course is very rapid and can lead to plant death in as little as a few days.
Botrytis can occur at any time if conditions are not optimal, especially when there is poor air circulation. However, it is easily eradicated with specific products found on the market.
HOLIDAYS
What about when we are not there?
Nothing could be easier!
Most plants belonging to the genus Drosera, as well as for Dionaea muscipula are not afraid of water stagnation, on the contrary! It needs it!
Using a suitably sized piece of expanded polystyrene or any other floating support, a floating platform can be made for our pot.
1) We drill a hole in the center of our floating raft so that the jar can be placed there. The holes in the bottom of the jar must protrude from the bottom surface of the raft.
2) We choose a bucket or container large enough to hold the water needed to cover the plant’s water needs for as long as we are away (be careful to also consider evaporation and not just water absorption by the plant)
3) We place the raft with the pot in the container filled with water. Make sure the buoyancy is stable!
This way the raft will adapt to the water level which will gradually decrease keeping the peat moist and the aerial part dry!
CONCLUSION:
The world of carnivorous plants belonging to the genus Drosera is definitely diverse and it is therefore difficult to encapsulate everything within a single article.
We aim to devote more time and more lines to each individual “cultivation group” with specific articles
Until then we hope that you will find in this writing some useful foundations to start your own cultivation tests
Good luck
G.Mehle / V. Guidolin
No Comments