The genus Drosera has around 160 species, found, all over the world. In fact, save from the frozen Arctic and Antarctic regions, no continent is without Drosera. In the UK, we have three species that are natural in these parts: imagine - CPs on your doorstep! Not the tropical jungle plants most people associate carnivore with. The common name is Sundew, which is derived from the mucilage that adorns each gland on the leaves of all plants glistening in the sunlight, reminiscent of spring sunshine on early morning dew. Although the common name seems almost delightful, this hides a morbid side to the plants, or more specifically, their prey capture method. Generally, sundews are rosette-forming plants with glands protruding from the surface of the leaf. At the end of each of these glands is a drop of sticky mucilage, and these double as both lure and snare for insect prey.

 Trap

  Imagine you are a flying insect, happily soaring over picturesque savannah in the warm sunshine. Out of the corner of your eye, you spot what appears to be drops of luscious nectar glistening in the light, begging you to take a taste. With a spring in your step (or wings, I suppose!) you descend towards the attractive jewels, and as you get closer you begin to smell that sweet smell while beginning to imagine the gratifying taste. Closer still, and you can almost touch the nectar as it seemingly expands in front of your eyes. And then, just as you touch down in an apparent heaven on earth, your leg becomes a little stuck on the nectar. Gleefully, you try to pull it free to begin to gorge on the bounty of nectar before you, but another leg gets stuck. And another. And another.

   In panic, you try frantically to escape the clutches of this 'killer nectar' by beating your wings hard, but your legs are stuck firm. Your wings are stuck now, and it seems as if the plant is moving to encase you. Still struggling, you find yourself becoming more and more confined. There is a burning sensation across your wriggling body, as the plant begins to excrete digestive enzymes - the life is literally being sucked out of you. If you are lucky, you'll suffocate quickly. If not, you are subjected to a slow, lingering death. Welcome to the land of the sundews.

  Although the above description may sound like a work of insect horror fiction, it is in fact near reality. Although as we will see later there are many types of sundew, the trapping mechanism is common across them all. The 'nectar' on the end of the glands is a sticky liquid glue which is capable of ensnaring an insect larger than the leaf itself. Once prey becomes stuck on one of these blobs of glue, any frantic struggling will simply cause it to come into further contact with neighbouring glands, pinning the animal to the leaf. Some species have retaining glands which fold from the outside of the leaf in towards the centre to help to restrain the insect. Some species have even evolved to fold the leaf itself around the victim, thus ensuring a meal. For most insects, death is caused by suffocation since the breathing holes on the side of the insect soon become clogged with mucilage.

   Once prey is pinned down, the leaf secretes digestive fluids from sessile glands along the body of the leaf. These work on reducing the fleshy internal part of the insect into a nutrient soup which is subsequently absorbed by the plant. Once digestion and absorption is complete, the leaf returns to its ready state, leaving to dried exoskeleton to be washed away by rainfall, or simply left as a macabre warning to other insects.

  Types of Drosera ( see full list bellow )

   There are many ways to divide up species of Drosera into various groups. As far as I know, there is no right or wrong way, so here is the list that I think is most commonly found:

 Temperate species:

   These sundews form winter resting buds (called hibernacula) during the cold winter months seen in temperate climates (like the UK) to protect themselves from the effects of these cold temperatures. All three Drosera species in wild in the UK are in this group: D. rotundifolia, D. anglica and D. intermedia. Also grouped here is the two subspecies of D. filiformis, namely D. filiformis ssp. filiformis and D. filiformis ssp. tracyi.

 South African species:

   South Africa (SA) is home to so many endemic species of sundew that it may be fair to class them separately. Apart from their geographical location though, there is not much common between the appearance of the plants. D. capensis is from the Cape region of SA and has strap-shaped leaves held semi-erect on long petioles, while D. aliciae from the same region has wedge-shaped ground hugging leaves forming a rosette. D. slackii (named after Adrian Slack) was discovered in SA in the early 1980s. Other species include D. cuneifolia, D. collinsiae and D. dielsiana amongst others. One exceptional species, which fits in this section better than anywhere else, is D. regia - the King sundew. This species is rare in cultivation and rarer in the wild, but so unique and beautiful with large, stiff sword-shaped leaves stretching for up to 60cm (around 2 feet).

 Other rosette-forming species:

  These plants are found all over the world, and some species are pan-continental. They form rosettes of ground-hugging leaves and are in active growth all year round. Species in this category include D. spatulata, D. capillaris, D. hamiltonii and D. montana amongst others.

  Pygmy species:

  These species are - guess what - small! On the whole, they have rounded leaves with glands on the end of petioles held in a rosette fashion, and most are less than 2.5cm (1 inch) in diameter. The majority are found in Australia, where they go dormant during the dry summer months and come into active growth during the wetter winter. There are many species which fall into this category - around forty - and these include D. scorpioides, D. pulchella, D. mannii and D. callistos.

 Tuber-forming species:

  This group of plants also hail from Australia, and survive the dry summers by hibernating in tubers under the ground. While this group can be split into further subgroups, there is simply not space here to do that effectively! These species are popular with collectors since they flower at a time of the year when most CPs are dormant. Examples in this large category are D. peltata, D. gigantea, D. macrantha, D. stolonifera, D. ramellosa, D. macrophylla and D. whittakeri amongst others.

 North Queensland species:

   Grouped together here are three species which share remarkably similar conditions and exist no where else on Earth! They are: D. adelae, D. prolifera and D. schizandra.

 Fork leaved species:

   These species all grow in eastern Australia, with one growing in New Zealand also. Debate rages over whether or not all the plants with forked leaves are forms of D. binata, but currently D. dichtoma and D. multifida are considered distinct enough to be separate species. Each species listed here has at least one other form, and a popular hybrid is between D. dichtoma "Giant" and D. multifida "Extrema" which was first bred by Adrian Slack, who named it D. "Marston Dragon".

 In the Wild

  With such a wide geographical spread, it is not surprising to find that some species are thought by some as CP weeds, while others are extremely endangered. Nevertheless, it should be stressed that no matter how common any plant, be it carnivorous or not, are in an area, they should not be removed by any collectors. Exceptions of course occur when those removing plants are botanists or connected scientists doing so for research and/or conservation.

 In Cultivation

  With the growth in tissue culture, even the rarest Drosera in the wild are either available or soon to be available to those in cultivation. In mainstream garden centres across the UK you are likely to find D. capensis, D. aliciae and possibly D. adelae on sale at some point during the year, but over and above that it is unlikely you will find much. However, many private nurseries and growers in the UK seem to be able to churn out batch after batch of sundews, so the chance to expand your collection is always there!

   Since the geographical range of these plants varies hugely, so do their cultivation requirements. As a general rule, a soil mix of 1 part sphagnum moss peat to one part sand will suit most species, and will enjoy sunny conditions using the tray method for watering. Some of the more uncommon species prefer different conditions, but if you have these species you’ll likely not have learned anything from this article!  I have a bog garden here in Essex England that has plants like D. capensis, D. aliciae, D. binata and other types of Droseras that have come from warmer places. There are a little bit smaller then ones I grow in the greenhouse.

 Further Reference  See my book list on this site.