Expert: Christopher Littrell - 2/25/2011

Question
Hi Christopher,

My girlfriend placed a Sundew on my desk this morning as a birthday present. Obviously I'd like to care for it well, but alas I have little knowledge of these. The first problem is the label doesn't give the species (only "Part Shade", Indoors well lit", "Good for Pots", and "Water well"), but I live in South Africa so I'm guessing it's Vynbos related (though I'm up in Johannesburg, so about 1000km from the Cape, and much higher in altitude). Would you be able to send me a dichotomous key or something, that I could use to identify it? The leaf is about 15mm and it has a tall (25mm) flower (stalk/bud).

Before I started reading up, I noticed an expiring fly (it looked like a Lucilia sericata) trying to walk about on the windowsill where I've placed the Sundew, so I picked it up and placed it next to leaf and it duly got stuck. Is this contra indicated? I haven't seen the leaf curl up or anything of the sort. Along this line of question though, I work in an insectary with mosquitoes, would they be suitable prey?

Answer
Hello Oliver,

The description does seem to cover a number of the dozens of possible Sundew species your plant could be. There are several species in South Africa, particularly along the Cape, that grow naturally there, and there are a number sold around the world commonly from other areas, like Australia.

Best bet would be to look at online sites with pictures to identify the plant more directly. Each Sundew has some distinct leaf shapes and sizes. Some of the small round leaf varieties can look rather alike, but the larger, long leaved varieties are often easier to tell apart. Try cobraplant.com to observe some Sundew varieties.

Follow the general directions for now, making sure to keep the plant in at least partial to indirect sun all day. There are a few Sundews that are intolerant of direct sun and can burn, but many are full sun or very high intensity light lovers. Once you have more of a handle of what species you have, you will be able to send me a followup with more specific questions or even determine, from further reading, their requirements. Place a large tray under the pot with up to 1/4 the pot in clean, mineral free water. Mineral laden water is harmful to the soil type (acidic sphagnum moss) that these plants require and can damage the plants and kill them eventually due to the chemical changes in Ph in their soil. Distilled and reverse osmosis water is best, but soft (not salt softened) water below 50 parts per million would be fine to use.

In most cases, the plant will capture its own prey, but you can certainly drop a small insect on the plant every once in a while if it is healthy and shows signs of plenty of dew production and growth. Mosquitos are a perfect prey item for Sundews. Some Sundews will curl their leaves and some will not. Drosera adelae (Lance Leaf Sundew), from Australia, does not curl its leaves much at all, but does move its tentacles slowly over several minutes. Other Sundews, like your native Cape Sundew, Drosera capensis, can and will curl its strap shaped leaves all around flies and other insects as they struggle, sometimes within a mere 30 minutes.

Never fertilize the soil of your Sundew as that can also damage the Ph of the soil and burn the roots of the plant, which are not capable of much nitrogen absorption as the leaves evolved for.

Christopher