Sundews (Drosera)

CARING FOR YOUR SUNDEW

Drosera

Sundews (Drosera species) lure their prey with sweet drops of nectar on their leaves. When an insect alights upon a leaf, it finds itself stuck as if to fly paper, and becomes dinner for the plant. Sundews come from all over the world, and may be temperate or tropical, so their care varies according to type (see notes on some specific species at the end of this sheet).

Soil: Most sundews grow well in a mixture of 1 part sand or perlite and 1 part peat moss. Use white sandblasting sand, and wash it well with rain water or distilled water. Moisten and break up the peat moss well before mixing with the sand. Wear gloves. Do not use ordinary potting soil or garden soil.

Water: If you have killed a carnivorous plant, it was probably the water you used. Typical tap water or well water has too many minerals and salts that will build up in the soil of your plant, and within about six months it will die. An occasional watering with such water will not be deadly, but be sure to flush it out thoroughly with pure water after using tap or well water. You can buy distilled water (the kind you put in your iron, not mineral or spring water), collect rainwater from a downspout, or use a reverse osmosis water purification system.

Watering frequency: During the growing season (spring through early fall), most sundews like to stay very wet, even soggy. Sit them directly in an inch or two of pure water in large saucers or trays. This makes for easy vacation tending: just sit them in more water than usual while you're gone for a few days. To prevent mosquitoes from breeding in this water, use mosquito dunks or granules (they contain a bacteria called Bti that kills mosquito larvae, but does not harm other organisms). The water in the trays can occasionally dry up but be sure not to let the plants themselves dry out. During late fall through winter some sundews need to go considerably drier, though never bone dry. Keep these dormant types barely moist, and do not sit any sundews in water during winter.

Light: Most sundews like a lot of sun and like to spend their summers outside.  If you put them out, acclimate them the first time you put them out in direct sun.  Start them in a little morning sun and gradually move them to more sun over a week or two. They also grow happily indoors on a sunny windowsill or under a fluorescent shop light. Keep them within 6"-8" of the light and change the light bulbs every spring, as the light capacity diminishes considerably after just one year.

Pots: Even the tiniest of sundews have surprisingly long roots, so use a deep pot. Start with 4" or 5" plastic pots. As they grow into a colony, you can pot up to at least a 6" pot. Most sundews like to share pots with other carnivores: try planting them at the base of a potted pitcher plant, or plant them in a mixed "mini-bog" planter. Many sundews grow very well in terrariums.

Fall and Winter Care: Many sundews do not require a winter dormant period and can be grown at average household temperatures year-round. For those that do require a dormancy, from late fall through February, keep them in a cool cellar or garage (night temperatures between 30 and 45 degrees). If there is no window, set up a shop light above your plant, attached to a timer to give it about ten hours of light a day. Keep your dormant plant only barely damp in the winter; never let it sit in water. You can also refrigerate your sundew for a couple of months: just stick the pot in the fridge, and check it every week or two. Water it if it starts to dry out (it should be barely moist). You don't need to provide light while it is in the fridge since it is consistently cold.

Feeding: If your plants spend the summer outdoors, they will catch all the food they need. Indoors, sundews will usually feed themselves on fruit flies or gnats, so supplemental feeding is not usually required. Do not use chemical fertilizers on your plant: the salts can damage and/or kill them.

Pests: You might be hoping that your sundews will kill all the bad bugs in your house and garden. Sundews may occasionally catch a mosquito, but generally these are not attracted to the sundew. More likely, your sundew will catch tiny gnats and fruit flies. As to houseplant bugs (e.g. aphids), sundews can be attacked by them the same as any other plant. The easiest way to deal with pests is to drown them by submerging the entire plant in pure water for 24 hours. Sundews normally experience brief flooding, and will not be harmed by it, but it should kill most of the pests.

Propagating: If you follow these instructions by the end of a year or two you will find that your plant has grown well and may have seedlings sprouting all around it. The best time to transplant these young sundews is at the start of new growth in the spring. Be gentle when you pull them out, remember that they have long roots!

NOTES ON SEVERAL SPECIES OF SUNDEWS:

Drosera adelae is a tropical sundew from Australia that prefers to grow between 60 to 80 degrees year-round, and thrives in terrariums. It does not like full sun, preferring to grow under a fluorescent shop light, or in an eastern window. If outside for summer, keep in shade or morning sun. Keep it quite moist year-round. It likes a loose potting media. A good mix is 1 part sand, 1 part peat moss and 1 part long-fibered sphagnum moss. It is common for this sundew to go through a late winter dying-off cycle. Older plants tend to die after a year or two, but newer ones soon pop up to take their place, so don't panic!

Drosera capensis (Cape sundew) from South Africa is the weed of the carnivorous plant world, happily sowing its seeds and coming up in other pots of carnivorous plants, so beware! It should be kept away from pots of sundews as it can quickly take over slower growers. It is a rewarding and easy plant to grow in a pot by itself, and can grow on a windowsill year round or in a terrarium. Indoors, it likes plenty of sun, or it can be grown under a fluorescent shop light. Outdoors, it needs to be shaded from the afternoon sun, and grows best when temperatures are moderate. It does not require a winter dormancy, but is tolerant of cool (40 degrees) winters, and can withstand brief periods of freezing temperatures.

Drosera spathulata is sub-tropical and self-sows almost as much as the Cape sundew. It does not require a winter dormancy, though it can handle a cool (40 degrees) winter, if potted with other plants that require dormancy. Full to part sun.

Drosera intermedia is native to Europe, North America, and South America, and can be temperate or tropical, depending on its native origin. Full sun and very wet.

Drosera filiformis is native to the east coast of the United States. Leaves are tall and thin. This species goes completely dormant in winter, and requires a cool winter rest. Full sun and very wet.

Drosera dichotomoa and Drosera binata hail from Australia. They go dormant briefly in winter, and are tolerant of brief freezes, but if the root freezes completely, they may die. Full sun and very wet.



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