Drosera filiformis and Drosera tracyi are two closely related North American species. Drosera filiformis is found on the Atlantic coast from North Carolina to Nova Scotia along with a few populations in the Florida panhandle. Drosera tracyi is found along the gulf coast from Louisiana to southern Georgia. Both species form hybernacula in the winter although D. tracyi is found in an area generally considered warm temperate.

There are two varieties of Drosera filiformis found in Florida the Seed Bank has called "Florida All Red" and "Giant" but they have not been officially described. The "Florida All Red" form of D. filiformis now simply referred to as "Florida" requires minimal winter dormancy and makes an excellent terrarium plant. The "Giant" form is intermediate in size between D. filiformis and D. tracyi. This plant most likely is a hybrid between the two species.

The Atlantic coast Drosera filiformis requires a definite winter season to survive long term. You should grow them outside year round if you live within their natural range of USDA zones 6 and 7. If you live in a colder region, move the plants into a protected area after they have gone dormant. It is especially important they have protection from late spring frosts. If you live in zones 8 and 9 the plants should do OK. If you live in zones 9 or warmer grow the Florida form outside.

D. tracyi is found in USDA zone 9. It requires winter protection if grown in a colder climate and is especially sensitive to early and late freezes. We had trouble growing it outside in zone 9 in northern California which may have been a result of the long wet springs. Consider growing Drosera 'California Sunset' instead. It can handle winter better than D. tracyi. Or grow it in a greenhouse.

If you want to grow D. filiformis in a terrarium, it is best to grow the D. filiformis "Florida" form. The seeds germinate without stratification and some of the plants do not go dormant. Most will form loose hybernacula that last a month or so before the plant starts growing again. This plant may be grown outdoors in summer but needs to be in a warm greenhouse or other location that does not freeze during the winter. In a terrarium the "Florida" form may not develop the deep red color it would in full sun outdoors.

Seeds of D. filiformis and probably D. tracyi need a "winter" to germinate. The usual way to do this is to give the seeds a few weeks of damp cold stratification. You can put pots planted with the seeds in the refrigerator for 4 weeks. An alternative is to put the seeds in a small plastic bag with damp peat or finely chopped sphagnum moss in the refrigerator. The seeds and moss can be carefully spread over the surface of the soil in a pot after stratification. Or you can be put pots planted with seed outside in the winter and allow the seeds to sprout naturally.

No matter how you handle stratification, the seeds should not be buried when you want them to germinate. A pot with a 50:50 mix of peat and sand usually works well.D. filiformis and D. tracyi like large tall pots and can rot if the surface of the soil is too wet. You can mix extra sand into the top 1 cm of soil or even use pure sand the thickness of the hybernacula. The pots should always be sitting in water. Please see Sowing Seeds Step-by-Step for more details on starting seeds and Growing cold temperate Drosera for more information on growing the plants keeping in mind that D. tracyi is rather cold sensitive.

Make sure you feed your plants well if they are not catching many insects on their own. You can use rehydrated dried blood worms or foliar feed the plants with a dilute liquid fertilizer.

-- John Brittnacher

For more information please see:

Robinson, James T. (1981) New CP Cultivar Received in 1980. Carniv. Pl. Newslett. 10(4):95

Sheridan, Philip (1978) New Jersey Pine Barrens. Carniv. Pl. Newslett. 7(4):107-109 ( )

Butler, David E. (1985) Drosera Hybrid Found in Pine Barrens. Carniv. Pl. Newslett. 14(1):15-18 ( )

Schnell, Don (1995) Drosera filiformis Raf.: One species or two?. Carniv. Pl. Newslett. 24(1):11-15 ( )

Hummer, John H. (1998) A noteworthy Florida find: Drosera filiformis var. tracyi (Droseraceae). Carniv. Pl. Newslett. 27(3):89-90 ( )

Rice, Barry A. (2011) The thread-leaf sundews Drosera filiformis and Drosera tracyi. Carniv. Pl. Newslett. 40(1):4-16 ( )