1263 Drosera spp.Common Names: sundew,catch-fly Family: Droceraceae (sundew Family)
There are more than 100 species of sundews, small, insectivorous rosette-forming perennials that grow in acidic wetlands. Sundews are characterized by the presence of gland-tipped hairs on the leaf surfaces. These stalked glands are sticky on their tips, and serve to trap and digest insects that have the misfortune to alight upon them. Most of the Drosera species grow as small, low lying rosettes, often no more than 2-4 in (5-10 cm) in diameter and not much taller, except for the flower stalk which may rise a few inches above the leaves. The leaves are narrow near the base and usually spoon shaped at the ends which are covered with red or green hairs tipped with mucilaginous beads that glisten in the sun like morning dewdrops. The flowers are borne on erect scapes arising from the center of the rosette. There are up to 25 flowers arranged in a spike, each opening for only one or two days, from bottom to top. The flowers have five white to pink petals, the color varying even within a species.
Drosera brevifolia (dwarf sundew), and D. capillaris (pink sundew) are both very small, just 1-2 in (3-5 cm) in diameter and less than an inch (2.5 cm) tall. Both species can be bright red or purple when growing in full sun. D. capensis, Cape sundew, is a little larger, with spoon shaped leaves 2-3 in (5-7 cm) long, forming a rosette around 6 in (15 cm) across. It has rose colored flowers that stand several inches above the leaves. D. filiformis (threadleaf sundew) is a little different, with threadlike leaves (not spoon shaped) that stand upright 4-6 in (10-15 cm) tall. D. tracyi (formerly considered a variety of D. filiformis) has erect filiform leaves than can sometimes stand as much as 36 in (50cm) tall.
All of the sundews grow naturally in acidic, nutrient-poor, consistently wet soils, usually in full sun. Some sundew species (especially D. capillaris) are extremely robust to disturbance and are often among the first plants to recolonize a wetland that has been severely disturbed by logging, ditching or burning. There are five species of sundews occurring naturally in Florida and fewer than a dozen in the US. Africa and South America each have 20 or so species and there are around 100 species known from Australia.
Light: The sundews grow best in bright sun. Under glass, keep them in bright, but not direct, sunlight. Outdoors, they thrive in full sun with perhaps some shade in the heat of the afternoon. Sundews growing in full sun are more red than those in part sun. Moisture: Sundews need to be kept moist. Use soft (acidic) water and a peaty or sandy soil. Hardiness: USDA Zones 6 - 9 . Propagation: Sundews can be propagated from root cuttings and also with cuttings from fully developed leaves. Seed should be sown as soon as ripe.
Sundews are often grown in terrariums where the humidity can be kept constantly high. They mix well with various mosses, ferns, and other small wetland plants. Sundews often are displayed in plantings with Venus flytraps (Dionaea muscipula), and pitcher plants (Sarracenia), on a bed of sphagnum moss over sand.
In North America, our insectivorous plants include the pitcher plants (Darlingtonia and Sarracenia spp.), the butterworts (Pinguicula spp.), the bladderworts (Utricularia spp.), and the sundews (Drosera spp.)
In sandy, constantly seeping wet habitats, nutrients, especially nitrogen, are often in short supply. Few plants can survive in such situations, but those that have the ability to get their nutrients from animals (insects, etc.) have a distinct advantage and sometimes dominate the flora of seepage wetlands and bogs. In habitats that are not so poor in nutrients, the insectivorous plants are out-competed and generally absent.
When an insect lands on a sundew, the sticky, gland-tipped hairs slowly move, pulling the hapless prey inward where it is gradually digested and absorbed.
Steve Christman 6/10/12