- Drosera, from the Greek, droseros
(droseros), "dewy, watery"
- rotundifolia, from the Latin, rotundus, "round, spherical"
and folius, "leaf"; hence "round leaf"
- Common Name, from the shape of the leaf
- Other common names include: Common Sundew, Dew Plant, Red Rot, Round-leaved
Sundew, herba rosellae, Youthwort, hierba de la gota,
hierba del rocío (Castellano), herba de la gota,
resplendor de la nit (Catalán), rundbladet
soldug (Dan), Ümaralehine huulhein, huulerohi, mokahein,
kõrvalusikas, putukasööja, ohatserohu, silmarohi
(Est), pyöreälehtikihokki (Fin), droséra,
rossolis à feuilles rondes, rosée du soleil, drosère,
rossolis, herbe à la rosée (Fr), Lus na Feàrnaich,
Ròs an t-Solais (Gaelic), sonnenthau rosollis,
rundblättriger sonnentau (Ger), kereklevelû harmatfû
(Hun), sóldögg (Is), rosolida
(It), rundsoldogg (Nor), rorela, orvalhinha, rorella
(Por), rocio del sol (Sp), rosièka okruholistá (Slovak),
rundsileshår, sileshår, daggört (Swe)
- Kingdom Plantae, the Plants
- Division Magnoliophyta, the Angiosperms (flowering plants)
- Class Magnoliopsida, the Dicotyledons
- Subclass Dilleniidae
- Order Nepenthales
- Family Droseraceae, the Sundews
- Genus Drosera, the Sundews
- Taxonomic Serial Number: 22017
- Also known as Drosera longifolia
- An insectivorous, short-lived herbaceous perennial of open bogs.
- Leaves a basal rosette. Blades round, depressed, and lying
flat on ground; ¼"-½" long and as wide or wider.
Upper surface of blades covered with reddish, glandular hairs tipped
with a sticky, glutinous secretion resembling a dewdrop that traps insects,
hence its name. Petioles ¾"-2" long and covered with
- Roots usually shallow (less than 2½"), consisting of
a taproot, functional for less than a year, replaced by mostly horizontal
adventitious roots with a few root hairs.
- Flower structure a one-sided raceme, with 2-15 flowers on a
2"-10" long stalk . There may be one to seven racemes per rosette.flowers
which only open in the sunshine. Flower-stems erect, slender, 2 to 6"
high, at first coiled inward bearing a simple raceme, which straightens
out as flowers expand; these are very small and white, appearing in
summer and early autumn.
- Sepals 5, 4mm-5mm
- Petals 5, white to pink; longer than sepals
- Stamens 5; shorter than petals
- Pistils of 3 styles
- Fruit a capsule with numerous small seeds.
- Seed tiny, light brown, and shiny, with fine lines; only about
- Compensates for the low available nutrients in its habitat by catching
and digesting insects. Insects are caught with the sticky glandular
leaf hairs, the leaf then folding around the prey. The hairs secrete
proteolytic enzymes which digest the insect and enable the plant to
absorb nutrients through its leaves. Insect capture is generally believed
to enhance growth and reproduction. It is significantly correlated with
total leaf number, number of new leaves formed, and total leaf area.
The benefits of insectivory may be site dependent; sundew may benefit
most from insect capture on the most nutrient-poor sites.
- This secretion is most abundant when the sun is at its height. These
hairs are very sensitive, they curve inward slowly and catch any insects
which alight on them; the fluid on the points also retains them. After
an insect has been caught, the glandular heads secrete a digestive fluid
which dissolves all that can be absorbed from the insect. It has been
noted that secretion does not take place when inorganic substances are
- Unmistakable as a Sundew; nothing else like it in the North Country.
- Distinguished from the other North Country Sundew, the Spatula Leaf
Sundew (Drosera intermedia) by the
round, rather than oblong, leaf.
- Greenland and Newfoundland to Alaska, south along the Pacific coast
to California and inland to Montana and Colorado; in the East, from
Nova Scotia south to Florida, west to the Mississippi River, and Minnesota.
- Also Europe, Asia, South Africa, and South America.
- Most often bogs, but also swamps, rotting logs, mossy crevices in
rocks, or damp sand along stream, lake, or pond margins. Generally associated
with sphagnum mosses, growing on floating sphagnum mats or hummocks.
May also grow on other moss or sedge peat soils.
- Usually sites with a high water table or high precipitation and humidity.
It requires continually moist or wet situations generally with the water
table 1"-16" below the soil surface. Flooding can be tolerated
for several weeks, but dry periods for but a very short time.
- Grows in organic acid soils low in available nutrients (nitrogen
and phosphorous, and calcium). Not found on limestone soils; high calcium
concentrations may be toxic to the plant. Reported from sites ranging
from neutral pH (7.3) to very acidic (3.2) Acidic soils with low nutrient
concentrations (nitrogen, phosphorous, or calcium) seem to be the most
- Very shade intolerant. Because it is so small, even sedges, grasses,
and small shrubs may limit light. Shaded plants may not develop a rosette
but instead have a more spindly habit.
- Adaptation to nutrient-poor conditions allows it to be very competitive
and persistent in acid wetlands. It has invaded disturbed sites in bogs
after peat mining, ditching, and burning. However, easily shaded
out if succession leads to the invasion of bogs by woody vegetation.
- Grows throughout Europe on wet heaths, moors, and sphagnum bogs,
especially in Wales.
- Frequent fire is necessary to maintain bog habitats. Fire suppression
has led to the invasion of woody species from the surrounding forest.
Frequent surface fires remove the young woody plants advancing from
bog edges. Where woody vegetation is dense and has lowered the water
table, fires can be severe and may alter the subsequent composition
of the vegetation.
- Most likely killed even by fast moving, low-severity fires. However,
fires in bogs are generally patchy and sundew probably survives in unburned
microsites. Colonizes recently burned peat surfaces.
- Trees: Balsam Fir (Abies
balsamea), Red Maple (Acer
rubrum), Paper Birch (Betula
papyrifera), Tamarack (Larix
laricina), White Spruce (Picea
glauca), Black Spruce (Picea
mariana), Jack Pine (Pinus
banksiana), Balsam Poplar (Populus
balsamifera), Quaking Aspen (Populus
tremuloides), White Cedar (Thuja
occidentalis), Eastern Hemlock (Tsuga canadensis)
- Shrubs: Bog Rosemary (Andromeda
glaucophyllum), Leatherleaf (Chamaedaphne
calyculata), Bog Laurel (Kalmia
polifolia), Labrador Tea (Ledum
groenlandicum), Willows (Salix spp.), Blueberries (Vaccinium
angustifolia, Vaccinium myrtiloides
), Small Cranberry (Vaccinium
- Herbs: Bluejoint Reedgrass (Calamagrostis
canadensis), Sedges (Carex spp.), Sheathed Cottonsedge
Buckbean (Menyanthes trifoliata),
Pitcher Plant (Sarracenia purpurea),
- Ground Covers: Aulacomnium palustre, Schreber's Feathermoss
Polytrichum juniperinum, Sphagnum Mosses (Sphagnum spp.)
- Insects: May be an important food source for bog-dwelling ants.
Ants are opportunistic predators of insects trapped in the leaves, scavenging
up to 2/3 of the prey caught by the plant.
- Leaves can curdle milk and were used in Sweden to make cheese.
- Fresh leaves have also been used to treat warts.
- Has been used as a remedy for respiratory ailments.
- Early herbalists believed that the 'dew' on the sundew leaves, which
persisted even in the hottest sun (hence the name!) possessed the property
to endow longevity and youthfulness to those who drank it.
- Sundews (Drosera spp.) generally survive better than other
carnivorous plants and can naturally invade disturbed bog sites where
other vegetation has been removed, such as after roadside ditching or
- Contains an antibiotic effective against Streptococcus, Staphylococcus,
and Pneumococcus bacteria.
- Clearing and drainage of peat bogs or swamps for peat mining, millpond
construction, access to timber, and agricultural purposes have resulted
in the decline of habitat by altering site conditions in many areas.
Drainage also has an indirect negative effect by diminishing the numbers
of prey that have aquatic larval stages.
- Insectivorous plants may add to the nutrient pool on the nutrient-deficient
sites where they most often grow.
- Reproduces vegetatively or by seed.
- Vegetative reproduction takes place when leaf buds form plantlets,
or when axillary buds below the rosette form a secondary rosette. As
the stem decays, the two separate.
- Cross pollinated by wind or insects when flowers are open during
the day; self-pollination may take place as flowers close in the evening.
- Fruits often persist unopened, and seeds are released when the fruit
rots. The fusiform seeds are 0.06"-0.07" (1.5-1.8 mm) long
and 0.008" (0.2 mm) wide and have an inflated testa. Air trapped
in the testa makes the seed buoyant and capable of floating for days
on water surfaces. Seeds may be carried some distance with snowmelt
- Plants flower in their first summer and every year thereafter, generally
from June to September. Flowers open one per day, starting from the
bottom of the inflorescence. Seed dispersal begins in July and most
seeds fall before winter.
- By seed, following cold stratification.
- Root division most successful method
- Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
- Cultural Requirements
- Sun full
- Soil moist, very acidic, rich in peat moss or sphagnum moss, with
a pH of 4.0 to 5.0.
- Fertilization not recommended. Sundew does not respond positively
to fertilization and burns easily.
- In a bog garden, spreads rapidly to form a natural carpet.
- Set nursery plants so they rest just on the surface of the ground;
the roots will reach down for the moisture they need. Propagate additional
plants by root division or from seeds. To guarantee sufficient moisture
for seedlings, plant the seeds in a pot that is set into a dish kept
filled with water. Osmosis will keep the surface soil damp. Given a
nearly natural environment, will also reproduce itself readily from
- Available by mail order from specialty suppliers.
Last updated on
26 February, 2004