cleavers (Galium aparine)
Galium agreste Wallr. var. echinospermum Wallr.
Galium aparine L. ssp. spurium (L.) Simonkai
Galium aparine L. var. echinospermum (Wallr.) Farw.
Galium aparine L. var. intermedium (Merr.) Briq.
Galium aparine L. var. minor Hook.
Galium aparine L. var. vaillantii (DC.) Koch
Galium spurium L.
Galium spurium L. var. echinospermum (Wallr.) Hayek
Galium spurium L. var. vaillantii (DC.) Gren. & Godr.
Galium spurium L. var. vaillantii (DC.) G. Beck
Galium vaillantii DC.
TAXONOMY: The currently accepted scientific name of cleavers is
Galium aparine L. No infrataxa are recognized in this review in accord-
ance with current taxonomic views. However, some systematists recog-
nize 1 or 2 varieties.
NATIVE STATUS: Native, United States; uncertain status, Canada.
The nativity of cleavers is debated. While most accept this species as na-
tive, some consider it nonnative. Still others suggest that cleavers is a na-
tive, but that subsequent introductions have occurred as well. In a litera-
ture review, it is suggested cleavers arrived in the fur of animals crossing
the Bering Strait into North America. While debate regarding the nativity
of cleavers continues, it is in all likelihood native and is considered native
in most literature.
GENERAL BOTANICAL CHARACTERISTICS:
Habit: Cleavers is an annual forb that due to its highly plastic nature can
grow as a winter or summer annual in temperate regions. Under certain
environmental conditions, cleavers may grow more like a biennial.
Cleavers has weak square stems with few branches. Weak stems give
cleavers a gangly appearance, and tangles of cleavers's scrambling stems
with nearby vegetation are inevitable. This growth form allows cleavers
a spread of up to 6 feet (1.8 m). At the stem angles are hooked hairs or
bristles that further aid in clambering and provide for plant dispersal.
Leaves: A distinct characteristic of bedstraw species (Galium spp.) is
leaves arranged in whorls. Cleavers typically displays simple linear leaves
(0.4 to 3.2 inches long (1-8 cm)) in whorls of 8. However, whorls of 6 and
7 leaves occur as well.
Flowers: Flowers are perfect cymes and clusters of 1-3 (usually 2) very
small white flowers on stalks rising from whorled leaf axils.
Fruit/Seeds: fruits are schizocarps that measure between 1-4 mm in dia-
meter, but 3-4 mm is more typical. Seeds are covered with sticky hooked
hairs. When found on dry sites, cleavers leaves measure 0.4 to 1.6 inches
(1-4 cm) long, and fruits typically range from 1.5 to 3 mm in diameter.
Roots: The cleavers root system is a shallow, branching taproot.
REGENERATION PROCESS: As an annual, cleavers reproduces sole-
ly by seed. Cleavers produces perfect flowers and is largely self-pollinat-
ing. However, some studies indicate that insects may pollinate cleavers;
in addition and, infrequently observed small bees and flower flies visiting
cleavers flowers may also do some pollination.
HABITAT TYPES: Cleavers is fairly ubiquitous. It occurs in coniferous
forests, deciduous woodlands, meadows, prairies, flood plains, disturbed
areas, abandoned fields, and cultivated crops.
SITE CHARACTERISTICS: Cleavers thrives in many natural and
disturbed areas. Shady, moist sites are preferred, but full sun sites are
tolerated with sufficient moisture . Cleavers is common on seashores of
Alaska and in riparian areas of the Grand Canyon. It is found in scrub
areas, woodlands, meadows, roadsides, and waste sites of the Gulf and
Atlantic coasts, and occupies deciduous forests, thickets, disturbed sites,
springs, limestone glades, weedy meadows, and flood plains in the Plains
States. Cleavers is also common in gardens, cultivated crops, fence lines,
barnyards, ditches, abandoned fields and homesteads throughout its range.
In natural settings, the presence of cleavers may give an indication of
natural regeneration following disturbances. Cleavers favors moist soils
and tolerates sites with moderate to poor drainage. Rich loam, heavy
organic soils with above average nitrogen and phosphorus content, and
pH values between 5.5 and 8.0.
SEASONAL DEVELOPMENT: Cleavers flowers appear from early
spring through late summer or early fall. Flower development depends
on site and climate conditions; blooming times can vary considerably.
GENERAL DISTRIBUTION: Cleavers is widely distributed in North
America. It occurs in every U.S. state except Hawaii. Cleavers is present
in parts of northern Mexico and in most Canadian provinces (not includ-
ing Labadour, Yukon and Northwest Territories).
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: Cleavers is not a major food source for
livestock or wildlife. Direct evidence of small mammal use of cleavers is
lacking. Wild turkeys, ring-necked pheasants, Canada geese, and prairie-
chickens eat cleavers seeds. However, the stiff, hooked hairs coating the
seeds may discourage predation by small birds. Several caterpillars includ-
ing the drab brown wave, common tan wave, and large lace border feed
on cleavers. Cleavers's wide distribution may explain the reason for its
diversity of practical uses. Cleavers seeds are used as a coffee substitute,
and like coffee, cleavers successfully curbs the appetite. Ripe seeds when
roasted and ground are considered a "poor man's instant coffee". A seed
extract was used to curdle milk for cheese making. The easily matted cleav-
ers stems were used as strainers to remove particles from liquids and for
mattress fillings. Bedstraw, the common name given to the Galium genus,
developed out of this mattress filling use. A red dye is made from cleavers
roots. Belgian lace makers utilized the seeds as pin heads. The Cowichan,
Native Americans of Pacific Northwest Coast, found cleavers removed
pitch when rubbed on sticky hands. Women of the Cowlitz tribe bathed
with cleavers as it was thought to make them sexually attractive.
Chippewa used cleavers as a laxative and to treat dermatitis. Native people
of the Micmac tribe used cleavers to treat gonorrhea and kidney problems.
Europeans used cleavers plant juice to treat inflamed tonsils, poisonous
insect and snake bites, earaches, liver ailments, goiters, scurvy, tumors,
and cancers. The plant was traditionally used to treat skin diseases. Herb-
alists believe that it lowers blood pressure and body temperature, use it
for cystitis. The whole plant is considered rich in vitamin C. As a pulp, it
has been used to relieve poisonous bites.
As a tea, the plant is said to have medicinal properties as a tonic, diuretic,
and laxative. In addition, the tea has been used as an anti-perspirant (by
the Chinese), and as a relief for head colds (home remedy), restlessness,
Galium spp. seed is prohibited or restricted in Connecticut, Massachusetts,
New York, and Vermont. Kentucky recognizes stickywilly as a "lesser
threat" weed species that "principally spreads and remains in disturbed
corridors, not readily invading natural areas". Cleavers appears in several
weed identification references as well. Its ability to colonize disturbed sites,
occurrence in cultivated crops, and long-distance dispersal potential are
likely reasons for its inclusion in weed literature. The Canadian provinces
of Alberta, British Columbia, Manitoba, and Saskatchewan list cleavers as
a noxious weed. Under the Canada Seeds Act, cleavers is a Class 2 "prim-
ary noxious weed seed."
Crooked Run Valley