BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Urtica dioica | Stinging Nettle 



GENERAL BOTANICAL CHARACTERISTICS : 
Stinging nettle is an erect, perennial, rhizomatous forb which forms
dense clonal patches.  Stout stems grow 3.3 to 6.6 feet (1-2 m) tall.
Leaves, stems, and flowers are sparsely to moderately covered with
stinging hairs.  Two subspecies, American stinging nettle and hoary
nettle, are native; the third subspecies in North America, European
stinging nettle, was introduced in the mid-1800's.  American stinging
nettle and hoary nettle are predominantly monoecious whereas European
stinging nettle is typically dioecious.  The fruit is an achene [1,51].
Stinging nettle has both epigeal and shallow subterranean rhizomes [35].


RAUNKIAER LIFE FORM : 
   Hemicryptophyte


REGENERATION PROCESSES : 
Stinging nettle reproduces vegetatively and by seed.

Stinging nettle produces abundant seed.  Plants growing in the shade
produce approximately 500 to 5,000 seeds per shoot and plants growing in
full sunlight produce 10,000 to 20,000 seeds per shoot.  Seeds remain on
the plant until frost when they fall to the ground.  Seeds are not
dormant and can germinate 5 to 10 days after maturity [1].  

Buried stinging nettle seeds persist an undetermined length of time in
the seedbank [7,26,33,34,44].  Stinging nettle seedlings emerged from
unflooded substrate samples collected from the Delta Marsh, Manitoba
[33].  Stinging nettle seeds, mostly buried less than 2 inches (5 cm)
deep, occurred in the seedbanks of three forest communities in Idaho
[26].  Stinging nettle seedlings emerged from soil samples collected
from a ponderosa pine (Pinus ponderosa)/common snowberry (Symphoricarpos
albus) habitat type in Washington.  April collections contained 48
stinging nettle seeds per square foot (533/sq m) and October collections
contained 6 seeds per square foot (67/sq m).  Most stinging nettle seeds
were buried less than 4 inches (10 cm) deep, but some were present to 10
inches (25 cm) [34].  Stinging nettle seeds have germinated in the
greenhouse after 10 years of storage [1].

Stinging nettle spreads and reproduces vegetatively by rhizomes.
Seedlings initiate vegetative spread in the first growing season.  A
rhizome planted in late summer can spread into an 8.2 foot (2.5 m)
diameter area by the following year [1].

Stinging nettle has a strong shoot thrust.  The ability to generate
mechanical force enables the plant to extend its shoots vertically into
dominant aerial positions [6].


SITE CHARACTERISTICS : 
Stinging nettle occurs in moist sites along streams, coulees, and
ditches, on mountain slopes, in woodland clearings, and in disturbed
areas.  Stinging nettle generally grows on deep, rich soils [1,51].
American stinging nettle occurs from sea level to subalpine elevations.
Hoary nettle occurs from sea level to 10,000 feet (3,000 m) elevation in
the southern part of its range and from 2,300 to 6,600 feet (700-2,000
m) elevation in the northern part of its range [51].  Stinging nettle
persists in northern climates, spreading vegetatively rather than by
seed [40].

Stinging nettle occurs both in wetlands and in uplands.  It is a
facultative wetland species [36].  Stinging nettle is present in the
seasonally flooded emergent zone of oxbow lakes along the Connecticut
River [22].  Persistent flooding kills stinging nettle [20].


SUCCESSIONAL STATUS : 
Stinging nettle is probably intermediate in shade tolerance.  It occurs
and produces seed in shady habitats but produces more seed in full sun
[1].

Stinging nettle establishes colonies from which other plants are
virtually excluded.  Competition from grass may limit the spread of
stinging nettle clones [1]

Stinging nettle invades disturbed sites.  It invades forest plantations
in Great Britain when bracken fern (Pteridium aquilinum) is artificially
removed [5].  Stinging nettle colonizes wetland sites when water levels
drop [20,33].  It is an increaser on periodically flooded areas along
Idaho streams [37].


SEASONAL DEVELOPMENT : 
Stinging nettle sends new shoots up each year from perennating buds on
rhizomes.  Maximum root development occurs in the spring prior to
flowering.  American stinging nettle flowers from late May to October,
European stinging nettle flowers from June to October, and hoary nettle
flowers from July to October.  In northern areas, flowering is condensed
into a shorter time period, ending in late August [1,51].

Related categories for Species: Urtica dioica | Stinging Nettle