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Date Published: January 20, 2003
Hedge-nettle
is a perennial weed found in areas of poor drainage.
It grows up to 100 cm in height forming dense clumps.
The leaves are opposite, stalkless or occurring on short
petioles. They are lanceolate to elliptic in shape,
up to 15 cm in length with serrate edges and a pointed
tip. Both surfaces are hairy and have a deep green colour.
Stems are square in cross section, erect, branched and
covered with bristly hairs. Flowers are rose-purple
in colour, mottled with light and dark tones, producing
a whorl in the axils of the upper leaves. Individual
flowers have a two-lobed upper lip and a three-lobed
lower lip and are up to 1.5 cm long. There are usually
six flowers to a whorl. Several whorls near the top
of the stem form the inflorescence which may be up to
25 cm long.
Life Cycle
Hedge-nettle is perennial, spreading by rhizome
and seed. Flowering occurs from late June to September
with each flower producing four dark brown seeds.
Seeds drop close to the parent plant and may move
by water or wildlife. Rhizomes spread in all directions
from the parent plant. Stems arise from the upturned
ends of rhizomes, producing dense clumps. Plants overwinter
as rhizomes, which are whitish, often much branched
with thick elongated brittle tubers.
Habitat
Hedge-nettle prefers poorly drained sites. It can
be found along margins of watercourses, roadsides,
cultivated fields and waste places. Collections have
been made throughout the province.
Effects
 Hedge-nettle
can be a serious problem due to its competitive ability
and tolerance of management practices. Plants are
easily spread by seed and through cultivation of the
roots. It is extremely competitive and difficult to
control. Livestock may refuse to eat the plant either
green or in hay due to its bristles and unpleasant
taste.
There are 32 species of Stachys occurring in North
America, with approximately 25 native and seven introduced
species forming a large complex. Native and introduced
species are differentiated by chromosome number and
morphology. There is no evidence that the native forms
are weedy.
Other common names include marsh hedge-nettle, woundwort,
roughweed, clown's heal and dead nettle.
Control
Hedge-nettle is a deep rooted perennial which is
very difficult to control. Repeated cultivation may
help deplete root reserves and prevent seed production.
Care should be taken to wash machinery to remove seed
or rhizome segments before leaving infested fields.
Herbicides have been found to have little effect
on hedge-nettle. Summer fallow, utilizing repeat applications
of glyphosate followed by cultivation throughout the
growing season, may provide some control. For further
information or herbicide application rates, consult
your weed inspector or the most recent Guide to Weed
Control (Publication 75).
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