HomeMy WebLinkAboutTansy Ragwort.pdf In bloom Leaf (L. Scott) Extensive growth in fields
Maple Ridge Noxious Weeds Program
Tansy Ragwort
(Senecio jacobaea)
Designation: Provincially Noxious
Photo: L. Scott
History:
Introduced from Eurasia, first reported in BC
in 1913.
How to Identify:
Flowers: Several many daisy‐like, bright
yellow flowers in flat‐topped clusters. The
black‐tipped bracts of the flower heads are
arranged in a single row. Plants flower from
July through September, depending on
geographic location.
Seeds: Ribbed seeds are 1 mm long with a
pappus of white hairs about 3 mm long.
Leaves: Basal leaves are stalked, 4 – 20 cm
long, and 2 – 6 cm wide. Stem leaves are
alternate, becoming progressively smaller
and stalkless moving upward. All leaves are
deeply cut, giving the plant a ragged
appearance.
Stem: Mature plants are 0.2 – 1.2 m tall. The
one to several stems are erect and are
branched near the top. First year plants do
not flower and are dense rosettes with dark
green ruffled or lobed leaves on purplish
stems.
Location: Grows on disturbed sites in
pastures, hayfields, roadsides, and
unmaintained areas in new developments.
Mistaken Identity: The leaves of common
tansy (Tanacetum vulgare), another noxious
weed, are sharply toothed, and the flowers
look like yellow buttons because the ray
flowers are absent.
The native dryland ragout (Seneca
eremophilus) resembles tansy ragwort, but
the leaf tips are pointed rather than
rounded.
Danger / Impact
Agricultural: Tansy ragwort reduces forage production of
pastures by up to 50%. Contains alkaloids that can poison
livestock, but the plant is often avoided by animals.
Ecological: Primarily a weed on agricultural land but has been
appearing on coastal clear‐cuts in BC.
Human: Trace amounts of alkaloids appear in milk and honey
produced from infested pastures, raising concerns for human
consumption of these products.
Management:
Seed production can be prevented by repeated and thorough
mowing before flowering is advanced. Plants mown after
flowering can still set seed. Small infestations can be pulled by
hand, ensuring to remove as much as the root as possible.
Some broadleaf herbicides such as triclopyr, 2, 4‐D and
dicamba, have been effective for tansy ragwort control.
Biological control is effective at reducing (but not eliminating)
populations (and is being used in the Fraser Valley).
Disposal: Make sure to properly discard all plant pieces in thick
plastic bags and transport them to a sanitary landfill site or
incinerator. Composting is not an appropriate means of
disposal as this may result in further distribution. Remember
that humans can actually spread invasive plants by taking seeds
from one place to another on clothing, tires, equipment, etc.
Restoration and Planting Alternatives:
Seed disturbed areas to perennial grasses and forbs. Manage
grazing animals to maintain perennial plant communities.
Hand‐pull plants and remove them from new infestations. Cut
plants before they go to seed.
Photo: Ministry of Agriculture and Lands
Distribution in DMR:
Small groups of plants found in a few areas; A weed for
rapid response and eradication.
Who Do you Call?
1) REPORT PROHIBITED WEEDS – Report‐A‐Weed: www.reportaweedbc.ca 1‐888‐WEEDSBC
2) DMR: 604‐467‐7363 – AND SEE: http://www.mapleridge.ca/714/Invasive‐Plant‐Species
Information and photos:
http://www.weedsbc.ca/pdf/tansy_ragwort.pdf
http://your.kingcounty.gov/dnrp/library/water‐and‐land/weeds/BMPs/tansy_ragwort‐control.pdf
http://iscmv.ca/target‐species/species‐profiles
http://www.bcinvasives.ca/publications/TIPS/Tansy_ragwort_TIPS.pdf