Rural Roots Special Edition - Weeds of Distinction | Page 6

COMMON TANSY SCENTLESS CHAMOMILE
Noxious Noxious
Tanacetum Vulgare
Common Tansy is a perennial forb that thrives in
disturbed areas and well drained soils. Identifiable
by its bright yellow button-like flowers, and deeply
divided into numerous narrow, individual leaflets
with toothed edges. This plant has rhizomatous
roots and can re-grow from severed root
fragments. Common Tansy contains alkaloids
that are toxic to both humans and livestock if
consumed in large quantities.
Mechanical: Cultivation of this plant will result
in flowering stems and re-growth. Regular
mowing can reduce seed production but must
be repeated to eliminate regrowth from the root
stalk. A combination of mowing/hand cutting with
herbicide control and encouraging the growth of
the native desirable species has proven to be the
most effective method of control.
Herbicides such as Aminopyralid alone or in a
product mix or in a product mix, Metsulfuron-
methyl alone or in a product mix, and Tribrnuron-
methyl are registered for use.
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Tripleurospermun Inodorum
Scentless Chamomile can act as an annual,
biannual or a perennial. This plant grows from
fibrous roots and is established very quickly on
disturbed sites. It continually blooms, forms
seed and seeds out throughout a single growing
season. This plant can produce up to 100,000
seeds per season, which can lay dormant in the
soil for 20 years. Identifiable by its white daisy-like
flowers and alternate leaves that are very finely
dived into short segments (carrot-like).
Look alike: Oxeye Daisy, Pineapple Weed.
Mechanical: Cultivation in the late fall and early
spring will control emerging plants. Frequent
shallow tillage can exhaust the seed bank.
Mowing Scentless Chamomile can prevent seed
production; however plants will re-bloom below
cutting height. Hand pulling Infestations can
be the most effective.
Herbicides such as Aminopyralid alone or
in a product mix. Chlorsulfuron, Clopyralid
alone or in a product mix, Metsulfuron-methyl
and Tribenurin-methyl in a product mix. There
has also been a seed-head feeding weevil,
Omphalapion hookeri, and a gall midge,
Rhopalomyia tripleurospermi, released in Alberta
for biological control on Scentless Chamomile.