My leaves are serrated, long, and dark green,
topped with bright yellow buttons that are easily seen.
Like many invasives, I’m toxic to eat
and considered noxious in parts of BC.
I Spy in the Sea to Sky…
This plant is native to Europe, and was transported to North America for ornamental and medicinal purposes during the 17th century. Can you guess what it is?
It’s Common Tansy (Tanacetum vulgare)! It flowers from July to September and produces seeds from August to October. It thrives in dry areas with full sun and well-drained, fertile soils. It is often found in newly-disturbed sites, along river banks, in pastures, or along roadsides. In the Sea to Sky, Common Tansy is a widespread species that is beyond landscape-level control. The goal is to strategically control the spread of Common Tansy, as per the SSISC priority invasive plant species list.
Common Tansy is one of the species featured in our Invader Eliminator kit.
Photo credit: Kalenna Olynyk
Common Tansy can be easily identified by several distinctive features:
- A perennial forb that can grow up to 1.8m tall (that’s as tall as a person!)
- Button-like, yellow flowers with no rays.
- Flowers that grow in dense, flat-topped clusters at the top of the stems. One plant can have 20 – 200 flower heads.
- Fern-like and deeply lobed leaves.
Does Common Tansy have lookalikes?
Tansy Ragwort (Senecio jacobea) is an invasive lookalike with a similar name, which can cause confusion.
Although both species have bright yellow flowers, Tansy Ragwort has daisy-like flowers, while Common Tansy has flowers that lack rays.
Additionally, the leaves of Tansy Ragwort are deeply cut and lobed, while Common Tansy has fern-like leaves.
Be careful – both species can be toxic to humans and livestock if consumed!
Why is Common Tansy such a concern in the Sea to Sky?
Common Tansy is an aggressive spreader with no natural predators in our area. It reproduces both by seed and vegetatively, from roots and creeping rhizomes. Common Tansy can also re-grow from root fragments that have been broken off. One plant can produce up to 50,000 seeds in a season, and the seeds are viable in the soil for up to 25 years, allowing Common Tansy to build a robust seed bank!
This species outcompetes native species and displaces desirable forage in pastures. It is toxic to humans and livestock, and when consumed by dairy cows it can cause bitter, unpleasant-tasting milk.
Please visit its species profile page to find out how to help.
I Spy in the Sea to Sky Contest
Guess the invasive species in our I Spy in the Sea to Sky weekly social media post, June through August, to enter our giveaway.
At the end of each month, one lucky commenter will win a native wildflower seed mix packet! Follow us and comment on social media to participate!
CONTEST RULES:
- Comment your guess (common or species name) on the social media post (on Instagram or Facebook) to enter. Only correct guesses will qualify you for the giveaway.
- One entry per person per post.
- Anyone can play, but only Sea to Sky region residents can win.
- Entries will close at 11:59 PM PST on August 31st, 2024.
- Winners will be announced in the first week of September in an Instagram story AND contacted directly via their platform of entry.
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