Growing Tansy: A Complete Profile
By Growing Home Greens Team · August 20, 2026
Tansy is an old cottage-garden and strewing herb that modern toxicology has largely retired from use.
Rated high toxicity
NC State Extension rates it high severity. It contains thujone, may cause skin irritation or contact dermatitis on handling, and excess consumption may cause convulsions or death. Horses, cattle and humans are all listed.
Historic culinary use is documented and is not something to revive. If you grow it, grow it as an ornamental.
Restricted in several states
Prohibited or restricted in Colorado, Minnesota, Montana, Wyoming and parts of Washington, and reported invasive in Maryland, Minnesota, Idaho, Oregon, Washington, Wisconsin and Wyoming. Check your own state before planting.
Growing it
One to five feet tall on a narrow nine to eighteen inch footprint, hardy zones 3 through 8, flowering July through September in full sun to partial shade. The flat clusters of gold button flowers dry well.
Deadhead before the seed scatters, and wear gloves when cutting it back.
Source: NC State Extension Gardener Plant Toolbox, Tanacetum vulgare.
Companion planting guide for Tansy · Find your planting dates
Typically viable in USDA zones 3-8. Not sure your zone? Look it up by ZIP code.
Mature height: 1-5 ft
Method: Direct sow: Direct-sow outside. It doesn't transplant well, or doesn't need the extra time indoors.
When to plant tansy, by zone
Every zone tansy grows in. Pick your zone in the header and it will be highlighted here. Each zone links to its full page.
| Zone | Start indoors | Sow or plant out | Harvest |
|---|---|---|---|
| 3a & 3b | Not usually | May 16–May 23 | First real harvest the season after planting |
| 4a & 4b | Not usually | May 1–May 8 | First real harvest the season after planting |
| 5a & 5b | Not usually | Apr 26–May 3 | First real harvest the season after planting |
| 6a & 6b | Not usually | Apr 11–Apr 18 | First real harvest the season after planting |
| 7a & 7b | Not usually | Mar 27–Apr 3 | First real harvest the season after planting |
| 8a & 8b | Not usually | Mar 11–Mar 18 | First real harvest the season after planting |
See exact start-indoors, direct-sow, and harvest dates for your zone →
How many Tansy plants fit per square foot?
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1-5 ft.
Where to buy tansy seeds
True Leaf Market (each supplier's tansy seeds)
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See it growing
Search YouTube for "growing tansy" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
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Growing Tansy: Flat gold button flowers, high toxicity from thujone, and restricted or prohibited in several states.
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