When to plant tarragon in Portland, Oregon
February 25 – March 11
Transplant outdoors · typical Portland yearClimate basis: NOAA station Portland Kgw-tv, OR (USC00356749), 1 mi (1 km) from downtown Portland (ZCTA 97204 centroid), elevation 159 ft, on the 1991–2020 climate normals. Transplant tarragon outdoors from approximately the dates above, anchored to the median last spring 32°F freeze (February 25). One year in ten still freezes after March 21.
The Portland year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to Mar 21
Every method, with its sources
Transplant outdoors
Feb 25 – Mar 11USU Extension says to transplant French tarragon in the spring after the last frost so the tender young shoots survive, a point rule that opens a two-week planting span at the last spring freeze. Anchored to the median last spring freeze (Feb 25). Utah State University Extension · Virginia Cooperative Extension, Virginia Tech
Start seeds indoors
Not calculatedThe cited extension guides do not time an indoor seed-starting window for this crop.
Direct-sow outdoors
Not calculatedThe cited extension guides do not time direct sowing for this crop.
Fall planting
Not calculatedNo source-backed fall planting rule exists for this crop in the registry, so no fall window is calculated.
Variety assumption: Assumes French tarragon, which Virginia Cooperative Extension says can only be propagated asexually — seed-grown plants are the flavourless Russian type — so no seed-sowing window is given.
These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.
Crop rule sources (2)
- Utah State University Extension: How to Grow French Tarragon in Your Garden (accessed 2026-07-25)"Transplant French tarragon in the spring, after the last frost, to ensure the survival of tender young shoots."
- Virginia Cooperative Extension, Virginia Tech: Herb Culture and Use (Publication 426-420) (accessed 2026-07-25)"In addition, many culinary herbs, such as tarragon, can only be propagated asexually; seed-grown plants lack the oils that give them flavor."