When to plant hyssop in Iowa
Iowa spans USDA zones 5a–6a, so the right time to plant hyssop shifts by weeks across the state. The window to transplant seedlings outdoors runs from about April 12 in Fort Madison to May 1 in Spencer — below are local dates for 42 cities, each computed from its own frost dates.
| City | Zone | Last frost | First frost | Transplant out |
|---|---|---|---|---|
| Des Moines | 5b | April 18 | October 20 | April 18 – May 2 |
| Cedar Rapids | 5b | April 27 | October 11 | April 27 – May 11 |
| Davenport | 5b | April 19 | October 22 | April 19 – May 3 |
| Sioux City | 5a | April 29 | October 7 | April 29 – May 13 |
| Iowa City | 5b | April 21 | October 18 | April 21 – May 5 |
| Ankeny | 5b | April 23 | October 15 | April 23 – May 7 |
| West Des Moines | 5b | April 18 | October 20 | April 18 – May 2 |
| Ames | 5b | April 26 | October 8 | April 26 – May 10 |
Hyssop in Iowa: FAQ
When can I plant hyssop in Iowa?
Across Iowa, the time to transplant hyssop spans roughly April 12 in Fort Madison to May 1 in Spencer, each following that city's local frost dates.
Does the hyssop planting date vary across Iowa?
Yes. Iowa publishes 42 cities with their own frost dates, so the right hyssop planting window shifts by weeks between the warmest and coldest parts of the state — use your city's page for the exact dates.
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