Tree pollen: spring's opening act, in a fixed order
Trees don't all pollinate at once — they take turns, and the order barely changes from year to year. What changes is the start date: late January along the Gulf, closer to April at the Canadian border. Mild springs pull everything earlier.
The batting order
First out are the winter and late-winter trees: the junipers and cedars, elm, and the maples — often before anything looks like spring. Alder plays that early role in the Northwest, and in a few desert cities it's planted mulberry that opens the season. Then the heavy hitters: birch across the northern half of the country and oak nearly everywhere, usually the biggest pollen weeks of the whole year. Pine finishes late — its yellow dust is the most visible pollen of all, though it bothers far fewer people than oak or birch.
Typical windows by region
| Region | Tree season overall | Leading trees | States |
|---|---|---|---|
| Northeast | March to June | Maple, Birch | CT , ME , MA , NH , NJ , NY , PA , RI , VT |
| Mid-Atlantic | March to June | Oak, Maple | DE , DC , MD , VA , WV |
| Southeast | January to May | Oak, Pine | AL , GA , KY , NC , SC , TN |
| Florida | December to April | Oak (live oak), Pine | FL |
| Gulf South | January to May | Oak, Pine | AR , LA , MS |
| Midwest | February to May | Oak, Maple | IL , IN , IA , MO , OH |
| Upper Midwest | March to June | Birch, Oak | MI , MN , WI |
| Plains | February to May | Eastern red cedar, Elm | KS , NE , ND , OK , SD |
| Texas | December to May | Mountain cedar (Ashe juniper), Oak (live oak) | TX |
| Desert Southwest | February to June | Juniper, Mulberry | AZ , NV , NM |
| Mountain West | March to June | Juniper, Cottonwood and aspen | CO , ID , MT , UT , WY |
| Pacific Northwest | February to May | Alder, Birch | OR , WA |
| California | January to June | Oak, Cypress and juniper | CA |
| Alaska | April to June | Birch, Alder | AK |
| Hawai'i | March to October | Kiawe (mesquite) | HI |
The Texas row wraps around the new year — that's cedar fever, the December–February mountain cedar season.
Common questions
When does tree pollen season start?
In the South, the first trees open in late January and February; across the North, the season gets going in March or April. The order is remarkably consistent — elms, maples, and junipers lead, birch and oak follow, pine finishes.
When does tree pollen season end?
Most of the country is done by late May or June, when the last of the oak and pine finishes. The big exception runs the other way: Texas mountain cedar opens a second front in December.
Season windows come from university extension and aerobiology research, reviewed August 2026. State pages carry their sources.