Early September can look and feel a lot like summer around New Glarus. The afternoons can still be warm, the trees remain overwhelmingly green and frost is a distant concern. But nearly everywhere outside, the natural world has already begun changing gears.

The most obvious evidence may be along roadsides, prairie remnants and open fields, where September belongs to yellow and purple. Goldenrods are flowering alongside asters and other late-summer blooms, providing some of the season’s richest color — and some of its most important remaining nectar sources. The University of Wisconsin-Madison Arboretum describes September simply as “goldenrod and aster season,” with numerous species blooming during the month.

The grasses are changing, too. Big bluestem, recognizable by seed heads that resemble a turkey’s foot, is reaching full height along with Indian grass and little bluestem. As September progresses, some of those deep summer greens will give way to bronze, copper, amber and purple.

And although nobody should mistake a few red leaves for peak fall color, the first previews are becoming easier to find. Sumac along rural roads and fencerows is among the earliest to turn crimson, while Virginia creeper can add flashes of red against otherwise green trees. The main show is still well ahead: Wisconsin’s 2026 Fall Color Report currently forecasts peak color in Green County during the fourth week of October.