One of our commonest species. Wet sandy shores, meadows, swales, ditches, stream banks, cedar and tamarack swamps, moist forests, usually in open ground or clearings, and with a preference for calcareous sites.

Carex bebbii is usually a slender, relatively narrow leaved plant, but unusually robust individuals can rarely have leaves up to 5 mm wide. Such robust specimens may seem to resemble C. cristatella, which also can have ± compact inflorescences. However, the sheaths of even robust C. bebbii are at most slightly expanded at the apex, not loose and "baggy" near the apex as in C. cristatella. As well, the lowest perigynia in the spikes of C. bebbii are ± ascending and the spikes are clearly slightly longer than wide, while the spikes of C. cristatella, at maturity, are globular, with the lowest perigynia spreading or even ± reflexed. Superficially, C. bebbii resembles C. crawfordii which, however, has much narrower perigynia. The perigynia usually ripen July–August.