Sage is a herb used as incense: the dried leaves of sage; several species are burned as a cleansing smoke, from the culinary sage of Europe to the white sage central to certain Indigenous North American ceremonies. In Western correspondence it is often given to Jupiter.
Material and correspondence
In the Western system of ritual correspondences it is set under Jupiter and the element of Air. Such planetary and elemental attributions belong to the Western esoteric tradition of correspondences, drawn from writers such as Agrippa and codified in the modern period by the Hermetic Order of the Golden Dawn; the material's use as incense is far older and cuts across many cultures. It is described here within that documented tradition of ritual perfume.
Two plants, and a live objection
"Sage" covers more than one species. Culinary sage, Salvia officinalis, is the Mediterranean kitchen herb; the sage most often sold and burned in North America as a bundled smudge stick is a different, unrelated plant, Salvia apiana, white sage, native to California and Baja California, and the two are not interchangeable in either use or meaning. Burning bundled white sage specifically, as opposed to burning aromatic plants in general, is a living ceremonial practice of a number of Native American nations, and commercial harvesting and sale of white sage as a consumer wellness product is a position several of those nations and Native scholars have publicly and specifically objected to, arguing that selling the ceremony apart from the land and people it belongs to amounts to dispossession rather than tribute. This is a current disagreement among living communities, not a settled matter of history, and it is presented here as such rather than resolved one way or the other.