Samhain (pronounced approximately SAH-win in Irish, or SAH-ven in Scots Gaelic) falls on October 31 and is the most significant of the four Celtic fire festivals in the folk calendar. It marks the end of the harvest season and the beginning of winter: the dark half of the year in the Celtic reckoning, when the boundary between the human world and the otherworld was considered at its most permeable, and when the ancestors were understood to be close enough to be honored and communicated with.
In the contemporary world, this tradition survives in heavily transformed form as Halloween. But the original practice was rich with plant knowledge, and the herbs associated with this threshold time are worth knowing.
Elder: The Threshold Tree
The elder tree (Sambucus nigra) has a more complex and ambivalent relationship with Samhain than any other plant. It is associated in various Northern and Western European traditions with the passage between the living and the dead: elder planted near graves, elder branches placed at thresholds to mark and protect the boundary between worlds. In some Scandinavian traditions, burning elder wood was deeply taboo. In Irish tradition, the elder was associated with the sidhe (fairy mounds) and with the threshold of the otherworld.
The elder’s association with both healing and with death is not contradictory in the traditional worldview: the boundary between them was not absolute, and the plants that belonged to the threshold belonged to both sides of it simultaneously.
Mugwort: The Ancestor Herb
Mugwort (Artemisia vulgaris) is the herb of transitions and of the dreaming mind, and at Samhain these qualities converge. Burned as incense or placed under the pillow at this time, it has a long tradition as a facilitator of communication with the dead in the dream state and in altered states accessed through smoke and ceremony. This is the deepest and oldest use of the herb, predating any modern understanding of its chemistry.
Yew (Taxus baccata): The Tree of Death and Rebirth
The yew is not an herbal medicine in the conventional sense (it is highly toxic), but it is one of the most significant Samhain plants in the British and Irish tradition. Yew trees grow in ancient churchyards across Britain and Ireland, often far older than the churches themselves, their association with the sacred site predating the Christian layer. The yew is the tree of death, of the extreme longevity that outlasts death, and of the promise of rebirth. It is not used as medicine but as a symbol and a presence at the threshold.
Hawthorn: The Gate
As at Beltane, the hawthorn is the gatepost herb of the threshold festivals. At Samhain, hawthorn’s protective and boundary-keeping qualities are particularly relevant. This is the time to make protective preparations from hawthorn, to acknowledge the plant’s role as guardian of the threshold, and to work with it both physically and ceremonially. The Herbalist Codex app holds full profiles on all these threshold plants with their seasonal folk and ceremonial contexts.