The Druidic Tree Calendar is based on the Robert Graves system and the Celtic lunar year of 13 months, each associated with a sacred tree. Based on your date of birth, your Birth Tree is determined — the tree ruling the period of your birth in the Ogham/Celtic calendar system. Each tree carries an Ogham letter (the ancient Celtic script carved into stone and wood), an element, a planet, a color, a sacred stone, an animal totem and a set of keywords describing temperament, strengths and challenges. The analysis covers the mythological and shamanic aspects of your tree in the Celtic tradition, practical advice for working with tree wisdom and a personalized interpretation of life themes.
Where it comes from
The tree calendar comes from Robert Graves's The White Goddess, published in 1948 — a work of poetic reconstruction in which Graves proposed that the Ogham letters formed a thirteen-month lunar calendar of trees. Scholars of Celtic studies do not accept it as historical; the Ogham tree names are genuine medieval Irish, but the calendar Graves built from them is his own. It is widely used in modern druidry and is best described as a twentieth-century system on medieval material.
How the method works
The year is divided into thirteen lunar months, each ruled by a tree, and your birth date falls in one of them. Each tree carries an Ogham letter, an element, a planet, a colour, a stone, an animal and a set of keywords describing temperament. Birch opens the year and is read for beginnings and clearing away; rowan for protection and sight; ash for connection between worlds; alder for standing firm in difficult ground; willow for the moon, intuition and grief; hawthorn for restraint and what is fenced off; oak for endurance and the turning point of the year; holly for holding the ground already won; hazel for knowledge from a source; vine and ivy for growth that clings; reed for what is hidden and searched for; elder for endings. The reading is of that tree's character and the associations attached to it.
What a reading covers
A reading gives your birth tree with its Ogham letter, element, planet, colour, stone and animal totem, the temperament and difficulties traditionally described for it, and the mythological material attached to that tree in Irish and Welsh sources.
Common questions
- Is this an authentic Celtic calendar?
- No. The tree names and Ogham letters are genuinely medieval Irish; the calendar arrangement is Graves's reconstruction from 1948 and is not supported by the historical evidence.
- Thirteen months — how does that fit the calendar year?
- Thirteen lunar months of twenty-eight days come to 364, with one day left over that Graves treated separately. The boundaries are fixed dates in the modern version rather than actual lunations.
- Is this the same as the Ogham oracle?
- They share the alphabet but not the method. The oracle draws staves at random; the calendar assigns one tree by date of birth.