Trees and the calendar
Celtic zodiac signs: the tree calendar
The thirteen trees of the “Celtic zodiac”, their dates, and the surprising 20th-century origin of the system.
| Tree | Ogham letter | Dates |
|---|---|---|
| Birch | Beith | Dec 24 – Jan 20 |
| Rowan | Luis | Jan 21 – Feb 17 |
| Ash | Nion | Feb 18 – Mar 17 |
| Alder | Fearn | Mar 18 – Apr 14 |
| Willow | Saille | Apr 15 – May 12 |
| Hawthorn | Uath | May 13 – Jun 9 |
| Oak | Duir | Jun 10 – Jul 7 |
| Holly | Tinne | Jul 8 – Aug 4 |
| Hazel | Coll | Aug 5 – Sep 1 |
| Vine | Muin | Sep 2 – Sep 29 |
| Ivy | Gort | Sep 30 – Oct 27 |
| Reed | Ngetal | Oct 28 – Nov 24 |
| Elder | Ruis | Nov 25 – Dec 23 |
Where it comes from
The tree calendar comes from the poet Robert Graves, who in The White Goddess (1948) proposed that the letters of the Ogham alphabet, many named after trees, formed an ancient calendar of thirteen 28-day months. Scholars of early Irish reject this: there is no evidence that the Celts or druids used a tree calendar or a zodiac.
What the Celts really used
The best evidence for an actual Celtic calendar is the Coligny calendar, a bronze tablet found in 1897 near Coligny in eastern France and dated to the 2nd century CE. It records a Gaulish lunisolar calendar of 62 consecutive months over five years, with months marked as good (MAT) or not good (ANM). It has nothing to do with trees or a zodiac. Irish and Welsh sources also record the great seasonal festivals of Samhain, Imbolc, Beltane and Lughnasadh.
The Ogham letters behind the trees
Medieval Irish scholars gave many Ogham letters tree names (beith, birch; luis, often read as rowan; fearn, alder; saille, willow; duir, oak; coll, hazel), though several identifications are uncertain. Graves took the letter order, chose thirteen consonants and assigned each a 28-day month starting at the winter solstice.
Celtic zodiac signs and meanings today
The tree calendar is popular in modern paganism and as a nature-based alternative to the zodiac. If you use it, enjoy it as a 20th-century creation rather than an ancient druidic tradition.
Frequently asked questions
What is my Celtic zodiac sign?
Find your birthday in the table above. December 23 belongs to Elder; December 24 starts Birch.
Sources
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