Celtic tree astrology, also called the Celtic tree calendar or Celtic tree zodiac, is a modern symbolic system that assigns a tree to your birth date. It borrows the tree names of the medieval Irish ogham alphabet and arranges them into roughly 13 signs across the year. Despite being sold as ancient Druid wisdom, it was devised by the poet Robert Graves in the 1940s.
A modern system built on real tree lore
Most people arrive here because a birthday quiz or a calculator told them they are a “Birch” or an “Oak,” and they want to know what that means. This page gives you that: the 13 signs, the dates, and how to find yours. It also gives you the one thing the popular sites leave out, which is a straight account of where the system actually came from.
Here is the short version, so nothing is hidden. The tree names are genuinely old. They come from the ogham alphabet, the early medieval Irish script, a real writing system known from around 400 surviving stone inscriptions. The astrology layer built on top of those names is not old. It is a twentieth-century creation.
That split is the whole story of celtic tree astrology: an authentic set of tree names, a modern personality system laid over them. The same honest line runs through our guide to the so-called Celtic runes, and it applies here too. You can enjoy your tree sign and still know what it really is.
What celtic tree astrology actually is
Celtic tree astrology runs on one simple rule. Each birth date maps to one tree “sign,” and each tree carries a personality reading, the way a sun sign does in Western astrology. Look up your dates, find your tree, and read its traits as a lens on your character.
It is almost always presented as ancient Celtic or Druidic wisdom. That part does not hold up. No ancient Irish inscription, manuscript, or law text links the ogham letters to a calendar or to birth-date personality. The tree calendar is lunar in flavor, running roughly 13 months of about 28 days, and that lunar framing was itself a design choice by the system’s modern author, not a recovered Celtic practice.
The genuinely attested seasonal markers of Celtic-speaking cultures were the four fire festivals, Samhain, Imbolc, Beltane, and Lughnasadh, not a 13-tree calendar. The one directly attested ancient Celtic calendar, the Coligny calendar found in France in 1897, is a 12-month lunisolar system inscribed in Gaulish with no tree names at all.
None of this makes the tree signs worthless. It just places them correctly. Celtic tree astrology is best understood as a modern interpretive tradition rooted in real tree names, and plenty of worthwhile traditions are modern. The honest frame is the useful one: enjoy it as a symbolic system, not as recovered ancient prophecy.
How it works: from your birth date to a tree sign
The method itself takes just three quick steps.
- Take your birth month and day.
- Match them against the 13-sign date table below.
- Read that tree’s trait blurb as a personality lens.
That is the whole mechanic. The trait readings vary from site to site because, as you will see, no single version is authoritative.
One point trips people up, so it is worth stating plainly. Your Celtic tree sign is not the same as your Western zodiac sign, and it does not replace it. Western astrology is solar, with 12 signs tied to the sun’s path through the year. The Celtic tree system is lunar, with 13 periods of roughly 28 days each.
The two systems count time differently and were built for different purposes, so your tree sign and your sun sign are separate and unrelated. Being a Gemini tells you nothing about which tree you are, and the reverse is just as true.
Free online calculators will do the lookup for you and hand back a tree in a second, which is why the “which tree are you” search is so popular. If you would rather skip the table and just get your result, you can find your Celtic birth tree by month. The full dated list is next.
The 13 tree signs at a glance
Here is the standard 13-sign scheme, the version almost every modern site reproduces. Each tree keeps its ogham letter name, its date range, and one short trait line.
| Tree (ogham name) | Dates | Trait in a line |
|---|---|---|
| Birch (Beth) | Dec 24 to Jan 20 | Driven, resilient starter |
| Rowan (Luis) | Jan 21 to Feb 17 | Visionary, idealistic thinker |
| Ash (Nion) | Feb 18 to Mar 17 | Imaginative, free, sea-drawn |
| Alder (Fearn) | Mar 18 to Apr 14 | Confident, path-finding trailblazer |
| Willow (Saille) | Apr 15 to May 12 | Intuitive, patient, watchful |
| Hawthorn (Uath) | May 13 to Jun 9 | Adaptable, curious, full of contradiction |
| Oak (Duir) | Jun 10 to Jul 7 | Confident, protective optimist |
| Holly (Tinne) | Jul 8 to Aug 4 | Capable, ambitious, generous |
| Hazel (Coll) | Aug 5 to Sep 1 | Clever, organized, knowledgeable |
| Vine (Muin) | Sep 2 to Sep 29 | Refined, changeable, discerning |
| Ivy (Gort) | Sep 30 to Oct 27 | Loyal, resilient, quietly determined |
| Reed (Ngetal) | Oct 28 to Nov 24 | Probing, secretive, truth-seeking |
| Elder (Ruis) | Nov 25 to Dec 23 | Free-spirited, restless, honest |
For the full dated breakdown and a proper description of each sign, see the full Celtic tree calendar. If you only want your own, you can find your birth tree directly.
One caveat before you commit these dates to memory. This is the common version, but the date ranges are not standardized, and some sources shift the boundaries or even the number of signs. That inconsistency is a clue to the system’s real origins, which is where we go next.
Where it really came from
The story is documented, and it is worth telling in order, because every link in the chain is modern.
The seed was planted in the nineteenth century by Edward Davies, a Welsh antiquarian. He read Ruaidhrí Ó Flaithbheartaigh’s seventeenth-century Irish history Ogygia, which mentions tree names but describes no calendar, and speculatively insinuated that a tree calendar might once have existed. There was no evidence for it. It was a guess.
The poet Robert Graves built his system on that guess. In The White Goddess (written 1946, published 1948) he took the roughly 20-letter ogham alphabet, kept 13 consonants, discarded the rest as “late additions,” and mapped the survivors onto 13 lunar months he laid out himself. To make the scheme work he folded in plants that are not trees and were never core ogham letters, notably vine and ivy, which are climbers.
The evidence against him was available at the time. R.A.S. Macalister, the leading ogham scholar of the era, personally warned Graves in correspondence that the tree-alphabet tradition could only be traced to the sixteenth century, not to antiquity, and that he should not build serious claims on it. Graves published anyway.
Later scholarship has been blunt. In 1997 the Celtic-studies historian Peter Berresford Ellis published a paper in The Astrological Journal titled ‘The Fabrication of “Celtic” Astrology,’ documenting that Graves was not a Celtic scholar and that his tree calendar has no basis in early Irish sources. What reaches you today as ancient Druid lore is, in plain terms, a modern literary invention by one gifted poet, not preserved ancient wisdom.
The genuine tradition behind the tree names
If that feels like a letdown, here is the good news: the tree names connect to something genuinely old and genuinely interesting. It just is not a zodiac.
The real meanings of the ogham letters come from the Bríatharogam, the medieval “word ogham.” These are two-word kennings, short poetic phrases that gloss each letter’s name, recorded and interpreted in texts such as the Auraicept na n-Éces, the “Scholars’ Primer.” They are the closest thing to an authentic meaning-tradition the ogham letters have.
A few examples show the texture. Oak (Dair) is glossed as “highest tree.” Hazel (Coll) is “fairest tree.” Alder (Fearn) is “vanguard of warriors.” These are vivid, and they reward study. What they never do is reference a calendar, a birth-date, or a personality reading. That machinery is entirely modern.
There is a further wrinkle worth knowing. Modern scholarship holds that only about eight of the roughly twenty ogham letter names are demonstrably trees at all, which undercuts even the medieval idea that the whole alphabet was a neat “tree alphabet,” let alone a zodiac.
If you want the authentic layer, that is where the richness lives. Start with the ogham alphabet itself, then read the real ogham letter meanings. The genuine lore holds up better than the horoscope, and it does not need to borrow a false age to be worth your time.
How to enjoy it honestly
None of this means you have to stop enjoying your tree sign. It is low-stakes, textured self-discovery that borrows real ogham imagery, and that makes it a good deal more interesting than a generic personality quiz. It works nicely for birthday content or a tree-themed gift. The only shift the honest version asks of you is small: treat it as a symbolic lens, not literal ancient prophecy.
Setting expectations also spares you some confusion. Because the calendar and personality layers were added in the twentieth century, the dates and even the number of signs are not fixed. The common scheme has 13 signs. A separate variant uses 21 trees spread across 39 shorter periods, so the same tree can recur for people born in different seasons.
That is why two calculators can hand you different answers. Neither is “official,” because neither descends from a real historical system.
So enjoy it for what it is, a modern tradition rooted in authentic tree lore. Knowing its real age costs you nothing and tells you why the sources disagree. If you want to see every sign laid out with its full date range, the full Celtic tree calendar has it.
Celtic tree astrology FAQ
Is celtic tree astrology real or ancient?
No. There is no ancient Irish or Celtic inscription, manuscript, or law text that links the ogham letters to a calendar or to birth-date personality. It is a twentieth-century creation. The ogham alphabet it borrows from is genuinely old, but the astrology built on top of those names is modern, not a recovered Druid practice.
Who invented celtic tree astrology?
The poet Robert Graves, in his book The White Goddess (written 1946, published 1948). He reworked the ogham letter names into 13 lunar-month signs he devised himself. He was building on an earlier, already unsupported speculation by the nineteenth-century Welsh antiquarian Edward Davies. Graves was a poet and mythographer, not a Celtic scholar.
How many celtic tree signs are there?
Most commonly 13, which is Graves’ scheme and the version you will meet almost everywhere. A separate, less common variant uses 21 trees across shorter periods, so some trees repeat through the year. Sources disagree on both the dates and the count, because neither version descends from a preserved historical system.
How do I find my celtic tree sign?
Match your birth month and day to the 13-sign table above, from Birch (Dec 24 to Jan 20) through Elder (Nov 25 to Dec 23). Free calculators automate the same lookup. To go straight to your result, find your birth tree by month, or check the full Celtic tree calendar for every date range.
Is my celtic tree sign the same as my zodiac sign?
No. They are separate, unrelated systems. Western astrology is solar, with 12 signs tied to the sun’s path through the year. The Celtic tree system is lunar, with 13 periods of roughly 28 days each. Your tree sign and your sun sign are calculated differently and tell you nothing about each other.