The Tree Calendar
There are thirteen moons in the Tree Calendar. Because the lunar cycle doesn’t line up perfectly with the solar calendar, exact dates cannot be given for the correspondence of the Tree Calendar with the commonly-used Gregorian, or Christian, calendar, which is solar in origin. This is because those dates are always changing relative to the solar calendar.
The Black Mountain Druid Order’s year of 13 moons is similar to the 13-moon lunar cycle observed by many non-Christian peoples throughout the world. Since our lunar calendar doesn’t align perfectly with the more common solar calendar, it takes approximately 19 years for the cycles to match up again.
The Greeks reconciled the solar year with the lunar year in something called the Metonic Cycle. Another Greek name for the Metonic Cycle is the Enneadecaeteris, which means “nineteen” in Greek, and the cycle is thus named because it takes approximately 19 years for the solar cycle and the lunar cycle to re-synchronize.
Coincidentally, Caesar stated in The Gallic Wars that Druids studied for 20 years, so if an ancient Druid served an apprenticeship for a year and a day, and then studied for 19 more years (or the period of one Metonic Cycle), he or she would have studied for a period of 20 years altogether before the Celtic lunar calendar re-aligned with the Roman solar calendar. So if, for example, a Dedicant began to study on the first full moon after the winter solstice, and studied for 19 years, then the next full moon after the winter solstice would be on the same day that the Dedicant began the path. It’s an interesting coincidence that this period of study so closely matched Caesar’s 20-year period.
The Tree Calendar consists of thirteen months named after trees. These trees also correspond to letters of the Celtic ogham alphabet.
The origins of the Tree Calendar are somewhat controversial. Robert Graves created the earliest known complete version in his book, The White Goddess. Graves claimed that his derivation of the Celtic Tree Calendar had its origins in ancient Druidic and Bardic traditions. He claimed to have uncovered a secret code hidden in the poetry and prose of the bards of the British Isles to demonstrate this claim.
Many scholars doubt this.
I prefer to think that the origins of the calendar are irrelevant as long as it has utility for us now. Many Pagans throughout the world use Graves’s version of the calendar today because of its elegance and utility, and our Order uses it for these reasons as well.
In the following section, the dates for each lunar tree month are approximate. In the Black Mountain Druid Order, we use 13 months of 28 days each to form our calendar. The first month, Birch Moon, begins after the winter solstice. While many Pagan traditions celebrate their New Year on October 31st, in this system, the winter solstice marks the beginning of the year because it represents the rebirth of the sun.
Each month in the Graves system is 28 days. Since we use months of 28 days as a matter of convenience, our months don’t line up perfectly with the lunar cycle, but they’re close enough for our purposes. With 13 months of 28 days each, we have a total of 364 days. The leftover day (marking our ‘year and a day’ period) is a holy day dedicated to Mistletoe. In leap years, we have two days dedicated to Mistletoe. If you are born on a Mistletoe Day, you have the potential to be a powerful healer.
Each month of the Tree Calendar is associated with a tree or other plant. A Celtic horoscope can be constructed by listing the properties of each tree of the Tree Calendar. The tree (or plant) associated with your birth month is your birth tree.
One of the exercises for the Foundational Druidry course of the Black Mountain Druid Order is to spend a year and a day learning about a tree or plant. Traditionally, you would spend this time period in learning about your birth tree, but for those living in urban or suburban environments, finding a birth tree can be challenging. This is further complicated by the fact that our tree horoscope uses plants native to the Pacific Northwest region of the United States. If you live in another location, you may have to substitute local varieties of plants for your own tree calendar.
If you are fortunate enough to have access to a birth tree, you may wish to use it for your period of study. If not, you may select another tree that seems to call to you.
It may also be that when you find your birth tree, it doesn’t quite resonate with you. That’s okay too. Many Pagans and Druids believe in reincarnation, and it would be arbitrary to focus on the date of your birth in this life if you have lived multiple lives before this one. If you find that your birth tree doesn’t really fit you, then select one that you feel more comfortable with.
Once you’ve found a tree that you’re ready to work with, you’ll need to actually find one of these trees near your home. This tree should be located in a place that would make it convenient to visit at least once a day. You may be fortunate enough to have such a tree in your backyard. If not, perhaps you can find one in a local park.
The names, aspects, and qualities of each moon are listed below. Once you’ve found your birth tree, consult the list below to see what your birth month says about you.
Tree Months
Birch Moon (December 24th – January 20th)
Aspect: Feminine
This is a moon of beginnings, purification and inception. The white of the birch’s bark symbolizes purity. This month also symbolizes the protection of children. Birch people are creative and compassionate. Birch people have a firm inner resolve, and lend strength to those around them. Birches are quietly determined, often working for change behind the scenes. Common sense and practical, clear solutions to problems are strengths for birch people.
Rowan Moon (January 21st – February 17th)
Aspect: Masculine
The wood of the rowan, or mountain ash, is often used for making wands and tools of divination. This is the moon of shamans and seers. Rowan people are associated with personal empowerment, healing, and vision. Rowan people have a keen sense of intuition. This powerful intuition is often used to protect self and others. Their ability to see the future often sets them apart from others. They sometimes seem to live in two worlds at once.
Ash Moon (February 18th – March 17th)
Aspect: Feminine
Ash is another popular wood for crafting magic tools. The feminine energy of the ash is associated with water spirits and the powers of water. Ash people are associated with prosperity, protection, and the healing arts. Ash people have a special ability to see the connections in the web of life. They are natural empaths, and share the pains and joys of others. This makes them very compassionate people.
Alder Moon (March 18th – April 14th)
Aspect: Masculine
Alder people are practical people. They focus on solutions. They are dutiful, and they are good teachers. Alder people are usually quite intelligent, and the power of weather magic is associated with this moon. They also love to fight for what’s right, and expend a great deal of energy in pursuing justice. They can sometimes dissipate energy needlessly by getting involved in frivolous debates.
Willow Moon (April 15th – May 12th)
Aspect: Feminine
The Willow Moon is known as the Witches’ Moon. It is associated with fertility and balance. Willow people are romantic and well-rounded. The Willow is associated with the moon in all her phases, and this means that Willow people are driven more by instinct than intellect. If you are a Willow, pay attention to your dreams, and let them guide you.
Hawthorn Moon (May 13th – June 9th)
Aspect: Masculine
People of the hawthorn are people capable of self-restraint. This moon is associated with peace, prosperity and binding magic. It is a sign of both fertility and death. Hawthorn deals with the necessity of change and transition. If you are a hawthorn, your motto is, “This too shall pass.”
Oak Moon (June 10th – July 7th)
Aspect: Masculine
Oak people are strong, wise and secure. People born under this moon are true and faithful. It is associated with the energy of the bear. If you are an Oak, you are concerned with strength of character, and your word is your bond. You are able to endure, but direct your energies wisely lest you unintentionally harm others in your zeal.
Holly Moon (July 8th – August 4th)
Aspect: Feminine
This moon is associated with the powers of protection. Holly people also have the gift of divination, and they are protectors of the animals. The Holly Moon is also associated with the powers of sex magic. Holly people have a deep connection to the Earth, and they have a generous spirit that commands the respect and admiration of others.
Hazel Moon (August 5th – September 1st)
Aspect: Feminine
This is the Moon of the wise. It is associated with the wisdom of the elders. People of the hazel are said to be good at spirit contact, and at manifesting their desires. If you are a Hazel, the gift of persuasion is yours. You have the ability to help others to see things your way, and to resolve conflicts. Moderate this gift by only giving advice when it has been asked for!
Vine Moon (September 2nd – September 29th)
Aspect: Androgynous
Vine people are people who know how to celebrate! This moon is sacred to the Goddess Brighid, and is associated with spirituality, dream magic, and inspiration. vine people are courageous people. They are also very sociable, and have the gift of reading the thoughts and emotions of others. If you are a vine, you are able to restore balance to most situations by smoothing over ruffled feathers and finding a common solution.
Ivy Moon (September 30th – October 27th)
Aspect: Masculine
Ivy people are resilient and adaptive people. They thrive in most situations. They are also very cooperative people, and natural peacemakers. If you are an ivy, you have a talent for advancing your own personal agenda. Moderate this gift by being considerate of others when advancing your personal plans.
Reed Moon (October 28th – November 23rd)
Aspect: Feminine
The reed energy is associated with hearth and home. Reed people are protectors of family and speakers of truth. They keep the home fires burning. They often have hidden secret strengths that even they may not be aware of. They may also have secret motivations. If you are a reed, use your ability to figure things out wisely, and don’t overstep your boundaries.
Elder Moon (November 24th – December 23rd)
Aspect: Masculine
Elder people are good at banishing negative energies. This is their power of healing. This moon is also associated with the power of reincarnation and rebirth. It is a moon of completeness. Elders are able to thrive and prosper even in adverse conditions. This is because they have lived many lives, and they carry bits of wisdom from former lives into this life.
Day(s) of Mistletoe – The ‘make-up’ day(s) after the Elder Moon
Aspect: Neutral
The Druids referred to mistletoe as “All Heal” because they believed it to be able to cure virtually anything. Mistletoe people have the gift of healing and are the most powerful of all healers. Those born on a Mistletoe Day tend to be doctors, nurses, herbalists, therapists, or counselors. Since mistletoe is also associated with fertility, Mistletoe people tend to have success at romantic relationships and are generally good with children. Mistletoe people should guard against a natural tendency to be dismissive once spurned.
The Tree Horoscope | Ogham Chart | Ogham for Divination | Your Birth Tree