Celtic Astrology and Zodiac

Druids practiced astrology around 1000 Before Common Era.
Druids were many things all together: philosophers, priests, scientists and poets... in the Celtic community.
They were trained since their childhood and had to go through the equivalent of 20 years of studies.
They are the ones that came up with the Celtic astrology. For the Druids, trees were special, they all had a spirit.
With the spirits and the moon cycles, they created a zodiac.
The Celtic Astrology is divided in 13 months with each 28 days.
Rowan: January 22 - February 18.
Ash: February 19 - March 17.
Alder: March 18 - April 14.
Willow: April 15 - May 12.
Hawthorn: May 13 - June 9.
Oak: June 10 - July 7.
Holly: July 8 - August 4.
Hazel: August 5 - September 1.
Vine: September 2 - September 29.
Ivy: September 30 - October 27.
Reed: October 28 - November 24.
Elder: November 25 - December 23.
Birch: December 24 - January 21.