I think people can connect with the Celtic Tree Calendar and using it as a Zodiac type of theme. I know Ogham is a bit of the same type of information and using Ogham for divination and not just a language or alphabet is something that is done. I mentioned it was new from information about Robert Graves, but before then it was probably more territory based as far as the Celtic tribes across the pond. (I hope that makes sense)
- The two following links are from the Weekly Witchy Challenge: Sacred Trees. The first link is part of a catch up challenge. The second link goes to that particular challenge, where there is also other entries regarding the Celtic Tree(s) Calendar.
→ Robert Graves: Celtic Tree Calendar
→ Robert Graves: Celtic Trees
I wouldn’t say it’s completely new to the craft, in some way the druids and Celts, Irish, UK area & territories, among other territories probably had some kind of associations with the Celtic Trees & Ogham. Robert Graves did bring it to a more common practice within the craft implementing it more widespread than the celts and their areas using them in their culture. (Another word salad… Sorry 
)