I also thought of Enya's song. Flora's Secret, which sums up the passing of winter…
"Some they know as passion
Some as freedom
Some they know as love
And the way it leaves them
Summer snowflake*
For a season
When the sky above is blue
When the sky above is blue."
* Summer snowflake or "white violet", is a bulbous fragrant flower that blooms in early spring in the far northern countries. (See attachment)
Perhaps instead of Halloween
, we should all celebrate the colourful the blooming of the purple Jacaranda Trees, like they do in Brisbane, Grafton NSW, Pretoria in South Africa, etc. (though those poor flowers in Grafton on the NSW northern coast recently were mostly destroyed by the rainfall!)
Give them young kiddies something that mark the southern seasons, and not just copy those northerners unrelated festivities - which have little meaning to us. 
Note: As to the mythology legends of Flora, which is the name of the eighth discovered asteroid in 1847. There is a good summary, that appears on the webpage http://homepage.mac.com/andjames/PageFlora000.htm . The mythology is discussed in the latter half of the webpage
Hope this is of interest!