So, how many blossoms can you  actually get.

Well if you take the teaser quest that's 1.

Then take the speak to a scorchling outside the city quest, that's another. They're ramping up now!

Then 10 Blossoms for the twilight cult questline.

If you do the initial Athune quest (only once ever per character) that's 20 blossoms.

Then do your dailies every day:
10 for striking back
12ish Frost Lord Athune
5 For Tossing
5 For Catching

That's at least 512 blossoms over the course of the holiday

Then there is the running all over the place honouring and desecrating fires:

Capital Cities 100
Kalimdor 225
Eastern Kingdoms 235
Cataclysm Zones(outside the above) 30!
Outland (via portal in Stormwind) 105
Northrend 120
Pandaria 105
Draenor 75
Broken Isles 75

That's a whopping 1,582 blossom - enough for 2 pieces of level 110 heirloom upgrades per character!!!