Blossom v Flowers

Colour again after two monos, phew... ornamental cherry flowers blown under my camellia, with some weed flowers I put there for contrast.

We have a Sri Lankan family in our group, and they started us thinking, exclaiming over the flowers on our apple trees. I said that we call it blossom, so then we tried to define when it's blossom and when it's flowers. Harder than you think.

Internet said it was fruit trees - but what about ornamental blossom, or blackthorn? It said it was in the Spring, but what about orange blossom? It said it fell in heaps on the ground - but forsythia does that, doesn't it?

Intriguing how one knows something in one's own language, but without knowing why... Like, when do you get up from the table, and when do you get down??