Purchases don't include ash - a tree popular at Christmas? (6)

I believe the answer is:

spruce

I'm a little stuck... Click here to teach me more about this clue!

'tree popular at christmas?' is the definition.
'spruce' can be an answer for 'tree' (I've seen this before). I am unsure of the 'popular at christmas?' bit.

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for spruce that I've seen before include "Smart and tidy - tree" , "Well-groomed - tree" , "Neat and tidy like tree" , "perfect condition" , "Evergreen pyramid-shaped trees" .)

I've seen this clue in The Irish Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.