Do you say "Dah-lia" or "Day-lia"?

For me,  it’s Dah-lia.  Why?  Dahlias hail from Central America, namely Mexico.  If we honor the Spanish in the region, and recall the helpful Spanish 101 rhyme “A E I O U, el burro sabe mas que tu” (ah, ay, ee, oh, oooh…), we would certainly say Dah-lia.  “Day-lia” would need to be spelled Delia. 

But that’s just me.  How do you pronounce it and why?