If you look at a lot of the websites who cater to Valentine's shoppers (flowers, sweets, jewelry) - you'll see that most make no mention on their home page about shipping deadlines.
Here are a few that are trying.
Hickory Farms is the most clear - they include the date. (An obvious and necessary fact.)
See's, Mrs. Fields, and Harry & David do mention on the home page, but are not as clear about options.
Some of the bigger retailers did a better job in December. Check out my earlier blog posts