From recent Q&A on admissions blog...
Question: Can recommenders submit recommendations after the deadline?
Answer: Yes; however, you still need to get your application and application fee paid before the deadline to be considered. We just won’t read your application until all recommendations have been received, so make sure you get your recommendation in as soon as you can. If time comes for decisions to be released and we still have not received your recommendation, we will move your application to the next round.