Question
what time of the year do you plant day lillies and when is their growing season.

Answer
Hi Carol,
Thanx for your question.  Plant your daylilies in the spring after the last frost or in the fall at least 30 days before the first frost.  Daylilies planted this year, may not bloom.  Fall planted daylilies almost always bloom the following spring.  Growing season is from mid-Spring to first frost.  They bloom in the summer usually from June to July but some rebloom like Stella D'Oro which will bloom somewhat continuously into the early fall.  I hope this helps.
Tom