I am in Zone 9b. Our nighttime temperatures this spring have seemed cooler than usual, and I have little experience with the effect of cool temperatures on diurnal daylilies.

The first flower of the season on Samuel Bell began opening two days ago. I noticed it about 6:00 pm when it was about half opened. It opened fully mid-morning yesterday, and it is still open this morning at 9:00 am.

Here is a picture of it this morning more than 38 hours after I saw it half-opened.

I know it is a diurnal with an extended bloom, but is this very long extended bloom unusual?

For those of us who live in cool areas, that's not all that unusual. Flowers of heavier substance can take several days to open if the temperatures are cold. Last Fall, it was taking Voila Francois four to five days to open fully and by the time it did, the earliest parts to open were already spoiling. Around here ( Boston) I usually see that effect in the Fall because Daylilies aren't ready to open until mid June by which time it's warm enough for them to open correctly. However, many of them will rebloom until frost and that's when you see the lengthy opening times.

@Zoia. Thanks for clarifying that. I suspected that the cool nights were the reason that it is open for such a long time. What a bonus!

We are headed out of town for a couple of days, so. Won't be able to see how long it lasts.

I have noticed that the buds on many different cultivars are taking a long time to open. It seems like the scapes have been at full height forever! Guess I am too impatient, but the reward might be that each bloom is pretty for a longer period of time.

Good info to know.