There are several possibilities for this.

1. Are these new daylilies? New daylilies often do not reach the registered scape height for three years.

2. For me, a lack of rain in May caused some scapes to be short.

3. Southern evergreens are often not as tall as registered when grown north of where they are bred.

Debra

Also, check to see where the scape is coming from. If it is coming from the outside of the fan, it's a scape that began to form last season, but didn't get the chance to grow until now. Those scapes (we call them cheater scapes, some call them prebloom scapes) are usually shorter with fewer buds and are seen abnormally early. If that is what they are, the plant should then bloom on its regular schedule with its regular height.

Nancy