@Becky
In most plant species the size of the plant determines the probability that the plant will flower. In daylilies that size is related to the size of the fan rather than the clump.
The easiest way to measure the size of a fan would be to count the number of leaves. That is an approximation and a fan with a narrow crown might have many small leaves. Perhaps a more accurate measure of a fan's probability of flowering is its width (along its widest dimension) at the soil surface. The larger the width the more likely the fan will flower and vice versa. However the probability that a cultivar will flower at particular sizes is determined for each cultivar by the cultivar's genetics.
I will measure the fans in a clump tomorrow and check whether each fan is flowering and how many buds it has and then post the results here (as long as the rain stops for long enough during the day). I have done this in the past and I may be able to find those results as well..
