My goodness msmorningsong, you do not exactly have an avalanche of comments here :-D. I am not familiar with Scabiosa and have not grown it, but they do appear to be nectar rich for pollinators. I have some tips though. In general pollinators will appreciate a single or double layer of petals which offer easy access to the nectar (i.e. avoid the pom poms). I would choose singles if i were buying them for my butterfly garden and i would buy a variety that is the least modified by humans (not overly bred; closest to the original wildflower). In my experience, the wildflowers are the most popular go-to flowers in my garden for the nectar lovers. I hope this helps a little bit.

From what I have read here over the years, it appears that different plants are attractive to different butterflies at different times. I'm hypothesizing that the amount of nectar produced by a particular plant varies according to certain variables,,such as temperature, sunshine and amount of rain. Your best bet is to have the widest diversity of flower, so you'll always have something attractive to them. That will guarantee you have as many butterflies as possible. It also helps to plant them in solid drifts of one type or another, so they are more easily noticed.

So fun to read about all you are doing to bring these beauties into your yard.

Martha