From your description, it sounds like two may be a different variety. Not uncommon for a mix-up somewhere in the production/retail process.

As for the one that keeps dying, I am assuming it is always in the same spot. If so, I would investigate the spot and see if there is something different about it.

Higher?Lower? Sloped? Downspout? Significantly more sun? etc.

I think you may be correct about the labeling I could just re position those two and hopefully get two correctly identified ones.

The six plants are all in similar soil sun light The planting depth could be an issue i can check that

I had wondered if in fact this year there had been two much rain but the 5 established plants seem to be doing well

I agree completely with Ginkgonut - neighbor #1 planted a, so named, 'Annabelle' that turned out to be 'White Dome' but beautiful bush with very lovely powderpuff domes ... neighbor #2 planted hers in a shaded E facing (gets some AM sun) didn't grow as tall as mine but heftier & loaded!!! Mine a (2nd season) in a slope, N facing foundation bed ... a giant & full of saucer sized pom-poms. We went through one record-breaking 'Killing-Winter' as well as a Spring & early Summer of mostly days of rain/storms, but when the sun shows up, they were unbearably hot/steamy/scorching days ... cooked many a beautiful foliage & those tender young blossoms! Â:(

I'm glad I learned in this forum, about installing a reasonable size cage on Annabelle, she would have splayed all over otherwise!

Good luck in resolving your Annabelle problems! Â;)

i am having the same problem, however, my annabelle's used to fully bloom. Now they are getting that lacey undeveloped look like you describe. I think it is due to iron deficiency from what i have read and I am trying ironite.