Knowledgebase
Shrub #871737
Asked June 05, 2024, 2:15 PM EDT
Hennepin County Minnesota
Expert Response
https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=280851
As for the center, it is common for perennials to die out in the center. It is a sign the plant needs dividing:
https://yardandgarden.extension.iastate.edu/how-to/how-divide-and-transplant-perennials
You can fix this by digging up the plant, cutting away and discarding the center, and replanting the side pieces. Of course, that is best done in early spring before the plant gets too large. The next best time would be late summer, at the end of August. If you must do this now, be sure to give it plenty of water to help it recover.