Forsythias or PJM Rhododendron and azaleas would all be great choices that flower around now and this is the best time to plant them. There is also a native Amelanchier aka Shadblow or Serviceberry that is flowering now with white flowers that would be a good choice for planting now. More on that HERE
https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=j290