Invincibelle® Ruby (‘NCHA3’) Smooth Hydrangea produces ruby red to soft pink mophead flowers starting in early summer. Hydrangea arborescens Invincibelle® Ruby has strong stems supporting the flowers, and it blooms intermittently throughout the summer, especially if deadheaded. Since it flowers on new wood, you can prune it hard in the spring without compromising the flower display. Another improvement by Dr. Tom Ranney of NC State University.