Ruby Clusters is a wonderful bloomer with showy clusters of tubular crimson red flowers. After flowering, reddish-purple berries appear adorning the arching stems with a backdrop of dark green foliage. Prune after flowering as the blooms form on the tips of the stems that grow during the summer. Sensitive to shortened day length, Ruby Clusters comes into bloom in fall and flowers for us fall, winter and spring. It puts on a sensational floral show when color is needed the most. This Cestrum doesnt mind it cool as we grow it in a greenhouse that has night temperatures in the 40s.