Divide Iris in heat of summer when dormant - July thru Sep. Recommended to divide every 3 to 4 years whether crowded or not. Use a spading fork instead of a shovel because it is less likely to cut roots and rhizomes.
Hardy Hibiscus produces showstopping 8- to 12-inch-diameter flowers! More flowering shrubs for hedges: http://www.bhg.com/gardening/trees-shrubs-vines/shrubs/best-flowering-shrubs-for-hedges/?socsrc=bhgpin072813hardyhibiscus=15
For guaranteed impact in sunny garden borders these hardy, summer flowering shrubs are unbeatable! Versatile and undemanding, this collection of deciduous shrubs provides continuous colour from March to September. Lonicera (Shrubby Honeysuckle) -Clusters of pink flowers; Buddleja (Butterfly Bush) -Purple flowers; Forsythia -Yellow star shaped flowers; Ribes (Flowering Currant) -Deep pink red flowers; Philadelphus (Mock Orange) -Fragrant double white flowers. Plant in sun or semi shade.
Bell-shaped Beautybush blooms in the late spring and early summer. More spring-flowering shrubs: http://www.bhg.com/gardening/trees-shrubs-vines/shrubs/beautiful-spring-flowering-shrubs/?socsrc=bhgpin040113beautfybush=18