About the Rose of Sharon - Ardens :
The Ardens Rose of Sharon, Hibiscus syriacus Ardens, is an upright, deciduous shrub is that is vigorous, erect, multi-stemmed shrub that typically grows 8-12' tall. This shrub may also be trained as a single trunk tree or espalier. Leaves are diamond-shaped, dark green, slightly palmate and toothed. 'Ardens' bears blue flowers from late summer until mid-fall. This plant really requires no pruning, unless you need to remove a dead or damaged branch.
It has a long, early summer to fall bloom period. This cultivar is a sterile triploid that produces very few if any seed pods. It is an excellent flowering shrub that may be massed, planted in groups, or used as a specimen. The plant is very tolerant of summer heat and humidity. Larger flowers may be obtained by pruning back hard to 2-3 buds in early spring. Otherwise, prune to shape.