Flowering shrubs are important structural elements in gardens and provide reliable blooms at various times of the growing season. In the fall, as our annual plants grow tired, it is helpful to have shrubs with blooms that freshen the landscape. The Rose of Sharon "Hibiscus syriacus" belongs to the genus "Althaea": the genus to which hollyhocks belong.
The Rose of Sharon flower is indeed, very similar to a single hollyhock. However, the Rose of Sharon is a shrub that can grow up to 12 feet tall. It is a native to China and Northern India, but has flourished in this country since the 18th century.
It will grow in both sun and light shade and is hardy to zone 5. The old fashioned purple varieties have been used extensively for hedges and some self-seed aggressively.
However 'Diana' is a cultivar developed by the National Arboretum in 1963 and it has pristine white flowers and is well behaved as a specimen even in a small garden, as is 'Blue Bird' which is an azure shade.
They bloom until frost and can be placed where height is needed in the garden. These easy care shrubs were staples in our grandparent's gardens and are useful too, for us. They give lush green growth and fresh cool looking flowers as summer wanes.