Two Outstanding National Arboretum Introductions
Three different plants are commonly called Hibiscus - the tropical houseplant, the perennial rose mallow with dinner plate-sized flowers that dies to the ground each fall and the Rose-of-Sharon or shrub Althea. Rose-of-Sharons are easy-to-grow, tall flowering shrubs that will bring amazing color to your garden throughout the summer. Native to much of Asia, they thrive in the heat of summer. The USDA has introduced four cultivars of Rose-of-Sharon over the years. Two are unimpressive; two are outstanding - in our opinion the two best Rose-of-Sharon in existence: Hibiscus syriacus ‘Helene’ and Hibiscus syriacus ‘Diana. '
'Helene’ produces gorgeous, pure white flowers with prominent ruby red throats. ‘Diana’ produces waxy, pure white flowers.
Both are a vase shaped, multi-stemmed deciduous shrubs with a vigorous upright growth habit. They mature to a height of 8-12 feet by 6 feet wide and can be trained as a large shrub or a small tree. Both varieties produce flowers with broad overlapping petals of an unusually heavy waxy substance. Both are also virtually sterile so they produce no unwanted seedlings, which are the bane of the common Rose-of-Sharon. Sterility also causes these varieties to be unusually long blooming as they produce more flowers in a futile attempt to set seeds. The beautiful flowers are enhanced by the deep green glossy foliage - deeper green than I have seen on any other Rose-of-Sharon.
Either variety can be trained as a small tree or planted in masses as a screen. ‘Diana’ and ‘Helene’ are particularly attractive planted around a deck, patio or swimming pool - either in the ground or in pots.
Planting and Care
Alan Summers, president of Carroll Gardens, Inc. , has over 30 years experience in gardening and landscape design. He has made Carroll Gardens one of America’s preeminent nurseries, having introduced more than 20 new perennials and woody shrubs over the years and reintroduced numerous “lost” cultivars back to American gardeners.
Carroll Gardens publishes a weekly online newsletter written by Alan. It contains valuable gardening advice and tips and answers to customer questions. Click here to sign up for the Carroll Gardens weekly enewsletter.
Every Saturday, Alan hosts a call-in gardening forum on WCBM radio - 680 AM. For those outside of the WCBM listening area, they can listen to radio show via the internet.
Visit CarrollGardens.com to learn more.