Perennial Hibiscus are relatives of the tropical Hibiscus rosa-sinensis and the hardy shrub H. syriacus known as rose-of-Sharon. Perennial Hibiscus are winter hardy plants that are completely herbaceous, dying back to the ground each winter and coming back fresh in mid to late spring (they are always late to break dormancy). Amazingly, though they look so tropical, they are hardy to zone 4! For gardeners in colder climates you could grow them in containers that you protect in the winter.
The perennial Hibiscus are bred from H. moscheutos and other species native to the eastern US and Canada. The garden hybrids offer the largest flowers in the genus with diameters reaching 8-10 inches, sometimes more, and thus are sometimes called “dinner plate” Hibiscus. At Phoenix Perennials we carry many cultivars from various breeding programs but this year we are quite excited about the Summer Spice collection.
Hibiscus Summer Spice ‘Bleu Brulee’
The Summer Spice collection is bred by Dr. Dariusz Malinowski at the Texas A&M AgriLife Research and Extension Centre in Texas. He and his team are working on developing compact, free-flowering cultivars with unique flower colours and flower shapes. Their success is our gain with the first blue-flowered perennial Hibiscus. This year we will have three different blue cultivars called ‘Bleu Brulee’, ‘Brandy Bleu’, and ‘Cordon Bleu’.
The new colour breaks are not limited to the blues. ‘Amaretto’ is a unique coral pink, ‘Ambrosia’ and ‘Crepe Suzette’ have incredible glowing fluorescent pink and magenta-red flowers, respectively, ‘Grape Sorbet’ is a novel purple with a central magenta glow, and ‘Creme de la Creme’, while not offering a unique colour—it is white with a red eye—has notched petals which give a unique look.
The Summer Spice collection are currently listed as hardy to zone 5 though Canadians with zonal denial who live in zone 4 might give them a try with good winter protection since other perennial Hibiscus are hardy to zone 4. Indeed, breeders introducing new plants often suggest conservative hardiness ratings at first only to find out later that plants are hardier than first thought. If you live in a colder zone, perennial Hibiscus are easy to grow in pots and protect in the winter since they go totally dormant.
The Summer Spice cultivars will generally grow as branching plants to three feet high and wide blooming from July through to the fall with flowers about eight inches in diameter.
Here is the new Summer Spice Collection: