The Rose of Sharon (Hibiscus syriacus) is a deciduous shrub that provides color during the late summer and early fall. This hardy hibiscus is a member of the mallow family, known for its upright, vase-shaped growth habit. It thrives across a wide range of climates, tolerating heat, drought, and various soil conditions. It is reliably hardy in USDA Zones 5 through 9.
The Core Color Spectrum
The range of colors available in Rose of Sharon cultivars is broad, encompassing nearly every cool-toned shade but excluding true red or yellow. White varieties provide a luminous contrast against the dark green foliage. Cultivars like ‘Diana’ produce large, pure white petals that can brighten a shady garden spot.
The pink and rose category is the most common and diverse, featuring soft, pastel blush tones to deep, vibrant magenta hues. Cultivars such as ‘Aphrodite’ showcase a rich pink color. This group provides a wide palette of shades that reliably produce color throughout the summer.
Lavender and purple flowers offer a sophisticated tone, ranging from pale mauve to intense violet. Varieties like ‘Purple Pillar’ feature deep pigmentation that makes them stand out in the late season garden. These colors are often confused with the specialized blue varieties.
While many cultivars are marketed as “blue,” the color is technically a strong lavender or violet-blue due to the plant’s natural pigments. True blue is genetically difficult to achieve in this genus. Cultivars like ‘Azurri Blue Satin’ and ‘Blue Chiffon’ produce the closest approximation, presenting a striking, cool-toned flower.
Understanding Flower Variations and Markings
The Rose of Sharon flower is characterized by a distinct central marking known as the “eye” or throat. This feature is typically a deep, saturated color, most often maroon or dark crimson. The contrast between the main petal color and this central spot creates a powerful focal point.
In many varieties, especially those with white or light-pink petals, the dark eye is sharply defined, as seen in the cultivar ‘Red Heart.’ This pattern gives rise to bi-colored flowers, where the outer petals have one hue and the center features the dark marking. The pigment concentration in the throat draws attention to the prominent central reproductive structures.
In some newer cultivars, the contrast may be subtler, with the darker pigment radiating outward in veins that fade into the petal color. This deeper coloring adds depth and complexity to the overall flower, preventing solid colors from appearing flat. The central marking is present regardless of whether the bloom structure is single or double.
Single Versus Double Bloom Structure
Rose of Sharon flowers exhibit two main structural forms that affect the visual weight and color presentation of the blooms. The classic “single bloom” is the most common, featuring five distinct, widely spaced petals that open flat, creating a clean, trumpet-like shape. This structure offers an unobstructed view of the central eye and the prominent stamen column.
In contrast, “double blooms” contain multiple layers of petals, which can vary from a semi-double form with a few extra ruffles to a fully double, pom-pom-like appearance. Cultivars in the ‘Chiffon’ series often feature this fuller, more ruffled structure. These multi-layered flowers appear significantly denser and more saturated in color because of the overlapping petals.
The double structure can sometimes partially obscure the characteristic central eye, giving the flower a more uniform appearance. While single blooms are lighter and more delicate, the full, robust nature of double blooms provides a heavier texture and a greater visual impact. Both forms maintain the same core color palette, but the density of the petals alters the final perception of that color.