If you’ve ever worn a Hawaiian print shirt, it’s likely that a hibiscus blossom was part of the design. Native to the islands, the yellow hibiscus (Hibiscus brackenridgei) is Hawaii’s state flower and is an instantly recognized symbol of all things tropical.
You don’t have to live in the tropics to grow these spectacular blooms. Two hardy hibiscus varieties can overwinter in temperatures as cold as 20 degrees below zero. The main difference is the size of the plant and the size of the flowers.
One of the types is Hibiscus moscheutos, and I’ve written about them before. These small shrubs die to the ground after frost, but not before they produce weeks of flowers big as dinner plates in an ever-growing array of gorgeous colors. My plants are loaded with buds that are just beginning to open. With flowers so outrageous in size and color, they look like something straight out of a Walt Disney movie.
The other hardy type you need to meet is the Rose of Sharon (Hibiscus syriacus). It’s a larger, woody shrub that produces smaller but more abundant flowers. Trumpet-shaped, five-petal blooms in a range of colors including blue, pink, red, lavender, purple and white are centered with prominent yellow-tipped stamens. Most varieties can grow 8 to 12 feet tall and 6 to 10 feet wide, but they can be pruned to be smaller. There are pillar-types that can grow 10-16 feet in height, but won’t get wider than 3 feet.
Both of these beauties are blooming in gardens all over Yakima right now, and in some unexpected places. If you’ve driven down South 16th Avenue recently, I hope you didn’t miss the Roses of Sharon planted at Yakima Valley College. Blooming their heads off, they’re the current stars of an attractive, low-maintenance border of shrubs and ornamental grasses that thousands of passersby can enjoy for weeks. Don’t miss the deep red moscheutos-type blooming in front of the Yakima Valley College sign at the intersection of South 16th Avenue and Nob Hill Boulevard. There’s only one, but it’s more than enough to stop traffic.
That’s because regardless of the type, when it comes to flowers, hibiscus is no shrinking violet. Male and female flower parts are held high and conspicuously in the center of each bloom. And if that wasn’t enough, deep in the throat of every blossom is a darker circle, a botanical “X marks the spot,” that’s designed to entice potential pollinators. Bees, butterflies and hummingbirds love hibiscus, and it’s not uncommon to find a fat bumblebee nestled inside a blossom if you take the time to peek.
Single hibiscus blooms share the daylily’s destiny to open for just a day, but because plants are budded so lavishly, it takes weeks for all of them to open. Bloom time comes in late summer, when most other perennial flowers are exhausted, adding color to a garden when it’s needed most.
Full sun and regular watering until they become established is all a Rose of Sharon needs. Little actual pruning is necessary, and then, only if you must. They can look stiff if topped or otherwise badly pruned. Consider cutting the whole plant back to 4-6 inches from the ground, in spring before the new growth emerges. I suspect that this is how the plants at the college are managed to keep them a compact and bushy 4 feet by 4 feet. (I give my moscheutos-types the Chelsea Chop in late-June). Stems on mature plants can be quite woody, so be prepared to use heavy loppers or possibly a saw.
These Rose of Sharon cultivars gained Britain’s Royal Horticultural Society’s Award of Garden Merit. When I visited the RHS gardens at Wisley, guests were invited to tour the expansive trial gardens. Multiple varieties of the same plant are grown together, side-by-side, and rigorously compared and assessed by an expert panel. Though based on growing conditions in Britain, their recommendations should hold for Yakima gardens.
• Blue Chiffon (blue, semi-double)
• Diana (single, white)
• Hamabo (pale pink, red center)
• Lavender Chiffon (pale lilac)
• Meehanii (pink, variegated leaves)
• Blue Bird (blue-violet, maroon center)
• Red Heart (white, red center)
• White Chiffon (white, double)
• William R. Smith (white, single)
• Woodbridge (deep pink)