Every now and then, after years of considering a plant on its periphery, my lack of knowledge reaches critical mass, and I have to finally dive into its depths.
Such is the case this summer with hibiscus (tropical and hardy) and rose of Sharon, which also is a type of hibiscus. The flowers on these relatives are similar, and they can be confused with one another.
I’ve grown tropical hibiscus, which is an annual here. Its tropical colors and names such as Baja Breeze carry me away from land-locked Wichita.
I’ve also grown rose of Sharon, which is a hardy flowering shrub. It’s not my favorite, but where would we be without its tissue-paper summer flowers? Definitely even farther away from Baja.
I have not grown hardy hibiscus. It survives our winters, and its flowers can reach dinner-plate-size. I find that kind of weird on a relatively small plant, but I bet I’d be thrilled if I was the one growing it.
This week, master gardener Lisa Folds told me about an unusual and beautiful hibiscus she bought at Lowe’s. It has leaves of three, like poison ivy, except these leaves are purple-black. And it has red flowers. The tag with the plant said its name was Red Luna hardy hibiscus, but the plant on the tag bears no resemblance to the plant Lisa brought home. An online search confirms that the leaves on the Red Luna (aka Balhibred) are green, not purple-black. So what is Lisa’s plant? And is it hardy or tropical? She needs to know if she can leave it outside for the winter or will have to bring it indoors to keep it alive.
A story from the Fort Worth Star-Telegram that I’d squirreled away gave a clue to the Mystery of the Black Hibiscus. (I recently reread a childhood Nancy Drew mystery — “The Secret of the Golden Pavilion” — that took place in Hawaii. And it turns out the yellow hibiscus is the state flower of Hawaii.) The Star-Telegram says that hardy hibiscus plants establish as clumps of many stalks, while tropical hibiscus produce branches. Flowers are borne for several months at the tips of the stalks of tropical hibiscus, the story says.
Lisa looked at her plant and determined that the stems of her hibiscus do not produce branches but simply shoot up straight from the ground. She figures it must be hardy — a good thing since she has it planted in the ground — but she’d still like to know its name. If any of you are Nancy Drew-like sleuthers, take a look at the photo on this page and see what you can come up with.
I found that other plants are related to hibiscus as well, including okra, cotton and hollyhocks. They’re all in the malvaceae or mallow family.
Botanica grows both kinds of hibiscus, as well as rose of Sharons (or is it roses of Sharon?).
“The tropicals tend to have a darker, shinier foliage,” landscape supervisor Pat McKernan says. “They have the longest bloom season of all of them.
“The hardy hibiscus put on a great show while they’re blooming. You don’t have to replace them every year. They’ve done really well for us. I think we have 23 varieties.” Pat says that Botanica gardeners cut the hardies down to 2 to 6 inches high each spring, and daffodils flowering among them help hide their short stems. (The hibiscus can be cut all the way to the ground because they come up from the roots, but Botanica likes to keep track of where they are.) Hardy hibiscus usually grow 3 to 5 feet high.
Rose of Sharon get 8 to 12 feet high and make a nice screen, Pat says, filling the void in flowering shrubs in the late summer.
“We’ve been bringing in some of the newer ones,” he says, including the more-petite Blue Satin and Lavender Chiffon in the Downing Children’s Garden. There’s also a dwarf variety now, Miss Kim, which gets only 3 to 4 feet tall. I once saw a yard that had alternating colors of rose of Sharon edging the lawn, and it was highly peppy.
All of these plants like their water in order to flower well.
“Their new buds will continue to develop as long as you keep the plants consistently moist and well nourished with a water-soluble, high-nitrogen fertilizer,” Neil Sperry writes of tropical hibiscus in the Star-Telegram. “They require almost full sunlight, although a little protection from the mid-afternoon sun in midsummer may slow down their likelihood of wilting. Hibiscus plants of all types abort unopened flower buds when they are allowed to get even modestly too dry.”
It dawns on me that I don’t have any hibiscus this year. I vaguely remember trying to decide among some colors and deciding that I was a yellow person when it comes to the tropicals. My next thought is: Are these plants good for wildlife?
Apparently, hibiscus and rose of Sharon attract hummingbirds, but I’ve also read that the nectar of these plants is not the most desirable. So I’m thinking, for those of you who have these plants, if you put a few hummingbird feeders close by them — and you want to do that starting at the end of this month when hummingbirds are starting to bulk up — that would probably be a great partnership.