Let’s face it, there aren’t a whole lot of shrubs that bloom in August. Rhododendrons dominate spring and hydrangeas take front stage in early summer, but when it comes to late summer, the pickings are slim. Of the few players that actually come into bloom this time of year, hibiscus are on the top of my list. Also known as Rose of Sharon or Althea, these extremely hardy shrubs/small trees will brighten up any garden in the waning days of summer.
Rose of Sharon (sometimes we refer to it as a hardy hibiscus) is in the Malva family, which includes many familiar plants that we grow in our gardens, such as Hollyhocks and Lavatera. As a whole, they are all sun and heat lovers that perform best when situated in the hottest parts of our yards. In the case of Rose of Sharon, I have seen it growing in shadier areas but it blooms much later in the season. Other than sun, they are not fussy and I have rarely seen any pest issues to be concerned about other than an occasional aphid infestation.
Traditionally, Rose of Sharon is a single flower (the classic hibiscus form like we think of from Hawaii, only smaller) and in colors of white, pink, purple, and even blue. Over the years, breeders have developed double-bloom forms that look more like carnations and bi-color bloom forms that often have deep purple throats. As a whole, I think they all have a rather tropical look about them, which as many of you might know, I tend to be drawn to.
As for pruning, you can either grow them into small trees 10’ to 12’ tall (you can also buy them already trained into standards, if you prefer a more formal look in your garden) or keep them in shrub form and cut them back hard every spring, much like a rose where they will top out around 4’ to 5’ tall. They bloom on new wood, just like a rose, so you will always get flowers, no matter how much you abuse them with the shears.
In addition to new color combinations and more compact growth habits, breeders have also managed to increase the size of the flowers. Proven Winners brand has come out with their ‘Chiffon’ series with 3” to 4” blossoms on plants that will grow up to 10’ to 12’ tall. Bailey Nurseries has introduced, in their First Editions line of shrubs, several flavors with tropical names like ‘Tahiti’, ‘Fiji’, ‘Bali’, and ‘Hawaii’ that sport large flowers (some of which are double or semi-double blooms) and a much more compact habits that only grow 3’ to 4’ tall, making them good candidates for container plantings. You can’t go wrong with any of these new introductions.
In addition to Rose of Sharon, there is a perennial hibiscus (which is actually native to our east coast) that dies back to the ground every winter, emerges late in the spring, and grows 5’ to 6’ tall by the end of summer with ginormous flowers that can reach almost a foot across. The native species is a bit underwhelming for us sophisticated gardeners, but the new hybrids are absolutely to die for. If you are an older gardener you might remember names like ‘Lord or Lady Baltimore’ as the only choices. They were very tall and lanky growers that invariably set blooms so late in the season that most of the flowers would abort once we had a few cool nights in the 50’s and 60’s. I know I tried a couple, but I eventually ripped them out and threw them on the compost pile - it was always disappointing.
Well, times have changed! Proven Winners has introduced an exciting new series called ‘Summerific’ (or commonly called Rose Mallows). There are around 10 different colors to choose from and most of the plants have dark burgundy foliage that adds to the drama. The plants stay compact at 3’ to 4’ tall, unlike ‘Lord Baltimore’, and are multi-branched giving them more of a shrub-like appearance. With climate change staring us in the face, being able to grow these incredible perennials on the west side has got to be a silver lining. Look for names like 'Holy Grail’, ‘Berry Awesome’, and ‘Candy Crush’. They start arriving in the garden center this time of year.
Finally, if you long for the tropical hibiscus like they have in Hawaii, remember that you can indeed grow them here and they will bloom all summer long. Either move them in as a house plant for the winter or toss them out along with the marigolds and petunias and buy some new ones next spring. I do this all the time without one single bit of remorse. And remember, don’t ever feel guilty about tossing out a plant. In Nature, everything gets recycled.
