by Anne K Moore for GardenSMART / Photo by Anne K Moore
If you haven’t looked at the newer altheas (Hibiscus syriacus), also known by various common names of rose-of-Sharon, hibiscus, and mallow, your garden is missing a tough little woody plant. It adapts to USDA Zones 5-9, and does well in clay or sand as long as there is plenty of compost worked into the soil to keep it well drained and moisture retentive. Altheas are full sun lovers in the North. They do appreciate some noontime and early afternoon shade in the searing sun areas of the country. They are not too fussy about water, either. Just give them a drink if the summer rains don’t come along.
In the summer, at a time when there isn’t much going on in the shrub border, you can expect altheas/hibiscus to put on a show. They are precocious bloomers, blossoming as very young shrubs. I was sent three altheas from Proven Winners for trial in past years and I love them all. I believe all three I trialed bloomed their first year at only a non-statuesque foot to foot-and-a-half tall.
Blue Chiffon™ is that medium blue, almost-but-not-quite purple. He puts on flowers with a large outer ring of petals and a lacy center with red peaking out of the center circle. I find him very handsome.
Lil’ Kim™ is a single white with a large maroon red center. At three to five feet tall, she is said to be good for a pot, but she shot up so I planted her in the ground. She is about eight feet tall now in my garden. She also does not set seed, so there are no messy seedlings to get rid of. Lil’ Kim is a prolific bloomer, even in part shade.
Perhaps my favorite is Sugar Tip® with its double pink flowers floating atop variegated foliage of creamy white and bluish green. It is a very girly-girl pastel plant.
There are so many althea flower forms to choose from, from single petal style with flat or ruffled edges to flowers fully gathered and ruffled into scrunchy puffs. Many have a light petal with a dark eye. A couple of my old favorites are ‘Bluebird,’ which has been improved to Blue Satin® and the most elegant of them all is the old favorite, large-flowered white, ‘Diana.’
One of the advantages in using althea/hibiscus in the garden is its fast growth and eagerness to bloom. Usually they are a tall shrub, five to eight feet. The natural form, branching in the shape of a triangle standing on its point, fits well into a small space. They look super with one or multiple trunks limbed up and trained into a tree form.
These shrubs blossom on new wood, so trimming back in late winter will bring more branching and more flowers. Cut the branches flush back to a juncture. Remember, any cut will force growth at that point. Tip pruning is not advisable. It makes for weak arms that will not support the load of flowers on the ends.
Altheas break dormancy late and go dormant early. If you use any as a pot plant, fill in underneath with spring bulbs for early color. In fall, add some pansies under the limbs and some ivy or other billower to trail over the side.
Next spring, when the pansies and bulbs are going by, your althea/hibiscus will be waking up. Then you can pull out the skirt of pansies and add your summer annuals. I’m fond of using ornamental sweet potato vines. ‘Blackie’ looks great under Lil’ Kim, but needs trimming or he will spill out and take over your nearby garden world.
Welcome althea/hibiscus/rose of Sharon/mallow (Hibiscus syriacus) into your garden. They are most welcome in mine.