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Herbaceous Perennial Hibiscus

hibiscus collage

There are lots of different hibiscus out there.  Tropical Hibiscus are used as landscape plants in Hawaii, Florida and other climes that are usually warm—or even tropical—year round.  Here we use them as patio plants in the summer, and houseplants in the winter.

The shrub, Rose of Sharon, is a Woody Hibiscus.  Officially Hibiscus syriacus, it is the National Plant of South Korea.  Rose of Sharon does well here but has a reputation for weediness, although some of the newer forms don’t seed out into the garden like the older ones did.

What I am writing about is a third type of Hibiscus, the Herbaceous Perennial Hibiscus that die to the ground each winter, overwinter as a crown, and resprout in late spring to flower in summer.  Most of the perennial hibiscus that we sell are hybrids between several species, many of which are native to Maryland.  You should be able to see them in bloom in summer in marshy areas (for example, where the Patuxent River crosses Highway 4 east of DC; big white flowers).

Behnke Nurseries has sold perennial, or hardy, hibiscus for many years.  Through a relationship with the breeder, Robert Darby, we were the first to sell Hibiscus ‘Lord Baltimore,’ the classic red.  This was back in the 1950’s, when Mr. Darby was working part time at Behnke’s, in addition to his “real” job at USDA.  Mr. Darby also released the popular pink hybrids ‘Lady Baltimore and ‘Anne Arundel,’ and ‘Turn of the Century,’ which looks like a pink and red pinwheel.

Behnke’s also released Dr. Harold Winter’s ‘Blue River II,’ which is the classic white hibiscus.  (Rumor is we may have done this a little sooner than he would have liked.  One of those situations when a sharp propagator’s knife sometimes has a mind of its own.)

As with many other perennials, there has been an explosion of releases of hibiscus cultivars in the last fifteen years or so.  Breeders have focused on: flower size (bigger); flower shape (petals that overlap to give a fuller appearance); flower color; and plant height (some shorter cultivars that are great for containers).

Our best selection is in mid-summer when they are blooming.  They also are a bit difficult to overwinter in pots, so the cuttings are usually potted in late spring.  As a result,  we seldom have many before late June.

Depending on the cultivar, mature hibiscus range from a couple of feet to over 6 feet in height.  They are late to emerge from the ground in spring, usually you don’t see new growth until around May 1.  They then grow rapidly and begin to bloom around the 4th of July.  Each flower lasts but one day but they bloom pretty much continually into September.

Flowers are big, bold and tropical-looking, and come in white, pink, plum, red and bicolors.  Foliage may be green or red depending on the cultivar.  They do best in full sun (six hours or more of direct sun) and being swamp plants, they prefer moist soil.

They have some issues with insects, but hibiscus are so vigorous that they generally outgrow them.  Japanese beetles are the worst (several weeks, mid-summer) and can shred the foliage.  Because of this, hibiscus are a better background plant than something to plant on either side of the front door.

So if you are looking for a red perennial (and there aren’t many)—try a hardy hibiscus.  And the pink, white, plum and other cultivars are spectacular as well!

By Larry Hurley – Behnkes Perennial Plant Specialist

Larry Hurley, perennials specialist for Behnke Nurseries (now retired), started with Behnke’s in1984. Larry enjoys travel, food and photography. He and his wife Carolyn have visited Australia, New Zealand, Thailand, Brazil, South Korea and much of Europe. Their home is on a shady lot where a lot of perennials have met their Maker over the years.

This Post Has 2 Comments

  1. I’m looking for information about propagating hardy, herbaceous hibiscus from seeds from my existing plants, in Dayton, Ohio, zone 5 or 6A.
    – If I simply plant some of the seeds this Fall in our community garden, can I expect them to germinate reliably in Spring? I have a set of 4 different varieties and I’m unable to find info only about growing my herbaceous hibiscus from seeds.
    – Your advice will be appreciated.

    1. Here is a link to a detailed guide to propagating hardy hibiscus. https://gcrl.usm.edu/cpr/docs/planting.guides/CPR.Hibiscus.moscheutos.pdf In our rain garden, where we left seed in place to fall at will, I found that they would pop up randomly here and there the next summer, at a low percentage rate.

      When we propagated them, we were doing it from cuttings, except for a small breeding program that one of the staff was conducting on his own for a couple of years. For that, he was germinating the seed in the greenhouse, but I no longer remember much about it. It was almost 30 years ago.

      Larry Hurley

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