The Homeowners Column

The Homeowners Column

Handsome Hibiscus for House and Gardenscapes

Photo of Sandra Mason

Sandra Mason
State Master Gardener Coordinator
slmason@illinois.edu

Expectations. We all have them. But our expectations don't always convert into reality. Imagine the tuxedoed man waiting for the arrival of his escort service date to the opera but a hairy armed guy driving a truck topped with a flashing yellow light shows up.

Hibiscus are popular garden flowers, but many species exist. Will they survive outside during winter? Will they live in a container in the house? It all depends. Most of the over 200 different species of herbaceous and woody hibiscus are tropical or subtropical. Many hibiscus are not winter hardy; however, some are native to Illinois so our winters come naturally.

Generally hibiscus are known for their large, brightly colored flowers. The male and female flower parts are held as a dominant column in the center of the funnel-shaped flower. For the most part hibiscus are all sun and moisture lovers. Beyond that, it's hard to know what to expect from hibiscus.

Shrub hibiscus also known as Rose-of-Sharon, Hibiscus syriacus is blooming right now in many landscapes. Winter hardy to zone 5 it can, however, experience stem dieback after a rollercoaster winter. The 3-4 inch flowers of white, red or purple, usually with dark "eyes", are borne abundantly along stems for several weeks in summer. Leaves are three-lobed and dull in contrast to the glossy leaves of tropical hibiscus. Hibiscus shrubs can reach twelve feet tall, but a good prune in spring can keep them smaller. A 30-mph identification feature is their extreme vase shape and their multitude of summer flowers. Shrub hibiscus looks best in the back of a flower border with an apron of perennial flowers. Beauty or not watch out, these shrubs can reseed.

Another summer beauty is Hardy Hibiscus, Hibiscus moscheutos, native to Illinois and most of eastern U.S. Rotund and robust, hardy hibiscus is known for its large leaves and bodaciously big flowers. Plants are generally 2-3 feet tall but can reach 6 feet tall and do not form woody stems. Leaves can be 4-10 inches long and flowers can be dinner plate size at 10 inches wide in some hybrids. Flowers may be white, pink, and shades of red, often with darker center "eye". Unfortunately Japanese beetles also love the flowers.

As with other herbaceous perennial plants the stems die to the ground each year. Hardy hibiscus is late to emerge in spring so don't give up too soon. Many hybrids exist. Some good performers include 'Candy Stick', 'Clown', 'Pink Giant', and 'Sleeping Beauty'. For an excellent discussion of hibiscus cultivars check out Chicago Botanic Garden Plant Evaluation Notes on Hibiscus https://www.chicagobotanic.org/downloads/planteval_notes/no4_hibiscus.pdf

The glossy lobed leaves and brightly colored flowers of tropical hibiscus, Hibiscus rosa-sinensis, make these popular plants in southern landscapes and northern housescapes. The plant can live through cool but not cold temperatures; however, it needs heat to flower. If temperatures drop below 60 degrees, flowers are no longer produced until heat returns. Even cool nights will lessen flower production. Tropical hibiscus live happily indoors in a sunny warm spot.

Another hibiscus found in garden centers has show-stopping red leaves, but seldom flowers in Illinois. The glossy red leaves of 'Red Shield', Hibiscus acetosella, are lobed to resemble a red-leafed silver maple. This is no shrinking violet since it can reach 8 feet tall. But if you want 'Red Shield' to come back next year, it will need rescue from winter's cold. Dig it before frost, trim back if needed, plant in good potting soil, and grow it indoors in a sunny place.

Remember the gardener's mantra - save the plant label. It will help shape your expectations.

Visit the Master Gardener Idea Garden on south Lincoln (just south of the corner of Florida and Lincoln Avenues) in Urbana to enjoy the beauty of handsome hibiscus.

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