What are those big, bold, bodacious blooms you see in gardens at the end of summer, when most perennials have come and gone? There is a perennial version of the tropical hibiscus that is hearty even through our New Hampshire winters, returning late spring, slowly growing and greening until it blossoms in late summer and into early fall. It is ideal for continuing color in your garden when other perennial favorites have peaked and been reduced to providing greenery alone.
Otherwise known as Rose Mallow, the perennial hibiscus begins to show itself later than most perennials. But don’t be fooled! Its new growth comes from below ground, not on dead wood. If you’ve planted a perennial hibiscus this year, next spring all you will see is some dead, brown woody stems. You can cut them down to just above ground level, but do not pull them out. Perennial hibiscus love full sun but will tolerate light shade. And they like to be watered regularly, preferring to avoid dry soil. Try and aim for the soil when watering, avoid saturating the leaves and make sure there is enough room between plants to allow for air to circulate.
The hardy variety of hibiscus will produce many huge blooms (up to 10” across, or “dinner plate” size), depending on how well the plant is situated for sunshine and how often it is watered and fertilized. It can grow from 3 to 6 feet tall. Blooms come in a variety of pink, red, burgundy and white, often with a different color in the center of the flower. Multiple buds form on each stem and, while each flower only lasts a few days, when it dies and falls to the ground, another bud opens to reveal an equally amazing bloom. The large stamen in the center of each flower attracts native pollinators.
Where you choose to plant a perennial hibiscus will greatly affect its shape. Try to locate the hibiscus in a garden where it will receive full sun. This should result in a plant that is bushy and rounded. If they receive less sunlight, they will tend to reach for the sun, resulting in taller plants that will likely need staking.
Should the leaves of your perennial hibiscus become “lacy” due to insect feeding, the culprits may be one of the following: Japanese beetles, sawfly larvae, spider mites, whiteflies and aphids. Japanese beetles are easily spotted and can be picked off, while an insecticide soap or horticultural oil should be sprayed on the leaves, top and bottom, to ward off the others.
When considering adding a perennial hibiscus to your garden, shop carefully and make certain you read the label on the plant. The perennial version is a hybrid of the more delicate tropical hibiscus, which is not intended to last through our winter. You can also check the leaves, which will appear thicker and shinier on the tropical variety of hibiscus. And again, patience is a virtue…the perennial hibiscus is very slow to show signs of life in the spring, but the color and longevity it brings to your garden is well worth the wait.