Hardy Hibiscus adds a splash of tropical flair to your perennial garden.

Hardy Hibiscus adds a splash of tropical flair to your perennial garden.

Fast-growing and fabulous, these plants explode with pinwheel-like flowers the size of dinner plates in late summer. Often confused with their tropical cousins, these plants are actually capable of surviving temps as low as -30° F (-34° C).

North American gardeners can feel assured knowing they are planting a native perennial. Hardy Hibiscus are hybrids that can be primarily traced back to the species Hibiscus moscheutos. This species can be found growing naturally in wetlands and along riverbanks throughout the Midwest and East Coast, extending down even into Texas and Florida.

Know Your Hibiscus

Hibiscus is both the common and botanical name for a few different popular classes of the plant. Most think of Tropical Hibiscus (Hibiscus rosa-sinensis) when they hear the word, while horticulturists may note the shrub Rose of Sharon (Hibiscus syriacus) also falls in this category. However, neither of these plants fall into what is commonly considered “Hardy Hibiscus.”

Here is a quick overview of how they differ:

• Hardy Hibiscus

  First, our subject and superstar: Hardy Hibiscus. This set of plants primarily includes the species native to North America (such as Hibiscus moscheutos and Hibiscus laevis), and hybrids of those species. These plants are true perennials, tend to have the largest flowers, and die back to the ground each year.

• Shrub Hibiscus

  Shrub Hibiscus, also called Rose of Sharon, most frequently refers to the species Hibiscus syriacus which is native to southern and central Asia. Rose of Sharon has a woody habit and bloom on the same structure each year. These tend to be the largest in size with some varieties getting 15′ tall.

• Tropical Hibiscus

  Tropical Hibiscus, or Hibiscus rosa-sinensis, are from southeast Asia and are technically a shrub-like their cousins, Hibiscus syriacus, though significantly less hardy. These varieties tend to be used in the landscape in southern parts of the US or as patio or house plants since they are not frost tolerant.

Common Hardy Hibiscus Varieties to Keep Your Eye Out For:

Hardy Hibiscus comes in shades of white, pink, red, and yellow, with different eye patterns and streaking through the petals. The leaves of the plants can also vary in color from green to bronze and near-black.

Some of the most popular series available include:

• • Summer Spice®
  • Luna
  • Head Over Heels®
  • Summerific®

Water, Wait, and Give Them Space! How To’s for Happy Hibiscus Plants

Hardy Hibiscus have a history of growing in wet areas such as along riverbanks and around inland lakes. They perform best with consistent watering, particularly if they have been recently transplanted. If your Hibiscus is losing its lowest leaves or aborting buds, you may need to up the water!

This water-tolerant characteristic makes them perfect for areas of the garden that periodically flood, or as a thriller in rain gardens.

Another characteristic of the genus is they are late to break dormancy in spring. They’re not dead! When they do wake up they’re off to the races growing more than an inch a day. Depending on the year, Hibiscus may stay dormant through the end of May.

Instead of tearing your Hibiscus out and starting over, try planting them with tulips, daffodils, or other spring-blooming bulbs who will be out of bloom when Hibiscus are ready to emerge. As an added bonus, the tired foliage of these spring-blooming bulbs will quickly be covered by the wide Hibiscus habits.

Once your Hibiscus gets going, be sure to leave them plenty of space to grow. Mature Hibiscus can get 5-6′ wide and grow quickly during the year. If you take a week’s vacation in June, you’re likely to come back to a plant twice the size you left it.

Full sun is a must. In too much shade the otherwise sturdy habits stretch and get floppy. Over shading will also lead to a decrease in bud count and diminished flowering performance. UV light (full sun) will also bring out the dark foliage colors.