Hardy Hibiscus

 
Hardy hibiscus (Hibiscus moscheutos) is known to have two main characteristics, giant blooms and being a very cold tolerant perennial.  Yes, even the cold brutal winters of Michigan’s zone 4. These plants are known to produce blooms that can vary from 4” up to a giant 13” dinner plate sized diameter.  The hardy hibiscus differs from the tropical hibiscus (rosa sinensis) which is grown in warmer more tropical climates and is not likely to survive cold winters unless potted and placed indoors for the winter.  The hardy hibiscus is also known as Rose Mallow or swamp mallow and is native to North American swamps.  These perennials will tolerate temperatures in zones 4 – 10, and marginally in zone 3 with extra winter protection. Most often the blooms are pink, rose-pink, red or white with a touch of colored centers or peppermint veins.  These plants did not get much attention from hybridist until a few years ago when several noted hybridist began developing various strains.  Today there are more colors and variety to choose from.

Swamp mallow plants will come up religiously every year and with proper care bloom late in the fall till the first frost.  If seed pods are kept picked off, your plant will continue producing multiple blooms later into the much cooler fall weather till the first frost. 

There are 3 ways to begin growing the hibiscus; from seed, cuttings taken from the plant or from root stock. When planting young hibiscus perennials we prefer those grown from root stock cuttings rather than from seed because roots are more established and it will start to bloom (weather permitting) around 10 weeks after planting.  Hardy hibiscus require much less care than the tropical variety.  Once established they will grow under a variety of conditions and are friendly to most soil.  You can grow the shorter versions (3 ft.) in water up to 6” deep.  This makes them perfect for low lying areas that collect water or a water garden.  Rose mallow are not as likely to attract pests as the tropical version, and require no pruning. If you purchase 4”-6” pots at the beginning of spring, once established you will have fabulous blooms from mid summer till winter . 

Winterizing Hardy Hibiscus is simple.  Wait until the first frost and cut the base of the plant. These bloomers need a period of dormancy to survive. Protect with 6 to 12 inches of mulch for the winter to protect their root system.  One similarity hardy hibiscus have to tropical hibiscus is each of these will grow and blossom very well in pots.  They can add the perfect touch of color to the patio or flower.garden.  If you decide to place them in pots, wait until after the first frost to cut them back, then place in your garage or basement and water once a month. 

These big bloomers can be the highlight of your landscaping or flower garden.  E-mail us with any questions concerning hardy hibiscus