Neil Sperry

Everything you need to know about one of Neil Sperry’s favorite plants — hardy hibiscus

As a husband, dad and grandpa, I can now safely admit that I was an odd kid. By the time I was 11 or 12, I was falling asleep dreaming of flowers I wanted to plant and tropicals I wanted to try. Odd plants excited me, and I just figured I’d never have the chance to grow many of them.

Well, I was wrong. I got those rare really red and nearly black daylilies. I grew big staghorn ferns. I found (and still have) hundreds of types of haworthias, and I even have one of the most dazzling flowering tropicals of all — a beautiful Brugmansia, with its 12-inch, downward-hanging blooms that open at night. And the list goes on and on.

But one of my favorite plants of them all has become so mainstream now that everyone can enjoy it. Hardy hibiscus, also commonly known as “rose mallow,” is a staple item in perennial gardens all over the world, and most of that has come in my lifetime.

The early collection I grew was known as Southern Belle and it came only as mixed colors. They grew to be 4 to 5 feet tall and wide, and they produced huge single flowers up to 6 to 8 inches across in shades of rose-red, pink and white, many with contrasting red centers (“eyes”).

Due to the plants’ height, they had to be grown in the backs of the perennial garden, or you could actually grow them as free-standing clumps out in the landscape. You had to allow for them to die to the ground in the winter, but you knew they would sprout out again the following spring to start the whole process over again. After all, they’re winter-hardy clear to the Great Lakes and beyond. Their flowers lasted only one day, but there were always more coming along to fill in the voids, and all of that remains true with today’s modern hybrids.

Speaking of those hybrids, the breeders got busy improving these hardy hibiscus. They already had good flower size and colors, but they wanted to reduce the size of the plants. So along came the shorter, award-winning Disco Belle series, and for many years they remained the state of the art.

In the past 25 or 30 years, however, hybridizers have been busy trying to find still shorter selections that will bring us great flower size, the wide range of colors, and maybe some ruffling or even a hint toward double blooms. And all of that is working.

And now, enter the maroon hues into the leaves. We now have a nice range of varieties that sport showy maroon-green leaves beneath rich red, pink and white blooms. These modern hybrids put on quite a show. Many of the industry awards for outstanding perennials are being claimed in the names of these plants and the hybridizers who have brought them to us.

How best to succeed with hardy hibiscus

If you’d like to try your hand at growing these heat-loving beauties that are quite mannerly alongside garden pools, here are your keys to success:

  • Full or nearly full sun (8 or more hours of direct sunlight in summer);
  • Moist, highly organic, well-draining soil;
  • Ample space (3 feet from other perennials) even though you’ll have a smaller plant now at maturity with the newer varieties; and
  • High-nitrogen fertilizer to promote vigorous growth, along with consistent supply of moisture. (Mallows grow in boggy soils, often in roadside ditches, in their native homes.)

Other close relatives:

Texas Star hardy hibiscus: This one has very different leaves that are highly incised and pointed. It has bright red 5-inch blooms.

Confederate rose: Given consistent moisture and ample space to grow, this will grow to be a very large plant (8 or 10 feet tall and wide). Its flowers are soft pink and double, looking very much like a fluffy rose. Like the other hardy hibiscus, it freezes to the ground and comes back from its roots.

Rose-of-Sharon, or althaea: This plant is a woody shrub that’s extremely winter-hardy clear into Canada. Its single and double flowers come in shades of lavender, white, pink, rose and combinations of all of them. It blooms all summer, but most heavily in June and into July. It’s deciduous, but it does not die to the ground in the winter. Mature heights vary with variety, ranging from 6 to 15 feet.

Pavonia, or rock rose: This is the diminutive sister of the family. Its flowers look like it belongs here, but the plant grows with much more refinement. Maximum height: 24 to 30 inches. Flower colors center mostly around pink, whitish-pink and rosy-pink.

You can hear Neil Sperry on KLIF 570AM on Saturday afternoons 1-3 pm and on WBAP 820AM Sunday mornings 8-10 am. Join him at and follow him on Facebook.

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