Dan's Papers - August 24, 2007 - The Garden At Rock Cottage by Lance Brilliantine

A stroll through East Hampton this weekend showed that the perennial hibiscus is available in local nurseries. These dinner plate-sized blooms add a range of colors from white with crimson centers, to many shades of pink, lavender and red. With their displays of crepe paper-like flowers, these are truly one of the most beautiful of late summer perennials.

Cousin to the tropical hibiscus and Rose of Sharon, the perennial hibiscus is a garden favorite in the northeast. It provides a welcome contrast to the yellows and browns that begin to emerge in late summer. Despite the fact that the plant is a "late starter" in spring, it is one of the most dependable and easily grown perennials for East End gardens.

The perennial hibiscus (also known as Rose Mallow, Swamp Mallow, Dinner plate Hibiscus and Frisbee Hibiscus) displays the largest flowers of any perennial with blooms up to a foot in diameter. Plants begin blooming mid-July and may bloom through October. The blooms last for only one day, but the plant sends forth many buds that bloom sequentially, making them available for many weeks. The display, especially when planted in mass groupings, is quite dramatic.

The perennial hibiscus is a larger plant and requires space to spread. It is suitable for specimen plantings or large, singular groupings, or works well at the back of flower borders. The plant forms sturdy, erect, semi-woody stems and grows three to eight feet tall (pruning during the growing season will control height, provided the plants are not pruned later than the first week in July). Stalks spread out over a wide area - typically two to three feet. Leaves are large, gray-green in color, and ovate and pointed. Lower leaves can sometimes be three-lobed.

The perennial hibiscus is a member of the Malvaceae family of plants. The genus Hibiscus includes both tropical and temperate species. H. moscheutos, the perennial type, is a native perennial that typically grows in marshlands from Georgia to Texas. The plant survives well to Zone 5 and regenerates itself for many years (our experience suggests the plant does well for three or four years before needing replacement).

Hibiscuses have been hybridized since the early 1900s, and this has resulted in a number of widely popular hybrids that include H. coccineus, H. miliaris, and H. grandiflorus. Some of the most beautiful species of hibiscus include the following - "Aquarian," produces 12-inch blooms in lavender-pink; "Crown Jewel," develops a 10-inch bloom of white with maroon center; "Dreamcatcher," displays a 12-inch crepe-like pink; "Old Yella," offers a 12-inch, pale-yellow flower; and "Plum Crazy," a plum-shaded bloom of 10 inches.

Plants are readily available at this time of year from local nurseries and can also be mail ordered. Wittendales in East Hampton and Marders in Bridgehampton have some of the best collections.

Because the native perennial hibiscus grows naturally in swamps, marshes and ditches, it is adaptive to many garden situations where the plant will receive sun and water. We have found the plants grow best where they have moist, rich soil and are exposed to full sun. Copious watering and fertilizing throughout the growing season result in the largest stems, profuse blooms and vivid colors.

In fall, after the frost kills back the leaves, cut stems to about three inches above ground level. Cover the plant with a thick coating of mulch. Uncover the plants beginning mid-May, once the soil has warmed to about 50 degrees, and apply a good coating of organic fertilizer. The plant will send up new stems - usually beginning in June. Prune the stems once, but only after they have reached a height of 14 inches.

Perennial hibiscus holds special interest for the garden. Its large, crepe-like blooms make it a must for every late summer display.

You can contact Lance Brilliantine with any questions or comments at GardenLance@yahoo.com.