Here are some easy tips on how to grow Hardy Hibiscus plants: These hardy, fast-growing herbaceous perennials do best in moist soil rich in organic matter. But they will also grow in average medium to wet soil. Soil pH should be 6 to 7. Hardy Hibiscus plants like full sunlight and good air circulation. They need regular, deep watering. They do not need staking. Avoid windy locations to guard from windburn.
Botanical Name: Hibiscus moscheutos
Common Name: Rose Mallow
Propagation: Division of woody crown is challenging and best avoided.
Description: These tropical flowering plants grow 3 to 8 ft. tall and 5 ft. wide. Hardy Hibiscus plants only stay green year-round in areas without frost. These perennial plants have red, white, pink, or bicolored blooms and triangular leaves with saw-tooth notches. They bloom late (July) and right up to frost.
Origin: Native of USA swamps, marshes, and stream banks
USDA Zones: 4 – 9
Fertilizer Needs: Fertilize early spring, late spring, mid-summer, and late fall with Espoma Palm-tone.
Maintenance: Low. Similar to daylilies, Rose Mallow flowers last only one day, then turn to mush and clump together. Deadhead before this happens. Stems need to be cut down in the late fall for new spring growth. Hardy hibiscus responds to pruning before flowering to create fuller plants. This may also help avoid early Japanese beetle damage.
Water Needs: In the first growth season, follow a regular schedule to set deep roots. Afterwards, regular moderate watering will do. In extreme heat, water more often; if soil dries out, leaf scorch sets in.
Display: Great choice for rain gardens, in borders or large pots
Wildlife Value: Deer resistant; attracts butterflies and hummingbirds
Pests/Diseases: Japanese beetle, aphid, whitefly