Hibiscus moscheutos also known as Rose mallow or Swamp Mallow is a cold-hardy perennial that grows in zones 4-9. The plant can grow up to 3-8 ft tall depending on cultivar and produces spectacular, dish plate sized, flowers 5-12″ wide that bloom in mid-summer until first frost. The large, showy flowers attract hummingbirds and butterflies.
Grow it in rich moist, well-drained soil with a ph 6.5-7.5. It will tolerate occasional wet soil. Hibiscus moscheutos can grow in full sun to part shade but blooms better in full sun. Fertilize in spring with a 10-10-10 . Mulch the plant during the dry summer to maintain even moisture. They should not be allowed to wilt. To prolong blooming time, deadhead flowers and remove seed pods.
When finished blooming allow the plant to dieback before cutting the stems 3″ above the ground or cut back in the spring. In cooler climates, Rose mallow will completely die back to the ground in winter, therefore mark the area where it was growing so that you know where to find it next season and mulch the area to protect the roots. It will return the following late spring but needs warm weather and long days to break dormancy. In cooler climates, it may not appear until June.
It can be started from seed. Soak the seeds overnight before planting. Start seeds indoors in late winter/early spring. Hybrid seeds will not come true but will revert to original plant. They can also be propagated from soft-wood tip cuttings in the spring or hard-wood cutting in fall as well as root division.
A new cultivar for this season is Cranberry Crush a deep red color.