Hibiscus x 'BALTIMORE STAR' swamp mallow, hardy hibiscus

Swamp mallow and its hybrids have been sought after plants for the past few years now. They are perennials with sturdy stems that have large, tropically looking flowers. Baltimore Star is a modern variety which did not arise from the original crossbreeding between h.moscheutos and h.coccineus. This variety is a cross between finished hybrids.

Baltimore Star has large flowers of amazing, deep red colour as in varieties Lord Baltimore and Fireball. However, Baltimore Star is earliest of all red-flowering hardy hibiscus known so far – you can spot first opened buds in late July. They continue blooming until the first really cold days of autumn. This variety produces attractive foliage, too. The leaves are 3-lobed, rich burgundy red when they emerge, keeping this shade until early summer, and just before the plant starts blooming they change to dark olive green with purple overlay. In late September they turn golden yellow, orange, and scarlet red before they fall down.

The plant is dependent on regular watering and feed supply. Use fertilizers with enough phosphorus for abundant flowering, or any other quick-release fertilizers where nitrogen is not predominant. Any fertilizing has to stop by end September. Still, nitrogen-based fertilizer is useful when the plants wakes up from dormancy in mid spring, but should not be used longer than 8 weeks. Hardy hibiscus emerges very late, sometimes as late as in late May.

For healthy growth and profuse flowering it needs a sunny location with a lot of moisture which can be achieved by good mulching. The soil has to be fertile and permeable, never let it dry out in summer. Hardy to about -29°C (USDA zone 5). Cut back the plant only a few centimetres above ground level in spring.

Last update 06-08-2012