Thursday, December 17, 2009

Hibiscus lasiocarpos

Hibiscus lasiocarpos | Hairy-fruited Hibiscus, Hairy-fruited Rose Mallow, Hairy Rose Mallow, Downy Rose Mallow, California Hibiscus, Delta Hibiscus, Sacramento Rose Mallow, River Mallow, Woolly Rose Mallow

As a common name, Hibiscus is more often applied to the showy tropical types, such as the Hibiscus rosa-sinensis cultivars. There is, however, another equally showy group of hardy, herbaceous, perennial Hibiscus, native to North America ―Hibiscus section Muenchhusia, composed of a number of closely related species that are mainly confined to marshy habitats (edges and banks of ponds, lakes, ditches, and streams, and low wet wooded areas) in the eastern U.S. These are collectively referred to as 'Rose Mallows' or 'Swamp Mallows'. The Muenchhusia species are: Hibiscus coccineus, Hibiscus dasycalyx, Hibiscus grandiflorus, Hibiscus laevis, Hibiscus moscheutos, Hibiscus lasiocarpos and Hibiscus palustris. Both Hibiscus lasiocarpos and Hibiscus palustris can be split from Hibiscus moscheutos, and are sometimes ranked as subspecies or varieties.

Hibiscus section Muenchhusia: Within section Muenchhusia, there are numerous naturally occuring forms as well as flower colors, ranging from pure white to deep red. Additionally, many cultivars have been released through the years into the nursery trade. In cultivation these species, cultivars and hybrids make an attractive addition to the garden, not only adding visual appeal but also enhancing wildlife value for nectar-feeders and birds. But it now looks like a new era of hybridizing has begun for the cold-hardy Swamp Mallow family. For more infomation, see the following article: "A Blue Flowering Winter-hardy Hibiscus".

Due to range overlap and resultant intergraded forms, there is ongoing discussion as to whether Hibiscus lasiocarpos (along with Hibiscus palustris) merit species status. It appears that the eastern, glabrous-fruited Hibiscus moscheutos is distributed from New Hampshire to Florida and westward, where it gives way to (and intergrades with) the more western pubescent-fruited Hibiscus lasiocarpus. Hibiscus lasiocarpos is also identified with the following basionyms: Hibiscus moscheutos ssp. lasiocarpos and Hibiscus moscheutos var. lasiocarpos.

Hibiscus lasiocarpos is a bushy perennial with multiple sprawling stems up to 2m long, with a height of approximately 4’ tall. Cutting the plant back in late spring results in shorter plants with larger flowers. The heart-shaped, usually pubescent leaves, are generally between 6 and 10 cm long. This species can be quite variable in its pubescence, with some plants almost completely glabrous while others growing in the same location are densely pubescent. The subtly fragrant flowers are large and showy, commanding attention when in full bloom (usually August through September). The inflorescence holds solitary flowers, usually cream to white colored (sometimes tinged with pink ), with a deep maroon eye, and petals up to 10cm long.

As implied by its many common names, Hibiscus lasiocarpos (sometimes also spelled Hibiscus lasiocarpus), has a wide distribution ranging from California and parts of northern Mexico, to much of the southeastern U.S. In the wild, Hibiscus lasiocarpos occurs along stream banks and freshwater marshes. It makes an excellent subject for bog gardens due to its ability to tolerate constantly wet soil. Young plants should be kept evenly moist, however older, established plants can be watered less frequently. During winter, Hibiscus lasiocarpos dies back to the roots, so it does not require much watering during this time, unless you are in a particularly arid climate.

In California, this native Hibiscus can be found growing in damp areas along the Sacramento River Delta. Threatened by riverbank alteration and loss of habitat, it is classified by the California Native Plant Society (CNPS) as List 2, meaning that it is rare, threatened or endangered in California, but more common elsewhere. In California, Hibiscus lasiocarpus has been through a variety of name changes including: Hibiscus californicus Kell 1873, Hibiscus moscheutos var. occidentals 1874, Hibiscus lasiocarpus var. occidentalis Gray 1887, Hibiscus lasiocarpus var. occidentalis Bailey 1915.

Historical Reference: Hibiscus lasiocarpus. Very similar to Hibiscus moscheutos, with broadly ovate leaves, more or less cordate at the base, nearly equally tomentose on both sides. Bracts of the incolucre ciliate. Flowers as in Hibiscus moscheutos. Capsule more or less densely hairy. [The form figured at the above place is the var. occidentalis, Gray, from Mexico and California, which differs in having the leaves more uniformly cordate at the base, and the capsule pubescent rather than hirstute.] North America.

   List of published names of plants introduced to cultivation: 1876 to 1896
   Royal Botanic Gardens, Kew