Our hardy Hibiscus species as ornamentals
As a common plant name, "Hibiscus" is more often applied to the showy tropical sorts, especially Hibiscus rosa-sinensis L., than to other species of the genus. There is, however, another equally showy group, the hardy herbaceous mallows, native mostly to the Eastern United States. This group includes Hibiscus moscheutos L., H. militaris Cav., H. coccineus (Medicus) Walter, H. grandiflorus Michx., H. lasiocarpus Cav., and their many garden hybrids. The various species in this group are commonly called Rose Mallows. They grow naturally in marshy areas of the Atlantic States from southern New England to Florida, also inland along rivers and lakes. Isolated populations appear in areas such as the Sacramento River Valley of California. The tall vigorous growth of Rose Mallow plants plus the abundantly produced, large, gaily colored flowers makes them a conspicuous and attractive feature of the vegetation. Hibiscus moscheutos most often occurs in almost pure stands along tidal rivers of the mid-Atlantic states. During the peak of flowering, late July to mid-August, these stands are a striking sight to behold. In spite of the large fleshy roots, Rose Mallow plants withstand transplanting easily even when in full flower. They are also readily groxvn from seed and will flower the first season if sown early. Unlike their woody tropical relatives, the Rose Mallows are herbaceous perennials, and the plants become somewhat coarse by the end of the growing season. They also lack the yellow and orange flower colors so prominent in many Hibiscus rosa-sinensis clones. Nevertheless, the various species have been cultivated as ornamentals in the United States since Colonial times. As cultivated plants they perform best when grown in good garden soil with moderate amounts of water.
'Blue Angel' Winter-hardy Hibiscus (Hibiscus ·moscheutos L.)
Winter-hardy hibiscuses are herbaceous perennials in the mallow (Malvaceae) family that belong to six species native to the United States: H. coccineus Walter (scarlet rose mallow), H. dasycalyx S.F Blake and Shiller (Neches River rose mallow), H. grandiflorus Michx. (swamp rose mallow), H. laevis All. (halberdleaf rose mallow), H. lasiocarpos Cav. (hairy-seeded rose mallow), and H. moscheutos L. (crimsoneyed rose mallow) (Lawton, 2004; Winters, 1970). All species in the winterhardy hibiscus group have the same complement of chromosomes (2n = 38) (Klips, 1995) and hybridize relatively easily. They grow naturally in marshy habitats in the eastern part of the United States to southern Ontario (Canada) and in California (H. lasiocarpos). Winter-hardy hibiscuses, especially H. moscheutos and its hybrids, have attractive, tropical-looking flowers with a size of 5 to 30 cm in diameter. Winter-hardy hibiscus species are long-day plants (Warner and Erwin, 2001). All species of winter-hardy hibiscus are long-day plants (Warner and Erwin, 2001) that abundantly produce flowers from midsummer through late fall. The flowers last 1 d and colors range from white through pink to red, depending on the species. Recently developed cultivars of H. moscheutos such as ‘Fantasia’ (PP11,853) and ‘Plum Crazy’ (PP11,854) have lavender flowers. Breeders have also developed cultivars with different leaf shapes and colors and varying plant architecture. ‘Blue Angel’ has been released to provide a cultivar with a unique violet–blue flower color, which is not reported for winter-hardy hibiscus species.
The Tsetse Problem on the Eastern Cattle Route in the Gold Coast
1. Primary fly-belts round Makongo consisted of three different vegetational communities: a Cynometra-Vitex association along the main length of the Makongo river, on a clay soil; a Ficus congensis association along the river close to the town, on a sandy soil; and Isoberlinia doka woodland on moist sandy soil north-west and south of Makongo. 2. Secondary fly-belts of less dense vegetation occur in the orchard bush savannah round Makongo, and these are not colonised until the commencement of the rainy season. 3. Glossina tachinoides and G. palpalis both occurred in the riverside communities, and G. palpalis alone in the Isoberlinia woodland. 4. Along the river G. palpalis outnumbered G. tachinoides by 3:1 in the dry season. At the commencement of the rains G. tachinoides increased more quickly than G. palpalis , bringing their numbers very nearly equal, but at the end of the rains there was a decrease in G. tachinoides which restored the original proportion. 5. G. morsitans had been found at Makongo formerly but was not met with at the time of this investigation, its absence being due to the disappearance of the larger antelope from the neighbourhood. 6. Smaller game animals, small mammals and reptiles afforded an adequate food supply for tsetse in the fly-belts, and also passing herds of cattle, as well as natives from the village and travellers. 7. The distribution of G. palpalis within the fly-belts was markedly influenced by the proximity of a cattle road along which herds of cattle passed almost daily, and by village water-holes. 8. During the dry season the primary foci were always found to be the places of greatest relative humidity, and the fly does not tend to move out of these until the general atmospheric humidity has reached a certain fairly high degree. 9. In clearing the fly-belts the removal of all primary foci within a quarter of a mile of the town and of thick bush within 100 yards of water-holes was undertaken. The work lasted from the beginning of February to the end of March 1931. 10. The effect of clearing the Isoberlinia doka woodland was to banish G. palpalis completely, and it never returned to these clearings. 11. On clearing the riverside Ficus congensis fly-belt, G. tachinoides was practically eliminated for the first three months, but reappeared in the clearings in June when there was a general increase and up-stream migration of this fly. G. palpalis remained in this clearing in fluctuating numbers up to June, when observations were suspended. 12. 565 marked tsetse were liberated in the fly-belts immediately previous to clearing. Of G. palpalis 12·7% were recaptured in the clearings and 11% outside the clearings. Of G. tachinoides 5·5% were recaptured in the clearings and 6·8% outside.