The species of Hibiscus and Hibiscus rosa - sinensis
The genus Hibiscus is one of more than a1150 genera of related shrubs and trees which belong to the Malvaceae-family. I just want to make a difference between the " wild " growing hibiscus species and Hibiscus rosa-sinensis, the first ones are very difficult to get at the nurserys but easy to grow from seeds.
The flowers and the growing habit of some hibiscus species are not very impressive, but I think there are quite a lot which are worth growing. First the ones which are herbaceous perennials. You can "forget" them in the basement during the wintertime, just giving them a drop of water from time to time : Hibiscus moscheutos hybrids like "Southern-Belle" , Hibiscus coccineus, Hibiscus laevis (synonym Hibiscus militaris), Hibiscus palustris and Hibiscus moscheutos "Galaxy". The " Galaxy " series is particularly interesting, as the plants can withstand freezing temperatures to -20° C and can therefor be planted in the garden.
The next one is Hibiscus paramutabilis and mutabilis. Those plants come from China, Taiwan and Japan. The leaves are velvety, the blooms of Hibiscus mutabilis change colour from pure white to dark pinkish during their flowering time. The plants can be overwintered at a warm place like a living room or in a cooler room. When keeping the plants in a cooler place they will shed the leaves there for they should be watered particularly careful. Grown from seeds and planted in the garden at a sheltered place, given some protection for the roots, the plants can withstand temperatures down to -15°C/5°F.
Hibiscus acetosella is especially beautiful with the red stem and leaves. The flowers appear in clumbs.
Hibiscus radiatus is as well grown best as an annual. The stem, the branches and the leaves are spiky. The flower is a light wine-red with darker venes and a dark red eye.
Hibiscus syriacus is the well known garden hibiscus, growing as shrubs to a considerable height, looking beautiful when grown as a hedge. They come in white, pink, wine-red and purple varieties, the blooms as singles, half doubles or full doubles, real eyecatchers in autumn.
There are several others which are well worth growing, some of them can be overwintered on the sill:
Hibiscus species and Hibiscus rosa-sinensis
Hibiscus arnottianus is one of the ancestors of our modern hybrids. It belongs to Hawaii and has a fragrance which is sometimes passed on to newer crosses.
Hibiscus asplenum has spreading branches, a small light red flower, the leaves are deeply lobed .
Hibiscus baptistii is growing slowly with thin branches and has a delicate red and white flower which looks sometimes “untidy”.
Hibiscus cooperi “Snow Queen” shows green with white leaves, the varieties “Rose Flake” or “Red Hot” show beside the white and green lots of red in their foliage.
The flowers of El Capitolio are red but there is a Sport which flowers orange and another one having cream coloured blooms.
The red flowering El Capitolio is a fast growing plant and therefore it is often used as rootstock.
Hibiscus schizopetalus is a strong growing species which needs in our colder climate a lot of heat and lots of fertilizer.
Hibiscus storckii originates from New Zealand and has a small apricot red with white windmill flower.
Hibiscus rosa-sinensis, also called "Rose of China" or "Queen of the Tropics" is commonly sold in supermarkets, nurseries and garden centers in springtime in white, red, yellow, orange or pink, some with a red eye zone, some are doubles. There are so much more beautiful hybrids given to us by hybridizers from the USA (Florida, Texas, California, Hawaii) Brazil, Tahiti, Taiwan, Australia and the Netherlands. Those hybridizers performed wonders in color combination, shape and size of the blooms.
In Germany there are many hibiscus enthusiasts which started crossing their varieties and the results are already remarkable.