Author: RNDr. Jiri Zlebcik
Roses are deciduous, rarely evergreen woody plants. The whole family Rosaceae is named after them. They can be low or tall shrubs; sometimes weeping, procumbent or leaning against neighboring woody plants which gives them liana like character. Canes can reach from 5m length in our climate to even 20m in subtropical.
Their root system has a distinctive taproot, but some roses complement it with shallow rooting runners (Rosa pimpinellifolia, Burnet Rose).
Branches and twigs have thorns, but there are few exceptions. Thorns, which can break, are different according to a species in shape, size and density on canes. They can be all the same or varied a lot. There are also types with soft conifer-like or brushy spines, which can be very unpleasant to touch (Rosa rugosa, Rugosa Rose).
Leaves are alternating with dentate rim, ending with a single leave – odd pinnate, mostly pentamerous, sometimes hairy or glandular. Mostly permanent stipules grow directly on leaf stalk.
Flowers are androgynous with a lot of stamens, having a bowel shape in cases of original botanical species and they are single or in poor (rarely rich) inflorescences. Flower size of wild roses varies from 2 to 10cm. Five (rarely 4) petals are of an egg shape, often bilobed. Colors of wild rose flowers are mostly pink in all shades, pure white or purple-red, only a few species are yellow.
Fruit called rose hip (hypanthium) of original species can have considerate shape diversity. It can be round, egg-shaped or long oval in a size from 5-50mm. Its color is predominantly red, rarely black, orange or yellow. Rose hips are filled with small downy achenes.
Distribution of Roses
Wild roses grow basically all around the northern Hemisphere, except arctic or desert areas of course. They can grow even in mountains of subtropical and tropical climate (Ethiopia, Philippines). Areas with the richest number of species are Mediterranean and east Asia, on the contrary only very little roses grow naturally in Scandinavia, Island, Canada or Siberia, where these species cross the Arctic Circle. The most of roses come from the Old Continent, only about 20 species are from North America and these didn’t participate in origins of cultural roses.
There are 13 wild roses in the Czech Republic. Field Rose (Rosa arvensis) is considered extinct for this area. They can be found almost everywhere, but the most roses grow in warn lowlands or uplands. Which means in a landscape with a lot of disperse vegetation like hedgerows, balks, forest edges and places with extensive agriculture.
The most thermophilic Burnet Rose (Rosa spinosissima, syn. R. pimpinellifolia) grows in dry forest steppe slopes. On the other hand there are two hydrophilous species: Mountain Rose (Rosa pendulina, syn. R. alpina) and Cinnamon Rose (Rosa majalis) occuring in colder and mountain areas. The most abundant and widespread species is Dog Rose (Rosa canina).
According to different attitude of botanists there are 100 – 300 species of roses described. Definition of some species can be difficult in terms of great morphologic variability and it requires to compare not only flowers, leaves, thorns and rose hips but also sepals after blooming or sterile canes of relative species. Some species can be considered as lower taxonomic unit like sub-species, or inter-species hybrids figure as separate species.
Genus Rosa is divided into 4 sub-genera, 3 of them have just small significance, because most of the species belong to Rosa (also Eurosa) sub-genus. This one is further divided in 10 sections. We will mention only the most significant species, which means the ones we can find in the wild of Czech Rep. or which are often grown in gardens and parks
Caninae Section (60 species alltogether)
· Dog Rose (Rosa canina) and its relative species, distribution in Europe, north Africa, and west Asia
· Redleaf Rose (Rosa glauca, syn. R. rubrifolia), south and central Europe
· Apple rose (Rosa villosa, syn. R. pomifera), north and central Europe
Cinnamomeae Section (85 species)
· Cinnamon Rose (Rosa majalis), north and central Europe
· Mountain Rose (Rosa pendulina, syn. R. alpina), north and central Europe
· Rugosa Rose (Rosa rugosa), east Asia
Gallicanae Section (1 species)
· Gallic Rose, French Rose, or Rose of Province and its hybrid species (Rosa gallica), south and central Europe, west Asia
Indiceae Section (3 species)
· Manipur wild-tea rose (Rosa gigantea), India
· China Rose(Rosa chinensis) synonym to Cyme Rose (R. indica), China
· They are elementary species for breeding of roses
Pimpinellifoliae Section (15 species)
· Austrian briar, Persian yellow rose, and Austrian copper rose (Rosa foetida, syn. R. lutea), Asia Minor
· Father Hugo Rose (Rosa hugonis), central China
· Burnet Rose (Rosa spinosissima, syn. R. pimpinellifolia), west, central and south Europe, west Asia
Synstylae Section (30 species)
· Multiflora rose or Japanese rose (Rosa multiflora), Japan and Korea