According to Khosh-Khui and Jabbarzadeh (2009), the genus of rose (Rosa) belongs to the family of Rosaceae and includes up to four hundred of wild species, growing, in general, in the moderate zone. Some species grow in subtropical regions and even in the Arctic Circle. Taking into account the different climate and soil conditions, people wanted to get more new varieties of garden roses. Each new variety of a rose is a mixture of past and modernachievements and a new combination of petals, flower shapes and leaves, colors and aromas as well as the abundance and duration of the blossom. Not a single decorative culture has as many sorts as the rose has. The number of species and cultivals of rose has not been determined. The botanical characteristics of rose have not been studied enough and require a thorough investigation.
The basic life form of this plant is a deciduous or evergreen shrub or bush. Wild roses grow on their roots. The root system of wild roses is composed of the main tap root and side thinner roots. In the natural conditions, roses usually have a shape of a bush of varying height. If a rose is located near low plants, it will be smaller, with wide branches, and occupy quite a lot of space. If a rose is planted on the edge of a forest, or near high plants, the bush grows up and searches for light. In such conditions, the flowers are rare or do not appear at all. In such cases, the rose tries to penetrate the alien plants, and if it manages to do itso, the bush starts to blossom again. When planting the wild sorts of roses in a garden, they will keep their natural size and shape.
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However, in the gardens, people usually plant the cultivated roses. Pal (2007) notes that the modern varieties of this plant are the result of years of breeders’ work. The roses may be root-genuine, obtained as a result of propagation via the division of a bush. However, the majority of cultivated roses are grafted. It means that the cultivated roses were grafted on the bush of a wild rose.
The system of grafted roses has the main root that deepens into the soil and a number of side roots. On the endings of the side roots the beards that absorb water and nutritive elements are located. The skeleton roots are covered with a dark brown crust and serve as the nutrition system that brings the elements to the upper parts of the plant and fixes it in the soil. Moreover, the thick roots of a rose may store the nutritive components.
The botanical features of a wild rose are more developed than those of the cultivated one. In most cases, these are shrubs from 0.5 to 2.5 meters. However, some evergreen sorts may expand on more than 10 meters (R. Bansiae R., Br.: R. Wochuraiana Crep.). The wooden stems and shoots of roses are, as a rule, covered with spines, different in shape and size. The spines may be straight, curved, rounded, and flat. The leaf of most sorts consists of five to seven smaller leafs, but sometimes their number may be bigger (from nine to eleven).
According to Russell (2001), the flowers are bisexual, singular, located at the edges of branches or gathered into paniculate inflorescences. The flower may have up to eleven centimeters in diameter. Most of the sorts have five petals and sepals, but sometimes the number of petals is much bigger. The color of petals is usually white, pink or yellow, however, the cultivated roses may have different coloring. Numerous stamens and pistils are located on the thickened receptacle. Wild roses of most sorts flourish one time – at the end of spring or beginning of summer. The flowers appear on the shoots of the previous year.
Only the evergreen subtropical species (R. Chinensis Jacg, R. Bracteata wendl, R. Indica, R. Laevigate Mich, and others) bloom on new shoots throughout the summer with a few pauses. Like the evergreen species, many garden roses form the flowers on the new shoots.
Roses are pollinated with the help of insects, but the pollination by wind is also possible. Some species and varieties can form seeds without a pollination.
The real fruits of roses are the one-seeded nutlets with a dense woody shell, sometimes called seeds. False fruits that serve as a wrapper for the seeds are flat-round, round or oval, yellow to dark red, or even almost black receptacles. Such a fruit may contain from three to five, and even to 100 or more seeds.
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The rose fruit ripens in the middle of August or September. The development of plants from seed germination to fruiting lasts from three to five years. Some seeds of cultivated garden roses blossom in the first year, but most of the flowers appear on the second or the third year.
The root system of some species of the wild roses is very powerful and penetrates the soil to up to two meters (R. Canina L. R. rubrifalia Mill), the others spread their roots in the upper layers (R. Alpina L., R. rubiginosa L., R. Cinnamomea L.).
Many of the species of wild roses in the moderate zone are characterized by frost resistance. Their four to fiveyears old bushes can easily resist the temperatures down to -30° C. Some species can withstand the temperatures down to -50 ° C (R. davurica Pall, R. acicularis Lindl). Some evergreen species of roses from humid subtropical forests of Southeast Asia cannot resist frosts.
The garden roses of subtropical origin are heat-loving and light-requiring. They usually blossom only in the open, exposed to direct sunlight places, with an average daytime temperature of +18-20° C. In the shady places, even with a sufficient amount of heat, this sort of roses blossoms poorly. Roses of the subtropical origin very often do not have any explicit period of rest. These varieties sometimes may blossom and grow simultaneously.