Rosa

This article is about the genus of flowers. For more uses of the word "Rosa", see Rosa (disambiguation).

"Rose" redirects here. For more uses of the word "rose", see Rose (disambiguation).

Rosa
A rose of the 'Amber Flush' cultivar.
Conservation status
Taxonomy
Kingdom	Plantae
Phylum/Division	Magnoliophyta
Class	Magnoliopsida
Order	Rosales
Family	Rosaceae
Subfamily	Rosoideae
Tribe	Roseae
Genus	Rosa
Naming and discovery
Botanist	L.

Latin pronunciation of Rosa

Rosa, known also as the roses, is a genus of perennial flowers, shrubs, or vines in the Rosaceae family. The genus contains over 100 species that come in several colors. These plants form a group of shrubs, with stems that have sharp prickles. Most are native to Asia, but some are found in other continents such as Europe, North America, and Africa. Cultivars and hybrids are often created due to the beauty of the flowers.

Leaves are alternate and pinnate. The plant's edible fruit, which ripens from summer to autumn, is known as a rose hip. The plants range in size, from miniature roses, to ones that can reach 7 meters in height. Species from different parts of the world make hybrids easily, which has given a wider variety of roses for gardening.

The name, rose comes from French, which was borrowed from the Latin rosa, borrowed by Oscan from the Greek ρόδιόν rhodion from the Old Persian word, wurdi "flower".

Attar of rose is a steam-extracted oil from roses, that have been used in perfumes for several centuries. Rose water, which is made from the oil is used in Asian cuisines. Rose syrup was made by the French, by extracting the liquid-like substance from the petals. The rose syrup is used to make rose scones and marshmallows.

Botany

Leaflets of a rose.

The leaves of most roses are 5-15 centimeters long, pinnate, with (3–) 5–9 (–13) leaflets and stipules. There are often a few small prickles on the stem under the leaf. Most roses are deciduous, but some in southeast Asia are evergreen.

The flowers of most species have 5 petals, with the exception of Rosa sericea, which usually has 4 petals. Each petal is divided into two lobes, and are usually white or pink, but occasionally are colored yellow or red. Beneath the petals are 5 sepals (in Rosa sericea there are 4).

The aggregate fruit of roses are a berry-like fruit called a rose hip. Species that have open-faced flowers are more likely to bring bees and other insects by, which will pollinate the flower, making more fruit. The fruit of most of these species are red, but some have dark purple to black hips. Each hip has an outer fleshy layer, called the hypanthium, which can contain 5–160 "seeds" (really achenes), embedded in fine stiff hairs. Some rose hips are very rich in vitamin C, such as Rosa canina (Dog Rose) and Rosa rugosa (Rugosa Rose). The hips are eaten by birds, such as thrushes, waxwings, and finches, and release the actual seeds in their droppings.

Rose "thorns" are actually prickles, outgrowths on the epidermis.

The sharp objects on rose stems, commonly called "thorns" are actually prickles, which are outgrowths on the epidermis. True thorns are produced by genera such as Citrus and Pyracantha. The prickles are shaped like sickle-shaped hooks, which help the rose hang onto other vegetation while it is growing. Some species such as Rosa rugosa and Rosa pimpinellifolia have densely packed straight prickles, probably used as an adaptation to reduce animals scavenging, or to trap blown sand to protect their roots. Despite having prickles, roses are often eaten by deer.

Species

A pink rose in India.

There are over 100 species of flowers in the Rosa genus. For the species in the genera, see List of Rosa species

Rosa is divided into four subgenera:

• Hulthemia (formerly Simplicifoliae, "with single leaves") contains two species from southwestern Asia, Rosa persica and Rosa berberifolia, which are the only roses without compound leaves and stipules.
• Hesperrhodos (from the Greek word for "western rose") contains Rosa minutifolia and Rosa stellata, from North America.
• Platyrhodon (from the Greek word for "flaky rose", referring to the flaky bark) contains one species from east Asia, Rosa roxburghii.
• Rosa - contains all the other roses. It is divided into 11 sections.
  • Banksianae - white and yellow flowered roses from China.
  • Bracteatae - consists of three species, one from India and two from China.
  • Caninae - pink and white flowered species from Asia, Europe, and North Africa.
  • Carolinae - white, pink, and bright pink flowered species from North America.
  • Chinensis - white, pink, yellow, red, and mixed-colored roses from China and Burma.
  • Gallicanae - pink to crimson and striped flowers from western Asia and Europe.
  • Gymnocarpae - one species in North America (Rosa gymnocarpa) and others in east Asia.
  • Laevigatae - one white flowered species from China.
  • Pimpinellifoliae - white, pink, bright yellow, mauve, and striped roses from Asia and Europe.
  • Rosa (syn. sect. Cinnamomeae) white, pink, lilac, mulberry, and red roses from everywhere but North Africa.
  • Synstylae - white, pink, and crimson roses from all areas.

Synonyms

• Hulthemia Dumort.
• ×Hulthemosa Juz.

Uses

Rose-picking in the Rose Valley near Kazanlak, Bulgaria. Engraving by traveller, Felix Philipp Kanitz.

Roses are best known as ornamental plants, which are displayed outdoors in gardens, and sometimes even indoors. They have also been used as commercial cut flower crops and used in the making of some perfumes. Some are used as landscape plants, and for hedging. Some roses are grown for scented foliage, ornamental thorns, or ornamental fruit. Roses also hold minor medicinal properties.

Cultivation

Main article: Garden roses

In horticulture, roses are propagated by grafting or rooting cuttings. Cultivars have been selected for flowers, growth habit, cold and/or disease resistant, and many other factors. Rose cultivars require 5 hours of direct sunlight each day during growing season. In winter, roses reach a dormant stage.

Thousands of rose hybrids and cultivars have been created, and selected to be used in gardening. In the early 1800's, Empress Joséphine de Beauharnais, the first wife of Napoleon Bonaparte patronized development of rose breeding in Malmaison. At 1840, a collection of 1,000 cultivars, varieties, and species may have been possible in Loddiges nursery in Abney Park Cemetery, a Victorian garden cemetery and arborteum in the United Kingdom.

Rose breeders of the 1900's mainly emphasized size and color, producing attractive flowers with little scent. By contrast, many wild and "old-fashion" roses have a strong scent.

Roses live mainly in temperate climates, and some in Asia can live in sub-tropical climates. Some species and cultivars can even live in tropical environments, especially when grafted onto proper rootstocks.

There isn't only one system for classifying garden roses, but in general, they are placed into one of three groups: Wild, Old Garden, and Modern Garden roses.

Cut flowers

A cut rose in a vase.

Roses are popularly used as domestic and commercial cut flowers. Usually, they are harvested and cut while budding, and then held in refrigerative conditions until they are ready for display at the point of sale.

In temperate climates, cut roses are usually grown in glasshouses, and in warmer climates, they may also be grown under cover to ensure the flowers are not damaged by weather and that pest and disease controls can be carried out effectively. Significant amounts of cut roses are grown in some tropical countries, and are shipped by air to markets all around the world.

Perfume

Main article: Rose oil

Rose oil from R. damascena.

Rose perfumes are made from attar of roses, which is a mixture of volatile essential oils obtained by distilling crushed petals of roses with steam. A similar product, rose water is used for cooking, cosmetics, medicine, and religious practices. The production technique originated in Persia, and then spread to Arabia and India, but recently, about 70 to 80% of production is in the Rose Valley near Kazanluk, Bulgaria, with some production in Qamsar in Iran and Germany. The Ka'aba in Mecca, Saudi Arabia is washed each year by the rose water from Qamsar. In Bulgaria, Iran, and Germany, damask roses (Rosa damascena 'Trigintipetala') are used. In France, the species, Rosa centifolia is used. The oil is transparent pale yellow or yellow-grey in color. 'Rose Absolute' is extracted with the solvent, hexane, and produces a darker oil, dark yellow to orange in color. The weight of extracted oil is about ³/₃₀₀₀ to ¹/₆₀₀₀ of the weight of the flowers; for example, about 2,000 flowers are needed to produce only one gram of oil.

The main components of attar of roses are the fragrant alcohols, geraniol and l-citronellol, along with rose camphor, an odorless paraffin. β-Damascenone is also a significant contributor to the oil's scent.

Rose hips

Hips of Rosa canina

The rose hip is used as a minor source of vitamin C. They are occasionally made into jam, jelly, and marmalade, or brewed in tea, mainly for their vitamin C content. They are also pressed and filtered to make rose hip syrup. Rose hips are also used to produce rose hip seed oil, which is used in some skin and makeup products.

Medicine

The fruits of many species contain significant levels of vitamins, particularly vitamin C, and have been used as a food supplement. Many rose species have been used in herbal and folk remedies. The China Rose (Rosa chinensis) has been used in Chinese traditional medicine. This, along with other species have been used for treating stomach problems, and are being investigated for controlling the growth of cancer.

Culture

Art

Pierre-Auguste Renoir's painting of cabbage roses (Rosa centifolia), Roses in a vase.

Rosa gallica, Evêque, painted by Pierre-Joseph Redouté

Roses are often portrayed by artists. Belgian artist, Pierre-Joseph Redouté produced some of the most detailed paintings of roses.

Henri Fantin-Latour was a painter of still life, particularly flowers. Cultivar, 'Fantin-Latour' was named after this artist.

Other impressionists, such as Claude Monet, Paul Cézanne, and Pierre-Auguste Renoir have also painted roses.

Symbolism

For more information, see Rose (symbolism)

The long cultural history of the rose has led to it being used sometimes as a symbol.

Quotes

Lots of famous quotes refer to roses:

• "What's in a name? That which we call a rose/By any other name would smell as sweet." – William Shakespeare, Romeo and Juliet, act II, sc. ii
• "Gather ye rosebuds while ye may,/Old Time is still a-flying" – Robert Herrick, To the Virgins, to Make Much of Time
• "O, my love's like a red, red rose/That's newly sprung in June" – Robert Burns, A Red, Red Rose
• "Information appears to stew out of me naturally, like the precious ottar of roses out of the otter." – Mark Twain, Roughing It
• "Hearts starve as well as bodies; give us bread, but give us roses." – James Oppenheim, "Bread and Roses"
• "Rose is a rose is a rose is a rose" – Gertrude Stein, Sacred Emily (1913), a poem included in Geography and Plays.
• "The optimist sees the rose and not its thorns; the pessimist stares at the thorns, oblivious to the rose" – Kahlil Gibran
• "'I love to see you at my table, Nick. You remind me of a- of a rose, an absolute rose.'" – Daisy Buchanan, The Great Gatsby by F. Scott Fitzgerald.

Pests and diseases

See List of rose diseases and Pests of roses

Roses are susceptible to a number of diseases, such as rose rust (Phragmidium mucronatum), rose black spot, and powdery mildew. Fungal diseases that the rose can obtain are best solved by a preventative fungicidal spray program rather than trying to cure an infection that has already occured. After the disease is visible, its spread can be minimized through pruning and fungicides, although the infection itself cannot be reversed. Certain rose varieties are less susceptible than others to fungal diseases.

The main pest that affects roses is the aphid (subfamily Apidoidea), which sucks the plant's sap and weakens it. Ladybugs (family Coccinellidae) are predators of aphids, and are encouraged in a rose garden. In the areas where they are endemic, Japanese beetles (Popillia japonica) takes a heavy toll on rose flowers and foliage; thrips (Thysanoptera sp.) can also be harmful to roses. Roses are also used as food plants for the larvae of some Lepidoptera (butterfly and moth) species; see list of Lepidoptera that feed on roses. Spraying roses with insecticides is often recommended, but should be done with care to minimize the loss of beneficial insects.

See also

• Cultivar
• Garden roses
• Rose cultivars

External links

• Rose on Wikipedia