Garden roses

Garden roses are predominantly hybrid roses that are grown as ornamental plants in private or public gardens. They are one of the most popular and widely cultivated groups of flowering plants, especially in temperate climates. An enormous number of garden cultivars has been produced, especially over the last two centuries, though roses have been known in the garden for millennia beforehand. While most garden roses are grown for their flowers, often in dedicated rose gardens, some are also valued for other reasons, such as having ornamental fruit, providing ground cover, or for hedging.
The cultivars are classified in a number of different and overlapping ways, generally without much reference to strict botanical principles. Taking overall size and shape, the most common type is the bush rose, a rounded plant from 2 foot up to about 7 foot tall, above which height roses generally fall into the "'climbing and rambling'" class, the latter spreading wider; support is needed for these. There are also miniature roses, generally small bushes, and low sprawling ground cover roses, both up to about 15 inches tall. Most modern roses are propagated by budding onto rootstocks much closer to wild species; in "standard" shapes there is a single bare stem, with the graft at the top of that. Shrub roses are a rather loose category that include some of the original species and cultivars closely related to them, plus cultivars that grow rather larger than most bush roses. Technically all roses are shrubs. In terms of ancestry, roses are often divided into three main groups: Wild, Old Garden, and Modern Garden roses, with many subdivisions of these.
Gardeners most value roses for their large and brightly coloured flowers, which exist in every colour in the white to yellow to red part of the colour spectrum. A truly blue rose has yet to be bred, but there are a number of shades of purple. There are single or double-flowered varieties, with the latter much more popular. The petals are typically of a single colour, although bi-colour, striped and blended varieties exist. The classic hybrid tea rose flower shape, pointing up, tightly curled in the centre, with the outer petals spreading wide, is the most popular for gardens, and even more dominant in florists. But there are many alternatives. Most of the wild parent species are single-flowered with flat blooms, flowering only once, and many are still grown in gardens. Most varieties produce a single flower on a stem, but floribunda roses, introduced in the early 20th century, have a spray of several flowers, and are highly popular; they also have more continuous flowering. Most garden varieties still have thorns, though fewer than those in wild species, but some are thornless. It is often complained that modern varieties are deficient in scent from the flowers, and many are. An important development in recent decades has been extending the flowering season, in some cases to eight months in the right conditions, though the flower display still tends to be best in one or two "flushes", the first in late spring.
File:Rose Garden View in Ooty, Tamil Nadu.JPG|thumb|The Government Rose Garden, Ooty in South India; in the Tropic of Cancer, but at an altitude of 2200 metres
File:Rose Garden at Huntington Library in Pasadena, California. April 2022 20220418 160351.jpg|thumb|Rose Garden with variety of blooming roses at Huntington Library in San Marino, California, United States, April 2022
Roses are relatively easy to grow compared to many large-flowered garden plants, with the main effort, apart from basic watering and feeding, going into the pruning that most varieties need, and the training that many do. At least bush varieties are usually deadheaded, although some varieties are left for their decorative rosehips. Roses are successfully grown in four continents, although a tropical climate is not ideal.
File:Blooming roses at Huntington Library in Pasadena, California. April 2022 20220418 160140.jpg|thumb|Blooming Roses at Huntington Library in San Marino, California, United States, April 2022

History

Origins

Roses have been grown in Eurasia since ancient times; they appear in Minoan jewellery and frescos from before 1400 BC, and in Egyptian tomb paintings some centuries later; however the Bible only mentions the plant twice. They are known to have been grown in ancient Babylon. Records exist of them being grown in Chinese gardens and Greek gardens from at least 500 BC, and the ancient Romans were extremely fond of them, putting rose petals in beds, and throwing them at festive occasions. They remained popular in Islamic and Chinese gardens.
Most of the plants grown in these early gardens are likely to have been species collected from the wild. However, there were large numbers of selected varieties being grown from early times; for instance numerous selections or cultivars of the China rose were in cultivation in China in the first millennium AD.
Of the over 150 species of rose, the Chinese Rosa chinensis has contributed most to today's garden roses; it has been bred into garden varieties for about 1,000 years in China, and over 200 in Europe. Among the old Chinese garden roses, the Old Blush group is the most primitive, while newer groups are the most diverse.
The significant breeding of modern times started slowly in Europe, from about the 17th century. This was encouraged by the introduction of new species, and especially by the introduction of the China rose into Europe in the 19th century. An enormous range of roses has been bred since then. A major contributor in the early 19th century was Empress Josephine of France who patronized the development of rose breeding at her gardens at Malmaison. As long ago as 1840 a collection numbering over one thousand different cultivars, varieties and species was possible when a rosarium was planted by Loddiges nursery for Abney Park Cemetery, an early Victorian garden cemetery and arboretum in England.
Although roses were found in modern-day Colorado from about 50 million years ago, the relatively few species native to the Americas have made almost no contribution to the parentage of garden rose hybrids.

Features

Roses are one of the most popular garden shrubs in the world with both indoor and outdoor appeal. They possess a number of general features that cause growers and gardeners to choose roses for their gardens. This includes the wide range of colours they are available in; the generally large size of flower, larger than most flowers in temperate regions; the variety of size and shape; the wide variety of species and cultivars that freely hybridize.

Colour of flowers

Rose flowers have historically been cultivated in a diverse number of colours ranging in intensity and hue; they are also available in countless combinations of colours which result in multicoloured flowers. Breeders have been able to widen this range through all the options available with the range of pigments in the species. This gives us yellow, orange, pink, red, white and many combinations of these colours. However, they lack the blue pigment that would give a true purple or blue colour and until the 21st century all true blue flowers were created using some form of dye. Now, through genetic modification, a Japanese company succeeded in creating a blue rose in 2004. Colours are bred through plant breeding programs which have existed for a long time. Roses are often bred for new and intriguing colour combinations which can fetch premium prices in market.

Classification

There is no single system of classification for garden roses. In general, however, roses are placed in one of three main groups: Wild, Old Garden, and Modern Garden roses. The latter two groups are usually subdivided further according to hybrid lineage, although due to the complex ancestry of most rose hybrids, such distinctions can be imprecise. Growth habit and floral form are also used as means of classification. This is the most common method to classify roses as it reflects their growth habits.

Wild roses

Wild roses, also denominated "species roses", include the natural species and some of their immediate hybrid descendants. The wild roses commonly grown in gardens include Rosa moschata, Rosa banksiae, Rosa pimpinellifolia, Rosa rubiginosa, and Rosa foetida in varieties 'Austrian Copper', 'Persian Double', and 'Harison's Yellow'. For most of these, the plants found in cultivation are often selected clones that are propagated vegetatively. Wild roses are low-maintenance shrubs in comparison to other garden roses, and they usually tolerate poor soil and some shade. They generally have only one flush of blooms per year, described as being "non-remontant", unlike remontant, modern roses. Some species have colorful hips in autumn, e. g. Rosa moyesii, or have colourful autumnal foliage, e. g. Rosa virginiana.

Old garden roses

An old garden rose is defined as any rose belonging to a class which existed before the introduction of the first modern rose, La France, in 1867. Alternative terms for this group include heritage and historic roses. In general, Old Garden roses of European or Mediterranean origin are once-blooming woody shrubs, with notably fragrant, double-flowered blooms primarily in shades of white, pink and crimson-red. The shrubs' foliage tends to be highly disease-resistant, and they generally bloom only from canes which formed in previous years. The introduction of China and Tea roses from East Asia around 1800 led to new classes of Old Garden Roses which bloom on new growth, often repeatedly from spring to fall. Most Old Garden Roses are classified into one of the following groups.

Alba Rosa

Literally "white roses", derived from R. arvensis and the closely allied R. × alba. The latter species is a hybrid of R. gallica and R. canina. This group contains some of the oldest garden roses. The shrubs flower once yearly in the spring or early summer with scented blossoms of white or pale pink. They frequently have gray-green foliage and a vigorous or climbing habit of growth. Examples are 'Alba Semiplena', 'White Rose of York'.