Realm of Roses – An Introduction to Rosa

By Shelby Reynolds, GBG Friends Volunteer, Follow her here @little.cabin.life

 

A Brief History

Roses (Rosa L.) are a beautiful genus of plants that grow at Georgeson Botanical Garden. They have a long history that is deeply woven into the human experience. In fact, according to fossil evidence, the rose plant is approximately 35 million years old. Since that time, Rosa L. has grown to nearly 150 species which are spread throughout the northern hemisphere, from Alaska to North Africa. Rose cultivation began roughly 5,000 years ago, most likely in China. In the late eighteenth century cultivated roses were introduced to Europe from China. After this introduction, popular interest in the breeding and hybridization of roses led to the many varieties that exist today. 

Botanical Notes

Taxonomy:
Roses (genus Rosa L.) are from the Rosaceae family. The Rosaceae (rose family) consists of herbs, shrubs, and trees with roughly 3000 known species from 90 genera. There are several commonly known members including raspberries and blackberries (Rubus), plums, cherries, apricots, peaches nectarines, and almonds (Prunus), apples (Malus), quince (Cydonia), and of course, roses (Rosa).

Identification:
Rosaceae leaves are almost always deciduous and spirally whorled around the stem, although rarely they present opposite. In some of the woody plants within this family, sharp spines produce from the stem. This characteristic is typical of Rosa L., and are commonly known as thorns. The leaves of Rosaceae have serrated margins and can be simple or compound. The flowers of Rosaceae are radially symmetrical with sepals and petals presenting in series of five. 

Reproduction:
Rosaceae are monecious with the flowers containing both male and female reproductive parts. In roses (Rosa L.) the ovary is inferior – meaning it is positioned below the sepals and petals. The carpels are surrounded and fused to a hollow receptacle called the ‘floral cup’ or ‘hypanthium’. When pollinated, the rose (Rosa L.) ovary will turn into a fruit known as a ‘pseudocarp’, more commonly identified as a rose hip. 

Horticultural Notes

Classification:
The American Rose Society (ARS) classifies roses into three categories based on botanical and evolutionary progression. These include the Species (Wild) Roses, Old Garden Roses (OGRs), and Modern Roses. These classifications can help gardeners to navigate the variety of sizes, shapes, colors, blooming seasons, and maintenance of roses to find what best suits their garden.

  1. Species (Wild) Roses:

Species Roses, often referred to as “wild roses” are found naturally throughout the Northern Hemisphere. They are listed according to their Latin name, beginning with R. for Rosa and have common synonyms. An example is a Species Rose that is native to Fairbanks, Alaska – R. acicularis L. (meaning ‘needle-like rose’) – is more commonly known as the “Wild Prickly Rose”.

Species roses are hardy. They thrive on minimal maintenance and are fairly disease resistant. Species roses range in size and dimension from ground cover types to upright growers and climbers. Flowers of Species Roses are relatively simple with five petals. They can present as small clusters or large single blooms and vary in color from white to pink to crimson. Almost all Species Roses are once-blooming, which occurs in early summer. Their colorful hips will last well into the winter. Many rose enthusiasts include Species Roses in their garden for historical purposes as well as for their ease of maintenance. 

  1. Old Garden Roses (OGRs):

The American Rose Society defines Old Garden Roses as those types that existed prior to 1867. Within the broad categorization of Old Garden Roses, subdivisions exist based on natural historical developments as well as characteristics. The flowers of OGRs come in an array of shapes including quartered, cupped, imbricated or expanded, reflexed globular, or compact. The flowers bloom in early spring, with some varieties once-blooming. The greatest attraction to incorporating OGRs into a garden is their heavy fragrance.

The first subdivision of OGRs contains five classes of roses. They make up the most venerable group of cultivated roses. This includes Gallica, Alba, Damask, Centifolia, and Moss. They represent the hybrid roses that prevailed in European gardens prior to the introduction and trade of Rosa chinesis in the eighteenth century. They are cold-hardy, once-bloom roses that produce very fragrant flowers. 

  • Hybrid Gallica — Gallicas are the oldest roses, grown by Greeks and Romans, and were later bred by the Dutch and French. They are compact plants, just 3 to 4 feet tall. They can fill an area quickly by spreading through underground runners. Their foliage is roughly textured and dark green. They bloom once and come in an array of brilliant colors (including striped), with some that are intensely fragrant.

  • Alba — Alba date from before 100 A.D. Known as “white roses,” they have tall, slender upright growth – often climbing. They have dense, blue-green to grey-green foliage. They are disease resistant and can thrive under difficult conditions. Alba flowers are white or blush pink and richly perfumed.

  • Damask — Damasks are thousands of years old, and their introduction to European gardens is undetermined. It is said that the Crusaders introduced these roses to Europe from the Middle East. However, some believe the Romans brought Damasks to England. Yet a third claim is that Henry VIII’s physician presented him with a Damask rose around 1540. They are a tall plant that has an arching habitat of up to 7 feet. They are very thorny, extremely fragrant, and commonly used in perfume making. Their flowers are white, pink, or red. 

  • Centifolia — Meaning “hundred petals”, the Centifolia is commonly referred to as the “cabbage rose” due to the size and shape of its flowering head. These stunning roses are commonly featured in Dutch flower paintings of the 17th Century. They vary in size, growing in heights from 1 to 8 feet tall. They thrive in full sun and are very winter-hardy, but not as disease-resistant as others. The flowers of Centifolia often contain more than 100 petals and range in color from white to deep purple. They are once-blooming and very fragrant.

  • Moss — Known as the rose of Victorian England, Moss roses are named for the mossy thorn growth just below the sepals and calyx. This moss-like growth releases a pine-scented oleoresin when rubbed between the fingers. These plants grow 3 to 6 feet tall and are generally winter-hardy. Moss roses are very disease-resistant and tolerant of neglect, with some varieties that are repeat bloomers. 

The second subdivision of OGRs contains six classes which include Chinas, Bourbons, Hybrid Perpetuals, Noisettes, Portlands, and Teas. These are considered hardy OGRs, which can have extreme winter-hardiness, excellent tolerance to disease, stunning flowers, and powerful fragrance. Repeat blooms can be found in Bourbons, Portlands, and Hybrid Perpetuals.  

  • China — This class of rose is named for its origin, with original roses of this class brought from China to Europe. They were widely bred with other classes, resulting in repeat blooming plants that changed the Western world of roses. China roses are considered one of the most important historical groups of roses. They are variable in height, have relatively few thorns, and are disease-resistant. They are generally winter-tender and may need protection in cold climates – not surviving well below USDA zone 7. This plant blooms in small clusters that come in shades of copper and red. The flowers produce a sweet, fruity fragrance.

  • Hybrid China — These hybrids grow relatively small, ranging from 2 to 3 feet tall and are repeat bloomers. They are not hardy and require protection in cold climates. They bloom in clusters and produce a spicy fragrance. The stems of this plant are often to weak to support the cluster of blooms.

  • Bourbon — The name of this plan is derived from the location of the first members of this class, the Ile de Bourbon in the Indian Ocean. They were developed from Hybrid Chinas and are repeat-bloomers. Their growth habit is leggy, although some have a shrub form, and have a size range of 2 to 15 feet tall. Their large flowers often bloom in three to a cluster and are richly scented with rose fragrance.

  • Hybrid Perpetual — This class was popular in gardens of the 19th century. This plant has an upright arching growth of about 6 feet. This repeat bloomer produces large, double flowers that come in pink, purple, red, and sometimes white. The flowers possess a strong, delicious fragrance.

  • Noisette — This class originated in Charleston, South Carolina by Phillipe Noisette. They are the first roses bred in America with an ancestry that includes the China rose. Noisette introduced his rose to France when he moved there in 1817. These plants are large and sprawling – growing up to 20 feet tall – and should be treated as climbers with support. They tolerate clay soils. The flowers bloom in fragrant clusters and were the first class to introduce colors of orange and yellow.

  • Portland — Popular in the mid-1800s, Portlands have a mixed ancestry of China, Damask, Centifolia, and Hybrid Gallica roses. This class was named after the Duchess of Portland. They are relatively small, growing 4 feet tall with short peduncles. They are repeat bloomers that produce petite, multi-petaled, fragrant flowers that are usually pink with light green foliage.

  • Tea — Tea roses are a cross between Rosa chinesis and Rosa gigantea. Their growth pattern forms chunky, v-shaped shrubs that are well covered in foliage and flowers. Teas produce large blooms on weak stems, resulting in nodding flowers. Tea roses are disease-resistant. They grow slowly but will increase in size after two or three years. Pruning of this plant should be done lightly, as severe pruning can negatively impact the growth. Tea roses often have only five petals which are pastel or some shade of red. They are uniquely scented with a fragrance that reminds some people of tea.

  1. Modern Roses:

The era of modern roses officially began in 1867 with the introduction of the first-ever Hybrid Tea, ‘La France’, by the French breeder Jean-Baptiste Guillot. At the time, this variety was considered unique for several important horticultural reasons. First, this plant possessed the general habit of a Hybrid Perpetual while appearing with the elegantly shaped buds and free flowing flower character of a Tea rose. Breeders were quick to acknowledge that planned parenthood could produce new flower forms, size, growth habit, and colors. By the end of the 20th century, over 10,000 Hybrid Teas had been successfully bred. The most popular roses sold are Modern Roses. There are four commonly known classes of Modern rose – the Hybrid Tea, Floribunda, Grandiflora, and Miniatures.  

  • Hybrid Tea – Perhaps the most popular class of Modern roses, Hybrid Teas are easily recognized by their large, shapely blooms that contain 30 to 50 petals. These roses typically have long pointed buds that produce singular on a long stem. Occasionally they contain several sidebuds. The blooms come in a near endless pallet of colors, with only blue and black missing from this class. In exchange for the ‘perfect rose’, an incredible amount of inbreeding has robbed the Hybrid Teas of the disease-resistance, winter-hardiness, and other habits found in many of the OGRs. In fact, many Hybrid Teas no longer have a fragrance. This class of rose requires a spray program to maintain healthy foliage. 

 

  • Floribunda – This class was established when a Polyantha rose was crossed with a Hybrid Tea rose. The intention was to produce roses that are compact and have superior hardiness and disease-resistance – a habit that is lacking in Hybrid Teas. The American Rose Firm, Jackson and Perkins, introduced this class at the 1939 New York World’s Fair. Floribunda has a profuse ability to bear flowers in large clusters or trusses with more than one bloom in flower at any one time – meaning it is continually in bloom. They are often used as low hedges, borders, and in containers with other landscape plants. This class is unrivaled for its ability to produce massive, colorful, long-lasting garden displays. Floribundas are reliable in wet weather and are considered hardier and easier to care for than their Hybrid Tea counterparts. 

 

  • Grandiflora – The class “Grandiflora” was established in 1954 when a rose was developed from the cross between a Hybrid Tea rose and a Floribunda rose. This class carries its flowers in clusters on top of tall stems. This plant is one of the taller roses in the modern class and works well in the back of the border or as a screen. The blooms are usually double, with slightly larger flowers than Floribunda, but lack a striking fragrance. 

 

  • Miniatures – Miniature roses are small bushes with small flowers. They have enjoyed a remarkable increase in popularity over the years due to their novelty and versatility. They developed from a single dwarf China rose called “Rouletii”. Miniatures were popular with Chinese gardeners and were introduced to the United States when breeding programs started to blossom after World War II. The Miniature’s size makes it optimal for small gardens, edging beds, and growing in containers. They range in height from 3 to 18 inches and are extremely winter-hardy. Most are continuous bloomers with little-to-no fragrance.

    * “Miniflora” are a new classification established by the American Rose Society in 1999. This new class recognizes the intermediate bloom size and foliage falling between Miniature roses and Floribunda roses. 

 

Shrub Rose:

This subdivision of rose is a “catch all” for roses that are not easily categorized within the other classes. Shrub roses are noted for their well-rounded shape, their excellent winter-hardiness, and their above-average disease-resistance. They produce a decent amount of fragrant flowers throughout the summer.
These roses are typically bred to blend well into landscape hedges, mixed borders of flowers, and landscape at large – rather than in a rose garden.
Both Old and Modern Shrub roses have their merit. Old Shrub roses require a lot of space and can grow over 6 feet tall. They are extremely hardy and pest-resistant. Modern Shrub roses are compact, while still maintaining the qualities found in an Old Shrub rose. 


Stop and Smell Our Roses:

Georgeson Botanical Gardens has grown over 77 species of Rosa in our garden. One of the biggest joys of growing roses in the garden is the variation. Petals, flower structure, size, and foliage have evolved over centuries to offer a wide array of shapes and colors from plant to plant. When you walk our gardens, take note of the variety:

Rose Petals – Rose flowers can vary in their number of petals – some flowers can have as low as five, whereas others can have over 100. Petals even have their own architecture whether they are play or ruffled or frilled. The overall shape of the blossom has a diverse selection as well – rosette, pompon, open-cupped, quartered, flat, globular, and high centered. When you come to visit, how many petal variations can you spot between our roses? What shapes are the blooms?

Rose Color – Roses can be single, bi-color, multi-color, blended, and striped. They range in vibrancy from soft pastels to bold shades. Which rose from our garden is your favorite?

Foliage – It’s not just the petals that are pretty – take a peek at the foliage on our roses! Foliage surfaces can be matte, semi-glossy, or glossy and come in a spectrum of green shades. Some even have a bronze-tint. 

Sources:

American Rose Society (2018) Rose Classifications. Retrieved December 12, 2020 from https://www.rose.org/singlepost/2018/06/11/RoseClassifications#:~:text=The%20American%20Rose%20Society%20recen tly,not%20in%20existence%20before%201867).

 

Belle, E. (n.d.) Better Learning Through Botany: Rosaceae. Retrieved January 5, 2021 from https://williamettebotany.org/rosaceae-2/#_ftnref7

Martin, S. (2016) Heirloom or Old Garden Roses. Retrieved December 10, 2020 from http://piedmontmastergardeners.org/article/heirloom-or-old-garden-roses/#:~:text=The%20Old%20Garden%20Rose%20is,modern%20classes%20of%20this%20rose

Universisty of Illinois Extension (n.d.) Different Kinds of Roses. Retrieved December 10, 2020 from https://web.extension.illinois.edu/roses/kinds.cfm

University of Illinois Extension (n.d.) The History of Roses. Retrieved December 10, 2020 from https://web.extension.illinois.edu/roses/history.cfm

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