Chiba University Matsudo/Kashiwa Campus Plant Database

Details of genus: Rosa L. [242]

genus_ja: バラ

genus_en: Rose

# spp.: 268

pub_year: 1753

accepted: Accepted

Family: Rosaceae

family_ja: バラ

Infra familial classification: Subfamily Rosoideae: Tribe Roseae

distribution_en: Temp. & Subtropical Northern Hemisphere

description_en: Genus of about 150 species of semi-evergreen or deciduous, perennial shrubs and climbers, some of which have been in cultivation for many centuries. They are found in a wide variety of habitats in Asia, Europe, N. Africa, and North America. Roses have erect, arching, scrambling, or sometimes trailing, often thorny or prickly stems. The alternate leaves range from 2.5cm (1in) long in miniature roses to 18cm (7in) or more long in bush, shrub, and climbing roses; each leaf usually has 5 or 7 sometimes toothed, variably shaped leaflets. Roses are grown for their attractive and often very fragrant flowers, borne mainly in summer and autumn, and sometimes also for their fruits, known as hips. The flowers are solitary or borne in corymbs (referred to in this account as clusters), are sometimes remontant, and vary greatly in colour, size, and form (see panel below) . Roses are suitable for a range of garden situations: as specimen plants or standards, for a shrub or mixed border, as hedges, or as climbers to clothe walls, trees, pillars, pergolas, and arbours. Groups of roses are often grown together in a single bed; a well-chosen mix of cultivars will ensure a long summer display. Miniature roses are suitable for a rock garden, raised bed, or containers. The flowers of all roses are popular for cutting. Many modern rose cultivars are known by their trademark names rather than by their registered cultivar names; where this is the case, the plant is listed below under its trademark name, with the cultivar name given as a synonym. For reasons of space, these cultivar names have not been cross-referenced. Rose species and cultivars are often regarded as 2 separate groups. Cultivars are further divided into Old Garden and Modern roses, the many subgroups of which are described below. Species, or wild, roses (including inter-specific hybrids, which share most of the characteristics of their parent species) are either shrubs or climbers, mostly bearing single, 5-petalled, often fragrant flowers in early summer, usually in one flush on short shoots from second-year wood; the flowers are followed by red or black hips. Cultivars, derived initially from crossing species roses, number many thousands, and are very varied in habit. In the subgroup descriptions below, leaflet lengths are defined as: small, up to 4cm (1 1/2in); medium-sized, 4-7cm (1 1/2-3in); large, over 7cm (3in). The flowers, in a range of shapes, are borne mainly in summer, over a longer period than in species roses; they are often remontant. Flowers are either single (having 8 petals or fewer), semi-double (8-20 petals), double (20 petals or more), or fully double (over 30 petals). "Single to fully double", as used below, means that the flowers may be single, semi-double, double, or fully double.

hardiness_en: Fully hardy to frost hardy.

cultivation_en:

propagation_en: Root hardwood cuttings in autumn. Bud in summer.

pests_en: Susceptible to aphids, leafhoppers, red spider mites, scale insects, caterpillars, sawfly larvae, and leaf-cutting bees; rabbits and deer may cause damage. Prone to black spot, rust, powdery mildew, die-back, canker, crown gall, honey fungus, soil sickness, viruses, and downy mildew.

description_ja:

comment:

comment_ja: バラ，ハマナス

type_species:

Phylogenetic definition:

Update Information: Created: 2007-12-06 12:51; Updated: 2023-07-14 14:06 by hkokubun@mac.com

family: