
With over 300 species and nearly 20,000 cultivars of roses to choose from, it’s easy to understand why it’s helpful to categorize them according to their most obvious traits. Source: T.Kiya, Wikipedia Commons
Confused about rose classification? Is that rose a hybrid tea or a floribunda? Or perhaps an old garden rose? If you’re lost, here are a few quick and easy pointers to point you in the right direction: just the right thing to bone up on before you head to the Rose Show!
Rose Classification
There is no single system of classification for garden roses. Pretty much every rose society has its own. In general, however, roses grown commercially these days are placed in one of the following categories:
1. WILD or SPECIES ROSES

If the rose’s name is written in italics, it’s probably a species rose, like this Rosa glauca. Source: T.Kiya, Wikimedia Commons
• grow spontaneously in the wild
• single flowers, scented or not
• bloom once a year
• fruits (rose hips) often ornamental
• bear species names (Rosa blanda, Rosa glauca, etc.)
• variable hardiness (1 to 10, depending on the species)
2. OLD GARDEN ROSES or HERITAGE ROSES

Old garden rose ‘Rosa Mundi’. Source: Libby norman, Wikimedia Commons
• generally small to medium-size flowers, often double
• often very fragrant
• most bloom only once a year
• many subcategories: gallica roses, damask roses, moss roses, etc.
• variable hardiness (4-9, depending on cultivar)
3. BUSH ROSES
Repeat-flowering roses, most developed after 1920. They were, through the 20th century, the most popular garden roses, but are now being replaced by the easier-to-grow shrub roses (see below). There are several categories:
A. Hybrid Tea Roses:

Hybrid tea rose ‘Peace’. Source: Arashiyama, Wikimedia Commons
• large, double, reblooming flowers with high-centered buds
• one flower per stem, rarely more
• stiffly upright habit with sparse foliage, making a fairly unattractive plant
• height: usually 3-5 ft (1 to 1.5 m)
• usually grafted
• not very hardy (zone 8); winter protection needed in most climates
B. Grandiflora Roses:

Grandiflora rose ‘Queen_Elizabeth’ Source: Captain-tucker, Wikimedia Commons
• essentially a hybrid tea with 3-5 flowers per stem
• all other characteristics like hybrid tea
• not very hardy (zone 8); winter protection needed in most climates

Floribunda rose ‘Iceberg’. Source: pxhere.co
• smaller flowers, single or double, carried in large sprays (5 and above)
• stiff habit, but smaller, bushier and more attractive than hybrid tea
• height: around 3 feet (90 cm)
• usually grafted
• usually hardier than hybrid teas (usually zone 7, sometimes zone 6)
D. Polyantha Roses:

Polyantha rose ‘The Fairy’. Source: rzysztof Ziarnek, Kenraiz, Wikimedia Commons
• significantly smaller flowers, borne in dense clusters
• abundant bloom most of the gardening season
• attractive habit, often spreading
• height: 30-60 cm
• usually grafted
• often fairly hardy (zones 4, 5 or 6)
E. Miniature Roses:

Miniature rose Mandarin Sunblaze®. Source: http://www.starrosesandplants.com
• small flowers, individual or clustered
• most rebloom
• height: usually between 6 and 24 inches (15-60 cm)
• grown on their own roots (not grafted)
• often fairly hardy (zone 4 or 5)
• can be used as houseplants if given a period of cold dormancy
4. SHRUB ROSES
(includes ground cover roses, landscape roses English roses [David Austin roses], etc.)

Shrub rose ‘Henry Hudson’. Source: eaglelakenurseries.com
• various origins
• usually robust, informal habit creating a shrub effect
• single or repeat blooming
• variable height, usually more than 2 ft (60 cm)
• grown on their on own roots (not grafted)
• often offer good disease resistance
• excellent hardiness: up to zone 2 for some
5. CLIMBING ROSES

Climbing rose ‘Blaze Improved’. Source: http://www.jacksonandperkins.com
• long flexible canes from 8 to 20 feet (2.5 to 6 m) in length
• can be trained and tied to arbors, trellises and pergolas
• all other characteristics are highly variable; flower size, abundance, appearance, rebloom, hardiness, etc.
6. TREE ROSES (ROSE STANDARDS)

Tree roses. Source: Наталия19, Wikimedia Commons
• most are bush roses
• generally very tender (zone 7 or 8)
• often need to be buried in trenches for better winter survival in cold climates
• some are non-grafted, produced by selective pruning of shrub roses, and these are sometimes quite hardy (zone 5 or even 4)
There you go: the basic rose classifications you need to know. Good growing!