Rose (Rosa sp.)

Encyclopedia Article

rose

Rosa

Image of Rosa Carefree Beauty™ (‘BUCbi’)
Rose Carefree Beauty™ (‘BUCbi’)

Family: Rosaceae

Size: 2’ to 6’ tall, depending on variety

Hardiness: zones 4 to 7; although many cultivars (particularly hybrid teas, grandifloras and floribundas) are not winter hardy in Iowa

Leaves: alternate, compound usually with 5 to 9 leaflets.  Each leaflet is glossy with serrate margin

Leaf Color: dark green

Flowers: clustered or single in shades of red, pink, white, and yellow.  Some have fewer petals with showy yellow stamens in the center, others have those stamens turned to extra petals

Fruit: a hip, often ornamental in tones of red or orange and persisting through winter

Habit: open to dense, upright to mounding shrubs, some sucker profusely.

Stem: woody, thorny (technically prickles) round brown stems with a reddish cast

Nativity: hybrid

Insects & Disease Issues: Black spot, powdery mildew, Japanese beetle are serious threats; Aphids, borers, thrips, mites, rose mosaic virus, rose rosette virus, cankers, scale, rusts, borers, leafhoppers and slugs are less severe but still notable

 

Culture and Uses: 

The quintessential garden plant—there are thousands of cultivars and dozens of species with hundreds of hybrids. One of the most popular garden plants, roses are both beautiful and fragrant, but can be a bit labor intensive to maintain, especially those classified as hybrid tea, grandiflora, or floribunda.  Winter hardy and disease resistance "shrub" or "landscape" roses are better options for the gardener and those types are discussed here.  Plant in full sun and well-drained, moist soil. When soil conditions are dry, provide supplemental irrigation, ideally at the base of the plants as wetting the foliage can promote foliar diseases.  Plants grow best in fertile soils and fertilziation during the growing months is beneficial.  Apply a general purpose, balanced fertilizer in early spring, after the first flush of bloom and in mid-July.  Shrub or landscape roses are winter hardy, though some stem die-back may be observed after harsh winters or those with minimal snow cover.  Wait for new growth to break in spring and prune dead branches back to green buds in spring.  Remove spent flowers to promote additional flowering and improve overall plant appearance.  Stop deadheading in mid to late summer if you wish to have the ornamental fruit (hips) on plants through the winter months. Plants are susceptible to a wide range of health issues, because of this cultivar selection is essential.  For best luck select disease-resistant, winter hardy, repeat blooming cultivars like many of those listed below.

The care of hybrid tea, grandiflora, and floribunda roses is considerably more work in Iowa.  Care information for these finiky types of roses can be foud in these links:  General Care; Winter protection (these types of roses will not survive winter in Iowa without protection); When to do Winter ProtectionWhen to do Spring Pruning; How to do Spring Pruning; How to Fertilize; How to Plant and How to Deadhead.

Notable Cultivars & Related Species:

R. rugosa (rugosa rose) - fragrant flowers on spiny plants well suited for difficult areas

R. arkansana (wild prairie rose) - often cited as Iowa’s state flower, single pink flowers with prominent yellow stamens, native to eastern United States. 

Carefree Beauty™ (‘Bucbi) - pink flowers on disease resistant plants—bred by Dr. Buck

Explorer Series - a group of very cold hardy, disease resistant roses bred in Canada

Knock Out® Series - could be the most popular landscape roses on the planet!  Great disease resistance

Easy Elegance® Series - great flower color, disease resistance and cold hardiness

Oso Easy™ Series - disease resistant, better performers in hot stressful conditions

Image of Rosa Knock Out® Series Pink Knock Out (‘RADcon’)
Rose Knock Out® Series Pink Knock Out (‘RADcon’)

image of Rosa rugosa ‘Ames’
Rosa rugosa ‘Ames’

Image of Rosa Easy Elegance® Series Fiesta (‘BAIsta’)
Rose Easy Elegance® Series Fiesta (‘BAIsta’)

Image of a rose infected with black spot
A rose infected with black spot

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