Article on roses
ROSE ‘Queen of Flowers’
Rose is a woody perennial of the genus Rosa, within the family Rosaceae. There are over 100
species. They form a group of plants that can be erect shrubs, climbing or
trailing with stems that are often armed with sharp prickles. Flowers vary in size and shape and are usually large and
showy, in colours ranging from white through yellows and reds. Most species are
native to Asia, with smaller numbers native to Europe, North America, and
northwest Africa. Species, cultivars and hybrids are all widely grown for their beauty and often are fragrant.
Rose plants range in size from compact, miniature roses, to climbers that can
reach 7 meters in height. Different species hybridize easily, and this has been
used in the development of the wide range of garden
roses.
Roses are best known as
ornamental plants grown for their flowers in the garden and sometimes indoors.
They have been also used for commercial perfumery and commercial cut flower
crops. Some are used as landscape plants, for hedging and for other utilitarian
purposes such as game cover and slope stabilization. They also have minor
medicinal uses. Roses are a popular crop for both domestic and commercial cut flowers. Generally they are
harvested and cut when in bud, and held in refrigerated conditions until ready
for display at their point of sale.
Roses may be planted throughout the summer
from nursery containers. However, the current season’s stock is to be preferred
rather than container stock held over from the previous year. With the
exception of miniatures and smaller cultivars, roses generally do not perform
well when maintained in nursery pots for more than one season.
Planting sites may have full sun to
partial shade; however, roses do best with 6 hours or more of direct sun.
Roses need to be irrigated in most locations. Drought stress
leads to defoliation and sunburn of canes, and may contribute to spider mite
problems. However, overwatering or poorly drained soils may lead to root
disease and nutritional deficiencies. Frequency and duration of irrigation
depend on weather conditions and soil
texture. Roses do best when 50% of available water is depleted between
irrigations.
Roses prefer well-drained soil with a pH near the neutral
value of 7.0. so electrical conductivity
(EC) values, which measure the level of salt
ions in the soil, should be less than 2.0 dS/m.
Pruning provides an opportunity to direct growth and
invigorate rose plants. A starting point in pruning is to remove
diseased and damaged wood Between one-third and two-thirds of healthy wood may
be removed through a combination of heading and thinning cuts, which should be within 1/4
inch above outwardly growing lateral buds or branches.
Weeds are common in many landscape situations including
around rose plantings. In extensive plantings or professionally managed public
or commercial landscapes, mulches and hand-weeding may be supplemented with
herbicides. The preemergent herbicides oryzalin (Surflan) and pendimethalin
(Pendulum) can be used around roses before weeds emerge or after weeds are
removed, but before others germinate. While these herbicides control primarily
grasses, they also control broadleaf plants such as chickweed, fiddleneck,
knotweed, lambsquarters, pigweed, prostrate spurge, oxalis (from seed), and
purslane. These herbicides will not control established weeds. To control
established grasses, the postemergent herbicides fluazifop-p-butyl (Fusilade),
sethoxydim (Sethoxydim), and clethodim (Envoy) may be used when the grass
plants are small.
Roses
are harvested at different levels of maturity, depending on marketing and
cultivar. For long-distance transport or storage, roses should usually be
harvested with some of the sepals reflexed. Flowers harvested before the sepals
reflex may fail to open, or may be more susceptible to bent neck.
Objective
grading is based on stem length; subjective grading is based on flower
maturity, stem straightness, stem caliper, and quality of flower and foliage.
The number of stems per bunch, and bunch pattern (single layer, staggered
two-layer) depends on market preferences.
Roses
should be stored, dry, at 0-1ºC. Roses intended for long-term storage should be
packed in polyethylene-lined cartons and pre-cooled. They may be held for up to
2 weeks in dry storage if the temperature is maintained steady and close to the
freezing point.
A variety of plant pathogens may attack outdoor roses from
time to time. Although powdery mildew(Sphaerotheca pannosa) is perhaps
the most common disease problem, a number of other diseases, including rust(Phragmidium
disciflorum), black spot(Diplocarpon rosae), botrytis, downy mildew( Peronospora sparsa), and
anthracnose(Sphaceloma rosarum), may affect roses where appropriate
conditions prevail.
Besides this some nutritional defficiencies and physiological
disorders may also occur.
REFERENCES
Flint, M. L., and J. F.
Karlik. 2000. Healthy Roses. Oakland: Univ. Calif. Agric. Nat. Res.
Publ. 21589.
Karlik, J. F. 1998. Weed management
for roses in landscape plantings. Proc. 50th Annual Calif. Weed Sci. Soc., pp.
12-14.
Karlik, J., and C. Harwood. 1991.
Landscape roses bred for performance. Calif. Landscape Mag. 16(3):28–29.
Karlik, J. F., and S. A. Tjosvold.
2003. Integrated Pest Management (IPM) for Roses. In Encyclopedia of Rose Science, A.V. Roberts ed. Amsterdam,
Netherlands: Elsevier Science.
Dreistadt, S. H. 1994.
Pests of Landscape Trees and Shrubs. Oakland: University of California DANR
Publication 3359.
Dreistadt, S. H. 2001.
Integrated Pest Management for Floriculture and Nurseries: Oakland: University
of California DANR Publication 3402.
Flint, M. L., and J. F.
Karlik. 2000. Healthy Roses: Environmentally Friendly Ways to Manage Pests and
Disorders in Your Garden and Landscape. Oakland: University of California ANR
Publication 21589.
Mohammad Adnan (Author)
About Guest Author:
Mohammad Adnan, student of Agriculture in University of Agriculture Faisalabad and he is a guest author for Agriculture Information Bank
Supporting Heavy Plants
nteresting rather than showy but yet more interest for the winter garden.
Robert Vernon | 07:00 UK time, Monday, 19 December 2011
