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University
of Rhode Island GreenShare Factsheets
Cultural
Requirements of Roses
Roses
are among the most popular garden flowers grown in America, with
new varieties produced yearly. Many roses require constant and almost
meticulous care in order to produce healthy plants and beautiful
flowers. However, in recent years disease resistance and ease of
maintenance have become sought after traits. Many new roses, especially
shrub roses, are easy to grow and are widely available through garden
centers and plant catalogues. Roses
will grow in a variety of soils, but it is important that the soil
be well drained--if drainage is inadequate, install a 3 inch agricultural
drain tile. Soil pH should average between 5.5 and 6.5. A soil
test will determine the actual pH of the soil and whether lime
or sulfur will be needed to correct its acidity. Air
circulation and full sunshine are important for growing healthy
plants. Roses should be planted where air circulation is not hampered
by screens, walls, fences, buildings, hedges or other plantings,
and should receive a minimum of 6 hours of direct sunlight each
day. If possible, it is better for the plants to receive sunlight
in the morning--bright afternoon sun will eventually affect the
color of the flowers. Roses
are heavy feeders, especially when in flower. They will not require
additional fertilizer the first year if they have been properly
planted in the spring. Roses planted previously will require two
or three applications of a complete fertilizer during their growing
season. Two to three tablespoons of 5-10-5 fertilizer per plant
are applied in early spring after the winter protection has been
removed and the plant is pruned to remove damaged wood. The second
application should be made in June, when the plant is in flower.
If weather permits, a third application may be made before the middle
of August. Fertilizer
should be applied when the soil is moist. Work gently into the soil
and water amply. Caution should be taken not to let fertilizer come
in contact with foliage or canes. Thorough,
infrequent watering is preferable to light, frequent watering in
rose culture. Roses should be watered only when needed, with enough
water to penetrate the soil to the depth of the root system--about
one foot. Watering from overhead is not recommended, as it tends
to encourage the growth of fungus. Place the garden hose or soaker
in the bed and allow the water to run slowly.
The application of a mulch in the summer helps to conserve moisture
and keep the roots cool. Pine needles, buckwheat hulIs, ground corn
cobs and peat moss are all excellent mulches. Pine needles and ground
corn cobs are loose and allow for better air circulation. Buckwheat
hulls and peat moss should be worked into the upper two or three
inches of soil. Buckwheat hulls are very light and may be blown
away by even light winds. Peat moss should be kept damp--once dry
it is difficult to re-moisten. Mulches
should be applied when the soil is damp and placed to a depth of
about one to two inches. (Note that the soil should be tested every
year or so, as mulches may alter the soil pH.) Additional nitrogen
may also be needed to replace that used by the mulch in the decomposition
process.
Pruning needs vary with the kind of rose. Pruning is done to remove
old, weak and diseased wood and conflicting canes, and to maintain
the proper size and shape of the plant. • Remove
the flowers as soon as they begin to fade during the first
year
after planting. • Remove dead
canes at the base of the plant and remove diseased or damaged
wood to a point just below the damaged area and above a
growth bud. • Pruning is
usually done in the early spring, after the winter protection
has been removed or when the buds begin to swell. • Prune canes
back to an outside-facing bud in order to avoid crowding of
branches in the center of the plant and to create an open center
for the best Iight and air movement. Caution should be taken
to
leave at least three buds on each cane to insure good growth. Many
roses, especially hybrid teas, have been grafted or budded on understock
of a different species. It is important that any growth below the
graft or budding points be removed. Although the understock is often
more vigorous in growth, it produces inferior flowers. If the plant
has more than five good canes from the base, thin them by removing
the weakest ones. When
pruning a rose, make a slanting cut no more than 1/4 inch above
a growth bud. Make certain that the pruning shears are clean and
sharp. Dull clippers cause jagged cuts favorable to fungus growth.
Unclean shears may spread disease. Climbing
Roses - During spring flowering, remove the oldest canes. Immediately
after flowering, cut laterals back to a length of 6 to 12 inches.
Climbing
Hybrid Teas - Little pruning required, except for thin, weak
shoots. Do not prune severely before the plant is established or
it may lose its climbing habit. After 2 years, some of the oldest
wood may be removed. Floribundas
- Prune in the spring after the buds begin to swell, otherwise average
pruning. Prune back to the second bud below the flower head. Grandifloras
- Prune as for floribundas. Remove 2-year old canes, leaving 3 to
4 buds from the base of the plant. Hybrid
Perpetuals - Prune as for fIoribundas. In early spring, remove
all dead, weak or injured growth and then thin to leave 4 to 8 vigorous,
well spaced shoots. These may be cut back to 2-3 feet from the ground.
Hybrid
Teas - Moderate to light pruning recommended. Polyanthus
- Little pruning required. In the spring remove old canes and those
which failed to bloom the previous year. Ramblers
- Prune immediately after flowering to remove old and recently flowered
wood. Prune vigorously. Leave new shoots unpruned except for dead
and diseased wood. Shrub
- Prune to remove dead and diseased wood. Cutting
Roses For Indoor Use:
Roses should be cut in the early morning. Make the cut 1/4 inch
above an outward pointing leaf bud, making sure to leave at least
3 leaf buds on the cane. Adapted
from Clifford W. Collier, Jr and John Jett, West Virginia University
Extension, 2000
Pesticides
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
For more
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
University
of Rhode Island Cooperative Extension provides equal program
opportunities.
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