30 inches. Leave more than six canes on bushy floribundas,
and leave them at a height of 24 to 30 inches, depending on
their mature size, location and purpose in the landscape.
For a video demonstration on pruning hybrid tea roses, go
to
http://msucares.com/gardenvideos/index.html#
and
choose “Pruning Hybrid-T Roses” under the spring list.
Modern shrub roses and English roses should be cleaned as de-
scribed above. Reduce their overall size by approximately
1
⁄
3
.
Retain the natural shape of the shrub unless the plant is being
trained to a trellis or fence. In general, old garden roses should
not be pruned much. Clean out dead or diseased wood, but
maintain their natural form.
Trim roses that bloom only in spring after the flowering has
ended because they produce their flowers on wood of last sea-
son's growth. In general, pruning spring-bloomers and climb-
ing roses usually involves cleaning the plants of dead or
diseased growth and shaping the plants to their natural or de-
sired growth pattern. Some climbing roses can be rejuvenated
every year by cutting out one or two of the oldest canes that
no longer bloom well. Roses that are trained to grow vertically
may tend to bloom only at the top of the main stems. Reduc-
ing the top of the main stem slightly and encouraging growth
of horizontal side stems will promote better bloom through-
out the column of the plant.
How should I cut blooms?
Many gardeners grow roses to cut flowers for home and
friends. The long, single stem blooms of hybrid tea roses are
perfect for cut flowers. Use hand pruners that cut like scissors
to make the cut at a 5-leaflet leaf (see illustration). Cuts in this
area ensure strong vegetative breaks and encourage a bushy
plant. Rose exhibitors often want to produce the biggest, bold-
est, best bloom they can for flower shows. They achieve this
by disbudding a stem. Disbudding is the process of removing
all side buds except the terminal bud at the tip of the stem
when the buds are small. All the growing energy is therefore
concentrated into the terminal flower.
What is deadheading and why is it important?
Most roses respond well to the removal of blooms that are
past their prime. Some of this occurs as you cut flowers for
arrangements. Flowers that do not get cut for those purposes
should also be trimmed off the shrub to encourage new veg-
etative growth that will bloom again. Cut off less foliage if the
plant is young or under stress. Cut farther down the stem if
the plant is actively growing and the canes become top-heavy.
Lightly reshaping the shrub about midway through the grow-
ing season is often referred to as summer pruning. Stop prun-
ing in early fall so that the shrub does not go into winter with
tender new growth. Deadheading and summer pruning are
good times to groom the shrub and remove unsightly dead
blooms, diseased foliage and fallen leaves.
Roses that bloom in sprays also benefit from deadheading.
Wait until the entire spray is mostly finished and then remove
the whole group of spent flowers at one time.
Not all roses need this much attention. There are many culti-
vars whose blooms are simple and self-cleaning. These culti-
vars make good landscape shrubs, although they may not be
the best choice for exhibition flowers. They make up for the
lack of fancy flowers by producing masses of flower color all
season long.
Can I propagate my roses?
It is best to buy named, healthy, vigorous 2-year-old plants
from a reliable nursery where propagation and production
conditions are well controlled. Propagation of patented plants
is not legal unless the breeder gives permission. Many of these
roses are grafted onto rootstocks because they are not strong
enough to grow on their own roots, or they require a long es-
tablishment time if grown without grafting. A common root-
stock used on grafted roses throughout the United States is
‘Dr. Huey’. ‘Dr. Huey’ is a red-blooming rose with long, arch-
ing canes. This growth habit and bloom color appear when
the scion (the top part of a grafted rose) dies or is overgrown
by the rootstock. R. x fortuniana rootstock can be found on
First five-leaflet
leaf above break
First five-leaflet
leaf below flower
Bud break of last cut
petals
sepals
FLOWER BUD
23
grafted roses where rose exhibitors and gardeners seek more
robust growth. This rootstock is not quite as cold-hardy as ‘Dr.
Huey’ but is an exceptional rootstock in the deep South. It
grows naturally as a large climber with small white blooms.
Old garden roses and non-patented roses are legal to propa-
gate, and many can be grown on their own roots. That is how
some old family roses get passed down through generations,
losing their identity but still making good memories. Roses
can be shared in this manner by rooting hardwood or soft-
wood cuttings or potting up root suckers. Some roses are eas-
ier to root than others.
Insect and Disease Pests of Roses
There are many diseases, insects and mites that attack and
damage roses. Some of these are minor pests, while others can
cause serious damage if not detected and treated early. Al-
though rose growers can use many non-pesticide methods to
reduce the potential for pest outbreaks, sometimes pesticide
applications are required to protect roses from diseases, in-
sects, or mites. Check your rose plants regularly so you can
detect and treat problems before they cause serious damage.
When multiple pests require treatment, it is often practical to
combine recommended insecticides, miticides, or fungicides
into one spray, but read the labels of all involved products
carefully before tank mixing. When spraying your roses, keep
in mind that pesticides do not work unless they reach the tar-
get pest, so take care to spray thoroughly. Directing sprays to
the undersides of leaves is especially important when at-
tempting to control spider mites, diseases, and certain other
pests.
caution:
Mix only the amount you will need for one applica-
tion. Do not store pesticides after they are mixed with water.
For safe and effective pesticide use, always read and follow
label directions.
Insects
Some of the more common or important rose pests are briefly
discussed in the following paragraphs. See extension publi-
cation 2472, insect pests of roses
, for more
specific information on the insect and mite
pests of roses and how to manage and con-
trol these pests.
thrips:
Thrips are tiny, spindle-shaped in-
sects that damage blooms by feeding on the
petals of developing buds, causing petals to be distorted and
discolored. Light-colored blooms are generally more suscep-
tible, but thrips will injure dark-colored blooms as well, espe-
cially when numbers are high. Infestations are heaviest in
spring and early summer, when adult thrips are migrating
from maturing spring weeds, clovers, and winter grain crops.
chilli thrips:
Rose growers need to be alert for this non-na-
tive species of thrips that threatens to become established in
the state. Unlike other thrips, chilli thrips feed primarily on
foliage, causing leaves to be distorted and discolored, but they
will also damage blooms. Damage by chilli thrips is some-
times mistaken for herbicide injury. Use a hand lens to check
the undersides of symptomatic leaves for the presence of
thrips. Heavy infestations can cause severe damage and can
even result in complete defoliation.
Aphids
: These small, soft-bodied in-
sects cause damage by sucking the
sap from leaves, flower buds, and
tender stems. Heavy infestations
cause distorted and stunted growth.
Aphids also produce large amounts
of honeydew, which causes plants to
be sticky and supports the growth of
sooty mold fungi, which produces an
unsightly black growth on the leaves
of affected plants.
rose Scale:
Rose scale and other ar-
mored scale are immobile, somewhat
oyster-shaped insects that damage
roses by feeding on the canes with
their long, thread-like mouthparts.
Rose scale do not produce honey-
dew, and infestations are easy to
overlook because they adhere closely
to the stem and are often mistaken
for bark or debris. Heavy infesta-
tions cause plants to be unthrifty and
can even cause death of whole canes.
Spider Mites:
These tiny arthropods are
some of the most common and most dam-
aging pests of roses. They feed on the un-
dersides of leaves, sucking sap from
individual plant cells. Damage initially ap-
pears as a light-colored stippling of the
leaves, usually beginning along the mid-
vein. Use a hand lens to check the under-
Thrips
enlarged 21 times
Spider Mite
enlarged 20 times
Rose Scale
24
Aphids feeding
on rosebuds