SUMMER ROSE CARE
With the arrival of warm summer temperatures, interest in
rose gardening often wanes because the flowers are small, of
poor quality and the colors are faded. Proper care at this time
will insure attractive foliage and an abundance of flowers throughout
next fall and early winter.
Roses are heavy users of nutrients and require regular applications
of fertilizer for optimum growth. With new growth in the spring,
apply fertilizer at the rate of 2 pounds of 19-5-9 slow-release
per 100 square feet of bed area. The soil should be moist before
applying fertilizer. Spread the fertilizer over the surface
of the bed and work it into the surface of the mulch with light
cultivation. Water the bed thoroughly after applying fertilizer.
Repeat the fertilizer applications every 6 to 8 weeks.
For optimum growth and flower production, avoid moisture deficiency
or over watering. Frequency of watering depends upon the soil
type, climatic conditions, the growth stage and development.
During periods of drought and high temperature, watering may
be needed every 3 to 4 days.
Roses may be irrigated by flood or sprinkler irrigation. If
the sprinkler system is used, schedule watering early in the
morning to allow the foliage go dry before exposure to the hot
sun. This method also helps prevent fungal diseases caused by
the foliage remaining wet during the night.
Another important cultural practice with roses is mulching.
Using a 2-inch layer of mulching material, such as shredded
pine bark, is an excellent cultural practice. It conserves moisture,
keeps soil insulated against heat and reduces weed growth.
Undoubtedly the most common topic discussed and cussed about
roses is insect and disease control. Here are a few guidelines
from the experts.
Black spot is the biggest disease problem of roses. This fungal
disease appears on the leaves as circular black spots with fringed
edges. The leaves may turn yellow and drop prematurely. Prevent
this disease by 1) eliminating excess water on the foliage when
irrigating and 2) by regular spraying of an approved fungicide.
According to several professional rose growers, Funginex or
bayleton (FungAway) are the best fungicides for black spot.
Another rose disease that occurs every year is powdery mildew.
This disease appears on young leaves, shoots and buds as a white
powdery mass of fungal spores. Powdery mildew is worse when
the days are warm and the nights cool. Control immediately after
identifying the disease in the spring. Again, most rose growers
recommend Funginex or bayleton (FungAway) for effective control.
The two major insects on roses are aphids and thrips. The aphids
are tiny insects that cluster on young shoots and flower buds.
They have soft bodies and are green, brown or red. Aphids suck
the juices of the plant and give it an unthrifty appearance.
Several insecticides will control aphids, such as diazinon,
Malathion and Orthene. The product Orthene is the most widely
used by most rose growers because it is systemic (goes into
the plant and provides longer protection).
Thrips are sucking insects that are very tiny, cigar-shaped
and cream-colored. The evidence of a thrip infestation is deformed
flowers, especially on white varieties. If damage is severe,
flower buds may not even open. Break open the deformed flowers
and you should find hundreds of tiny thrips having a field day.
Orthene insecticide is again the recommendation of most rose
A weekly pesticide spray schedule is essential to control
these and other pests in order to produce top quality roses.
In consulting some of the best rosarians in San Antonio, they
offered this advise. Fertilize your roses monthly and spray
thoroughly every ten to twelve days throughout the growing season
with a combination spray of Funginex and Orthene.
As always, read the labels of all pesticides you use. Follow
the directions to the letter and keep the chemicals away from
For more information about growing roses in Texas, see: