There are many factors that come
into play when spinning the roulette wheel of rose diseases in your garden.
Some years you may not have much of a problem with blackspot, rust and mildew
and the next you struggle all season to rid you garden of these nuisances.
Let’s briefly examine our plan of attack.
– Appropriately named for the dark-colored spots that appear on leaves. As the
disease progresses the leaves turn yellow and fall off the plant. Blackspot
often appears in humid areas or later in the summer in area known for July and
August thunder showers.
Leaves exhibiting evidence of blackspot should be
removed (remember to clean up any leaves that fall around the base of the
plant). You may need to cut back areas of the plant.
– Powdery mildew appears as a whitish powder on the leaves and stems of the
plant. Left untreated it will spread along the canes. Powdery mildew is common
to areas with warm summer days but cool and damp nights.
Mildew can be treated with a fungicide spray.
Thin out congested areas of the plant to increase air circulation. Clean around
the base of the affected plants as well.
– Another aptly named disease, rust shows up as orange spots on the underside of
leaves. Rust can spread throughout a plant, defoliating the leaves and possibly
killing the rose.
Although rust can be treated by some sprays, not
all will be effective. Remove effected leaves and areas of the plant. Thin
canes as well to promote better air circulation within the plant. Rust appears
on plants in humid or damp areas so if you are watering with sprinklers you may
want to check into other method that doesn’t leave the upper part of the bush
You may have noticed a pattern to help prevent many diseases common to roses.
Poor air circulation mixed with damp foliage affects both the onset and spread
of disease. If you are constantly fighting disease in your rose garden look at
the spacing between the plants and see if there is any way to increase the air
circulation in the area. Sometimes fences or think plants bordering the garden
can be opened up to promote more air movement.
Although you can’t do much about a damp climate
you can check to see if you are watering the leaves instead of the roots.
Although roses like water they need soaking at the base not in the areas prone
Natural Disease Resistance
Many roses are more susceptible to certain types of disease. The good news is
that there area also many new roses which are naturally disease resistant.
Weeks Roses has several varieties that are not only beautiful, heavenly scented
bloomers but they are also easy to care for because of their inherent ability to
fight off these rose maladies.
Recent All-America Rose Selections (AARS) winners
Julia Child, Strike it Rich, Memorial Day, Livin' Easy, Hot Cocoa and About Face,
are all examples of stunningly beautiful roses with a natural resistance to
disease. (taken from Weeks Roses website)
of the best products to treat rose
disease are Bayer's Rose Disease Control spray. Bayer's All-in-One - controls
insect, disease and fertilizes too. Serenade is a natural organic spray for