Your roses have been
planted, nurtured and have exploded into full bloom. Now
what? Most reference books cover planting, pruning, and
even pest control, quite thoroughly. These are certainly
the most frequently asked questions about rose care. But
what about midsummer maintenance? It's a topic commonly
overlooked but very important for continuous bloom and
plant vigor. Here are a few tips for keeping the bloom
explosion going all summer.
Click on the photo below to find your zone
Deadheading
Fertilizing
PH Levels
Watering
Pests
& Diseases
Deadheading:
Most modern roses, even some
heirloom varieties, will bloom all summer if properly
groomed. "Deadheading" refers to the process of
removing old or spend flowers from the bush. Whether
you've been cutting the flowers to enjoy indoors or have
left them on the bush to beautify the garden, proper
trimming ensures strong reblooming. By deadheading roses
instead of allowing them to form seed hips, you're
signalling the plant to produce more flowers. It's also a
way to continually prune and shape the plant.
Rose leaves develop in sets of three, five, even seven or
nine leaflets. Notice the five leaflet leaves; these are
where you'll want to prune. Cut 1/4" above a
five-leaflet leaf, leaving at least two sets of leaflets
on the stem from which you're cutting. Pick a leaf that
faces outward to cut above and make the cut at an angle
sloping downward toward the center of the bush. Also, be
sure to cut stems back to wood strong enough to support a
new rose — at least pencil-thick is a good guide. If
stems are too small they will either "go blind"
(won't produce a bloom) or will be unable to support the
bloom's weight.
Fertilizing:
While
most rose gardeners fertilize in the spring when growth
begins, midsummer feeding sometimes gets overlooked. Roses
are heavy feeders — it takes a lot of energy to produce
all those large, magnificent blooms! Many different
fertilizers do the job — you can choose from granular,
liquid, organic or slow-release. While each formula has
its advantages, keep in mind that roses prefer a fairly
balanced fertilizer where the N-P-K (nitrogen, phosphorus,
potassium) ratios are fairly even (i.e. 15-15-15 or
5-10-5). High-nitrogen fertilizers without enough
phosphorus and potassium, such as lawn fertilizers, will
produce lush green foliage while sacrificing blooms.
You can combine deadheading and fertilizing, since they
should both be done about every 4-6 weeks. Hybrid tea and
floribunda roses produce new blooms 5-6 weeks after
deadheading, while miniatures and shrubs will recycle in
about 4-5 weeks.
pH:
pH measures the acidity (or alkalinity) of your soil. It's
an important consideration because of its affect on
fertilizer. If soil is overly acidic or alkaline, then
nutrients might be "tied up" in the soil and
won't be available to the plant, no matter how much
fertilizer you apply. Roses prefer slightly acidic soils
(pH of 6.5-7.0). Since some fertilizers can acidify the
soil and since some areas have alkaline water, it's a good
idea to check your soil pH and adjust accordingly by
adding garden lime (dolomitic lime works well) if too
acid, aluminum sulfate or acidifying fertilizer if too
alkaline. Adding more organic matter (compost, peat moss,
decomposed bark, etc.) to the soil also helps to stabilize
the effects of low or high pH.
Watering:
Roses
like a good, deep soak to promote deep rooting and they
will actually develop drought tolerance if established
this way. Frequent light waterings promote shallow roots
that will depend on frequent watering. Applying the water
slowly with soaker hoses or drip irrigation allows the
water to soak in rather than running off, keeps water off
the foliage (wet leaves spread fungal diseases), and
reduces the puddling which can cause clay soils to form a
hard surface less permeable to water. Mulching helps by
reducing evaporation, retaining moisture, and preventing
the soil surface from caking. If you use overhead
watering, do it in the morning so that the foliage will
have plenty of time to dry off before nighttime. Roots
need air as well as water, so don't keep the soil
continually soaked. Allow the top inch to dry off before
watering again.
Pests
and Diseases:
Early
detection and prevention keep these problems under
control. While good things come in threes, so do bad.
Since aphids are mainly a spring pest, the "Big
Three" summer pests are thrips, spider mites, and in
the eastern and southern United States, Japanese Beetles.
Thrips mainly attack rose blooms, especially whites
and yellows, and mites attack foliage, turning leaves a
mottled brown and leaving their tell-tale fine webbing. If
detected early, these pests can be controlled with one or
two sprays of an organic or chemical remedy. An initial
control for both mites and aphids is a wash with a jet of
water from the garden hose. Depending on the severity and
timing, Japanese beetles can be picked off, sprayed or
trapped. If trapping, place traps away from your roses so
they won't be attracted to them.
The "Big Three" of rose diseases are blackspot,
powdery mildew and rust, all of which are
types of fungus. Blackspot occurs during humid or rainy
weather or where watering (especially overhead) is
excessive. Powdery mildew prefers warm days and cool
nights, crowded plantings or damp, shady areas. Rust
develops on moist foliage, so areas with heavy dew or fog
are prone to this disease. Proper rose culture, including
plenty of sun, sufficient air circulation, proper watering
and sanitation (disposing of old leaves and other debris)
will minimize all three disease problems, but they may
still occur. If detected early and treated with a
fungicide (organic or chemical), none of these will spread
out of control.
Whatever spray you use for pest or disease control, always
be sure to follow the directions on the label! This
applies to organics as well as chemical sprays. Even
organics can be toxic if used incorrectly.
It's time to stop and smell the roses. With proper summer
care, roses will be there for you to smell all season. And
what a wonderful reward for the effort — a garden full
of lush color, a welcome retreat from the "dog
days" of summer.
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