| Beverly Shaw
Question and Answer
Q. Last year, I put in a new lawn. It's doing well,
except, recently, it began leaving a rust-colored powder on my shoes.
Is that something that will affect the health of my turf? -- Jason Burks,
West Lafayette, Ind.
A. The powder is actually millions of microscopic spores
produced by a fungus called rust. There are several different rust fungi
that cause rust. The most common one on Kentucky bluegrass, annual bluegrass,
fescues and ryegrasses is Puccinia graminis. A separate species, Puccinia
zoysia can infect zoysia grass.
Rust becomes a problem when grass plants are growing slowly. When grass
plants are growing fairly rapidly, leaf tissues are removed by mowing
at relatively frequent intervals, and the disease does not become apparent.
With grass plants that are growing slowly, the fungus has sufficient time
(7-14 days) to produce the microscopic spores in infected leaf tissue.
These spores are then wind-blown or splashed by rain or irrigation to
other leaves, where new infections can occur. Consequently, the disease
can become very severe when certain weather conditions occur when the
grass is growing slowly.
Leaf infections occur most frequently when days are dry and windy followed
by heavy dew formation at night. The dry, powdery spores are easily disseminated
by wind currents.
Rust, by itself, rarely kills a grass plant, unless other stress factors
are involved. Rust infected plants are weakened. When the disease continues
into late fall, infected plants may become more susceptible to winter
injury. Young seedlings are highly susceptible, and proper water and fertility
management may be required for early fall seedings.
The rust fungi rarely survive the winter in Indiana. The disease organisms
survive winters in infected tissues in the southern and southwestern states.
Spores of the fungi are wind-borne in spring and summer from those areas
and the disease moves northward into Indiana and surrounding states, usually
in July and August.
Control of rust in the home lawn is best accomplished by fertilizing
and irrigating, as needed, to promote grass growth. Do not promote excessive
growth. Water infrequently, but deeply. Irrigate during the early part
of the day. Irrigate at a time that will permit complete leaf dryness
before dew formation. Watering in the evening will increase the length
of time that free moisture is on the leaves and will increase the chances
of infection. Mow frequently and collect clippings when possible. Several
fungicides will aid in the control of rust, but multiple applications
are generally required, and you might choose to achieve control via management
practices first. You may find products containing chlorothalonil or mancozeb
being sold under various trade names at garden supply stores or nurseries.
Q. My garden is full of pink, blue, yellow and white
flowers. It needs some bolder colors. Everything seems soft and muted.
Which perennials will add a dose of red? -- Lynn Hegewald, Battle Ground,
A. Perennials with red color include Astilbe, Epimedium,
Helleborus, and Bergenia cultivars, and Dicentra 'Bountiful' for areas
with less than full sun. In sunny areas, consider Achillea x''Fanal',
some cultivars of Euphorbia, Hibiscus, Monarda, and Sedum, and a good
number of daylilies and peonies.
Consider adding hot pink and burgundy to the garden, as well. Many "red"
perennials are actually merely in the red family and might be called hot
pink, magenta or burgundy, which may work in your favor. Burgundy looks
terrific with pale pinks but true red can clash. These variants of red
may complement the existing colors in your landscape, while adding a real
punch of vibrant color.
Perennials are wonderful but typically bloom for only part of the growing
season. Adding annuals can give you constant pockets of red or hot pink
from May to October. So can colored foliage. Burgundy foliage, found in
Heuchera cultivars, Japanese maples and more, can give depth and contrast
to nearby pale colors.