February - March 2005 issue: (download
in pdf format)
Know your area’s hardiness
zone when selecting plants
Adaptations can make gardening
easier on the knees for older Iowans
Test soil before adding garden lime
Unglamorous part of rural living
Researching potential pets helps
prevent headaches, heartache
Understand choices when selecting
Protect Iowa’s aging oaks through
disease identification and control
your area’s hardiness zone when selecting plants
By Joy Rouse, Warren County Extension Education
While looking at plants in a garden catalog, you find
one that looks perfect for your garden. The catalog
states it is a Zone 2 plant; you wonder what that means
and whether the plant will grow in Iowa. A plant hardiness
zone map predicts the adaptability of plants to a specific
climatic area. Zones are based on the average annual
minimum temperatures experienced at weather stations
over time. Many plants may survive in zones warmer
or colder than their designated zones, but mere survival
does not necessarily represent satisfactory performance.
The Plant Hardiness Zone Map prepared by the Agricultural
Research Service (USDA) is the most widely used in
the United States. You can find the map and information
about it at the following Web site: www.usna.usda.gov/Hardzone/index.html.
Iowa falls into Zones 4 and 5. Areas in the northern
part of the state (Northwood) and a section in southwest
Iowa have an annual minimum temperature of -25 to -20
degrees F for Zone 4b. Areas more central in Iowa (Des
Moines) have an annual minimum temperature of -20 to
-15 degrees F for Zone 5a. Remember, these are averages;
a winter with more severe temperatures is harder on
plants. When close to a boundary, choose plants hardy
for the colder zone.
Microclimates and heat zones also are considerations
when choosing plants, trees, and shrubs. For more information
about microclimates and heat or hardiness zones, stop
by or call your local
ISU Extension office and ask for RG 215, Gardening
in the Zones.
can make gardening easier on the knees for older
By Mary Ann deVries, Polk County Extension
Gardening is a hobby that sustains many of us physically
and mentally for a lifetime. According to the American
Journal of Public Health, a survey of Medicare claims
for people 65 and older found that those who gardened
had 19 percent lower health care expenses that those
who did not report gardening.
The question as gardeners grow older is how to keep
gardening in spite of the physical limitations associated
with aging. Gene Rothert, past president of the American
Horticulture Therapy Association, believes the secret
to lifetime gardening is adapting the garden to meet
our needs. His number one recommendation: raising the
soil level to where stooping is no longer necessary
to reach it. Typically, this is accomplished through
the use of raised beds or containers.
You can construct permanent raised beds from decay-resistant
wood, concrete block, or brick. The soil height depends
on the ability of the gardener. Beds 2 to 3 feet high
are appropriate for anyone who needs to be seated while
gardening. Three to 4 feet is an appropriate width
for raised beds that can be reached from two sides.
Container gardening is another way to raise soil
levels. Anything that can hold soil and provide good
drainage can serve as a container. This includes clay
pots, wheelbarrows, or even discarded tires. Smaller
containers are especially useful because you can move
them to take advantage of sunny areas or bring them
indoors. Soil in raised beds and containers should
be light and well-drained. A successful soil mix uses
equal parts topsoil, organic matter (e.g. well-rotted
manure), compost, and coarse sand.
Another important consideration for older gardeners
is that access to the garden be smooth and level. Avoid
brick and grass paths because of their unevenness due
to winter heaving. Benches or chairs for resting along
garden paths are also important to the older gardener.
You can see examples of public gardens designed for
individuals with disabilities, often called enabling
gardens, in Waterloo and Altoona. Call the local
ISU Extension office in those counties for more
information. In Black Hawk County (Waterloo), call
(319) 234-6811. In Polk County (Altoona), call (515)
A useful publication, Container Vegetable Gardening,
is available online from ISU Extension at www.extension.iastate.edu/Publications/PM870B.pdf.
soil before adding garden lime
By Mary Ann deVries, Polk County Extension Horticulturist
Lime isn’t a cure-all for garden problems.
Each spring at my local garden center, I’m
astounded to watch the enormous pile of bagged lime
disappear. My question: Who buys this stuff and why?
It’s a mystery to me how lime became a universal
cure-all for lawns and gardens. Perhaps people remember
their Grandma “liming” her garden each
spring. If she lived in Davenport or somewhere else
along the Mississippi River, this would be a good idea.
Soils there tend to be acidic and can benefit from
lime applications. In Iowa, soil tends to be acidic
in the southeastern areas and becomes increasingly
alkaline towards the northwest. In central Iowa, soils
on average are mildly alkaline and don’t need
Simply put, any chemical application
needs to be justified.
pH is a measure of a soil’s acid or alkalinity
level. Above pH7 (the neutral point), soil is alkaline.
Below pH7, it is acidic. Most plants grow best at a
pH of 6-7 or mildly acidic.
Adding lime raises pH, while adding sulfur lowers
it. It’s not possible to know which, if any,
chemical to use without a soil test from a reliable
lab. The small fee for it is easily offset by the money
saved from not purchasing unneeded products.
Extension resource gives great information
An ISU Extension publication, Modifying soils in
Iowa lawns and gardens, has great information on pH.
This publication is out-of-print, but can be viewed
online at www.extension.iastate.edu/Publications/PM1487.pdf.
You also can contact your local ISU Extension office
for a reprint. Better yet, ask for a soil test kit
so you can make informed choices about chemicals this
part of rural living needs care
By Shawn Shouse, ISU Extension Agricultural
Septic systems serve an important function and need
regular maintenance. Understanding how they work will
help you avoid problems and costly repairs.
A conventional septic system has two primary parts:
the tank and the soil absorption field (sometimes called
a leach field). The soil absorption field biologically
treats the wastewater and soaks it into the soil. The
septic tank protects the soil absorption field from
things that would cause it to fail, namely grease and
How septic systems work As wastewater leaves the
house through the sewer line, it enters the septic
tank. Heavier solids settle to the bottom as sludge.
Lighter grease and floating solids rise to the top
as scum. Sludge and scum are trapped in the tank, allowing
cleaner liquid to pass from the tank to the soil absorption
field for treatment and disposal.
Bacteria may decompose some of the scum and sludge,
but the rest needs to be periodically removed. This
occasional maintenance is required for all septic tanks.
There are no additives that eliminate this need. Failure
to remove sludge or scum can cause these materials
to pass into the soil absorption field where they can
plug the system, causing failure and expensive repair.
Caring for a septic system
- Be conservative in your water use. The more water
you use, the more that must go through the absorption
- Be careful what you put down the drain. Toxic
materials can harm bacteria in the septic tank and
pollute ground water. Fats, grease, coffee grounds,
sanitary napkins, disposable diapers, and cat litter
decompose slowly, if at all, and will fill the septic
- Protect the absorption field. Keep cars and heavy
equipment off it. Tree and shrub roots may plug the
- Avoid septic tank additives. Yeasts, enzymes,
bacteria, and chemicals are not necessary, and some
- Clean your septic tank every three to five years.
For more information, including ways to estimate
and measure sludge and scum accumulation, ask your
local ISU Extension office for publication AEN-133,
Maintaining the Home Septic System. Visit the Web sites
listed below for more information.
potential pets helps prevent headaches, heartache
Linda Nelson, Dallas County Extension Education Director
Ever wished you had researched a pet before bringing
it home? Did you choose one not suited to your lifestyle?
Were you aware of the potential diseases it could get?
Because pets require a commitment, they can teach children
about responsibility. That’s why researching
your choices before selecting a pet is important. Doing
so will improve the likelihood that the pet you choose
fits your lifestyle.
Find pet info on the Web
The American Veterinary Medical Association has two
Web sites that can help you make pet decisions. The
first site, www.avma.org/careforanimals,
is a good place for you and your children to find information
The “Animated Journey” link allows kids
to click on individual animals for more information.
Another link, “Paws for Pets,” provides
health tips from a vet to new pet owners. “Kids
Corner” has fun activities to teach children
about responsible pet care.
In-depth information for adults is available at another
You can read about pet health, pet loss, and selecting
Did you realize pets can contract Lyme Disease? Did
you know that 50 percent of all breast tumors in dogs
and 85 percents of all breast tumors in cats are malignant?
More importantly, did you know that spaying a cat between
six and eight months of age will reduce its cancer
Get the information you need to make responsible
choices that will result in happy pets and happy families.
choices when selecting roofing materials
By Shawn Shouse, ISU Extension Agricultural
Several options are available for home roofing materials.
Knowing the pros and cons of each will help you decide
which to use.
Asphalt shingles are the most common roofing material
in the United States. They are made with a core mat
of fiberglass or organic (cellulose) fibers. Multiple
layers of asphalt, topped with a layer of crushed stone,
cover the core mat. The surface grit layer protects
the asphalt and provides multiple color options.
Asphalt shingles are durable, easy to install, and
moderately priced. Their life expectancy is 15 to 30
years. Thickness and weight may offer some indication
of quality, but construction quality and material durability
are not guaranteed.
Laminated asphalt shingles have multiple layers of
asphalt material. They are much heavier and more expensive
than standard three-tab asphalt shingles. They resemble
These shingles are relatively thin and uniform in
size. Wood shakes are split to form thick and irregular
shapes. Wood roofing is relatively expensive to purchase
and install. Its greatest attribute is its rustic appearance.
Its life expectancy is similar to asphalt shingles.
Some building codes prohibit wood roofing because of
fire spread potential.
Metal roofing comes in many different shapes and
materials. Galvanized or painted steel has the lowest
cost and is most common. It is lightweight and has
a life expectancy of 20 to 50 years if properly installed.
Ribbed panels attached with nails or screws are commonly
used in agricultural buildings and can be used with
moderate success on homes. Standing seam metal panels
have no exposed fasteners and are more suitable for
home construction, but are more expensive and difficult
Clay, concrete, and fiber cement tiles offer stately
appearance and excellent life at a premium price.
Slate shingles have a life expectancy of up to 100
years and are the most expensive roofing option. Tile
and slate materials are considerably heavier than other
roofing materials and may require stronger roof framing.
For more details on roofing material options, see “Roofing
Materials Comparison,” Housing and Home Environment
News, Cornell University, www.human.cornell.edu/dea/extension/docs/sum98/roofmat.htm.
Iowa’s aging oaks through disease identification
By Steven D. Lekwa, Story County
Like humans, trees are less able to fend
off disease as they age. Many of Iowa’s oak trees
are more than 100 years old. Aging oaks are susceptible
to several fungus diseases. Oak wilt is the most famous
Initial infection often is from beetles
that feed on sap from infected trees and spread the
fungus spores. Oak wilt can attack healthy-looking
trees and can spread through root grafting underground.
A classic symptom of oak wilt is spreading
patches of dead trees with newly diseased trees around
the edges. Trees suffering stress from compacted or
injured root systems or damage from construction or
storms are at greater risk. Diseased trees show wilted
Red oaks are more susceptible than white
oaks. Oak wilt can attack and kill a red oak in weeks,
but white oaks often battle on for several years as
their crowns weaken and die.
Browning of the leaf starts at the tip
and progresses inward. Sapwood in trees killed by oak
wilt is discolored with fungus that actually plugs
the tree’s vascular system. Symptoms usually
worsen in mid to late summer.
There is no cure for oak wilt. Possible
preventative measures include avoiding injury to a
tree and severing the root connections of adjoining
trees with a vibratory plow once oak wilt is diagnosed.
Removing diseased trees will stop or slow spread of
the disease. Removed trees should be cut up and split
so they dry quickly to prevent continued fungus growth.
They also can be burned.
Another disease, oak anthracnose, is
most common in white oaks. It begins as browning spots
on leaves after a wet, cool spring. The spots grow
to affect more of the leaf as the season progresses
and may cause early leaf drop. A good spring the next
year might show no disease, whereas oak wilt is progressive
once it starts.
Two-lined chestnut borers are insect
pets that attack stressed trees and cause leaf browning
as they tunnel under the bark. Bad infestations can
kill branches. Look for the widening feeding tunnels
under the bark of dead branches.
Oak decline is a disease that affects
all oaks. It’s an increasingly common condition
caused by a variety of stressors, diseases, and pest
factors that can resemble oak wilt. It progresses slowly,
but may be reversible if the conditions stressing the
tree are identified and corrected.
Your Department of Natural Resources
state forester or ISU Extension forestry specialist
can help you diagnosis tree disease and recommend appropriate