The Good Earth
Dubuque County Master Gardener’s
Publisher Mary Ann Emery
Extension Master Gardener
Volume No. 10
Issue No. 3
Date March, 2011
Dubuque County Extension
14858 West Ridge Lane, Suite 2
Dubuque, IA 52003-8466
563-583-6496; Fax 563-583-4844
www.extension.iastate.edu/dubuque
Items of Interest!
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Hello everyone!!!
It certainly has been busy around my house since the
last newsletter. My neighbor, who owns a cabinet
shop, suggested that I needed a new kitchen (mine
was only 35 years old). So I had the opportunity to
help build and finish the cabinets at his shop. We got
them all finished and delivered and then installed.
When you are not used to living out of rubbermaids
and having stuff (and I mean LOTS of stuff
everywhere) I had what I thought were going to be
several melt down days. But it is completely behind
me and now I am ready to get out in the yard and start
doing Spring cleaning. Working in the yard has to be a
piece of cake compared to redoing an entire kitchen - right? I certainly hope so.
Message from Marv
Spring Seminar
Ask The Experts
Chicago Flower Show
Linn County MG Lectures
All-Iowa Hort Expo
Mondays in March
Green Scene Garden Symposium
Pruning Raspberries
Plant & Insect Diagnostic Clinic
Row Cover Crops
Master Gardener News Items
Please mark your calendars with these important dates.
Thanks Everyone!
Master Gardener Advisory Committee Meeting; 2 nd
Monday of each month, 6:00 pm at the Extension
Office. These meetings are open to all Master
Gardener’s, Trainees (interns) and invited guests.
Please come and support your Extension programs.
M.G. Advisory Committee Meeting: Monday,March
14, 2011 at 6:00 pm at the Dubuque County
Extension Office.
b) Spring Seminar, Saturday March 5, 2011 7:30 a.m.
to 2:30 p.m. NICC Town Clock Center.
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I am really looking forward to the Spring Seminar
which will be here before we know it. There will be
plenty of wonderful speakers and it should be a
wonderful day. Hope to see you there!!!
-- Mary Ann Emery
Mission Statement
The mission of the Master Gardener Program is to
provide current, research-based, home horticulture
information and education to the citizens of Iowa through
ISU Extension programs and projects. Through their
participation in educational activities, Master Gardeners also
increase their own personal knowledge in horticulture.
Master Gardeners extend Iowa State University Extension’s
consumer horticulture education programs through volunteer
activity.
NOTE: These events have been approved for volunteer
hours toward gaining or maintaining your Master
Gardener certification. Please contact Marv Stoffel at
(563)582-4764 or by email at stoffel19@mchsi.net if you
want to be a volunteer at any of these events. Watch this
area for more exciting events to come.
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From Marv Stoffel, President
Ask the ISU Extension
Gardening Experts
Master Gardener Advisory Committee
This is a great time of year to just sit down and think
about the time we spend in our yards and gardens. The
weather is beginning to cooperate with warmer
temperatures. But, don't forget that March can also be a big
snow month. Spring officially starts on March 20th. I'm sure
most of you are getting a little anxious about getting outside.
Our Call Center starts on Mondays in March. Thanks to
many of you that have already signed up to volunteer. There
are still a lot of openings to fill. We would like all of you to
help out with this. It's a great opportunity to get your
volunteer hours in and have fun doing it at the same time.
The Spring Seminar is coming up fast. It will be on
Saturday March 5th. Our team of volunteers for this event,
chaired by Cathy Darrah, have done a fantastic job of
planning, getting good speakers, food, information, etc. If
you still want to volunteer with food or your time please call
Cathy. The Spring Seminar should be a huge success. We
hope to see you there!!!
Why is it necessary to prune grapevines?
Grapevines produce fruit clusters on the previous
season’s growth. Before pruning, a grapevine may have 200
to 300 buds capable of producing fruit. If the vine is not
pruned, the number of grape clusters would be excessive
and the grapevine would be unable to ripen the large crop or
produce adequate vegetative growth.
The purpose of pruning is to obtain maximum yields of
high-quality grapes and to allow adequate vegetative growth
for the following season.
Spring Seminar
The Spring Seminar scheduled for Saturday,
March 5, 2011, at the NICC downtown campus will be
here before we know it. If you have anything that you
can donate for door prizes all items are always greatly
appreciated. Everyone likes having their number
drawn for a prize so please keep the seminar in mind
when you are out shopping for something to donate.
We also will accept any extra seed catalogs as well
for that day.
Everyone is asked to please bring either something
for breakfast or a dessert to go with lunch. Please call
Cathy Darrah at 563-588-0743 to let her know what
you will be bringing to share at the Seminar.
We will be having some new speakers this year but
we will also be having Sara Carpenter back again. It
should be a very informative day so please plan on
attending. You need to get your reservations in to
Trish by March 1st. And please be sure to indicate
your choice for the lunch that will be provided. Thanks
and hope to see all of you there.
If you are looking for volunteer hours, help will be
needed on Friday the 4th at 4:30 to help set up. We
will need help setting up tables, stuffing folders and
there will be other miscellaneous tasks that need to be
completed. So if you can help just please be at the
downtown center. Thanks in advance.
When is the best time to prune
grapevines?
The most desirable time to prune grapevines is late
winter or early spring. In Iowa, pruning can begin in late
February and should be completed by early April.
Grapevines pruned at this time of year may “bleed” heavily.
However, the loss of sap does not harm the vines.
What type of pruning equipment is
needed to prune grapevines?
Tools required to prune grapevines include hand shears,
lopping shears and saw. Brightly colored ribbons or cloth
strips can be used to identify fruiting canes and renewal
spurs.
What is the proper way to prune
grapevines?
To maximize crop yields, grapevines are trained to a
specific system. The most common training system used by
home gardeners is the four-cane Kniffin system. The fourcane Kniffin system is popular because of its simplicity. In a
four-cane Kniffin system, the canes of the grapevine grow
on two wires, one located 3 feet above the ground and the
second 6 feet high.
When utilizing the four-cane Kniffin system, select four
canes on the upper wire, two going in each direction. Also,
select four canes on the lower wire. To aid identification,
some gardeners tie brightly colored ribbons or strips of cloth
on those canes they wish to retain. All remaining one-yearold canes should be completely removed.
Going back to the upper wire, select two of the remaining
four canes (one going in each direction). Prune these canes
back to one or two buds. These short one or two bud canes
are referred to as renewal spurs. The renewal spurs provide
the shoots or canes that produce next year’s crop. Prune the
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remaining two canes on the upper wire back to eight to 13
buds. The number of buds left on the fruiting canes is
determined by plant vigor. If the grapevine is vigorous, leave
13 buds per cane. Leave only eight buds per cane if the
grapevine possesses poor vigor.
Prune the four canes on the lower wire the same as
those on the upper wire. When pruning is complete, no more
than 60 buds should remain on the grapevine. When
counting the number of buds on the grapevine, include both
the buds on the fruiting canes and those on the renewal
spurs.
wound defense mechanisms and promotes
compartmentalization and callus formation.
Avoid flush cuts when pruning trees. Flush cuts are
pruning cuts made as close as possible to the trunk or main
branch. Flush cuts produce larger wounds than cuts made
just below the branch collar. They also destroy the tree’s
natural process of walling off or compartmentalizing
wounds.
Large branch pruning
What is the proper way to prune a large
tree branch?
What type of equipment do I need to
prune trees and shrubs?
To prevent extensive bark damage, use a three-cut
procedure when pruning branches that are greater than 1
1/2 inches in diameter. Make the first cut 6 to 12 inches from
the main branch or trunk. Cut upward and go about onethird of the way through the branch. Make the second cut 1
to 2 inches beyond the first. As the second cut is made, the
weight of the branch will cause it to break at the pivot point
between the two cuts (the initial, bottom cut prevents the
branch from ripping off a large piece of bark as it breaks).
Make the final cut just beyond the branch collar and branch
bark ridge.
Proper pruning tools for a home gardener include hand
shears, lopping shears and a pruning saw.
Hand or pruning shears are generally used for cutting
stems (branches) up to 3/4 inch in diameter. There are two
basic types of hand shears. Scissor-type shears have
curved blades that overlap (scissor action) when making the
cut. Anvil-type shears have a sharp top blade that cuts
against a flat surface (anvil). Scissor-type shears are
generally preferred as they can make closer cuts and are
less likely to crush stems.
Branches from 3/4 to 1 1/2 inches in diameter can be
effectively cut with lopping shears. Lopping shears consist of
two blades attached to long handles. The long handles give
the gardener greater leverage so cuts can be made through
larger branches. Lopping shears are also excellent for
pruning difficult to reach places.
Use a pruning saw on branches larger than 1 1/2 inches
in diameter. Various types of pruning saws are available. A
pole saw can be used to prune hard-to-reach branches in
trees.
Sap from pruning cut
Sap is flowing from a pruning cut on my
maple tree. Should I be concerned?
Some tree species, such as maple, birch and elm, “bleed”
heavily when pruned in late winter or early spring. However,
the loss of sap does not harm the trees. The trees will not
“bleed” to death. Eventually the flow of sap will slow and
stop.
Painting pruning wounds
Pruning cuts
Should I paint the pruning wounds on
my trees?
Do not apply a pruning paint or wound dressing to
pruning wounds. The application of a pruning paint or wound
dressing does not prevent wood decay and may actually
interfere with the tree’s natural wound responses. Oak trees
are an exception to the no paint recommendation. To
prevent the transmission of oak wilt, oak trees should not be
pruned in spring and summer. If an oak tree needs to be
pruned during the growing season, for example to correct
storm damage, immediately (within 15 minutes) paint the
pruning cuts with a latex house paint. Winter (December,
January and February) is the best time to prune oak trees in
Iowa. There is no need to paint the pruning wounds when
oaks are pruned in winter.
Where should I make the final cut when pruning a tree
branch?
What is the proper way to prune fallbearing red raspberries in early spring?
Final cut of three-cut procedure is made just beyond
the branch collar and branch bark ridge.
When pruning trees, make the final cut just beyond the
branch collar and branch bark ridge. The branch collar is the
swollen area at the base of the branch. The branch bark
ridge is the dark, rough bark ridge that separates the branch
from the main branch or trunk. Pruning just beyond the
branch collar and branch bark ridge retains the tree’s natural
Popular fall-bearing red raspberry varieties include
‘Heritage,’ ‘Redwing,’ ‘Caroline,’ and ‘Autumn Bliss.’ Fallbearing red raspberries naturally produce two crops. One
crop is produced in summer on the previous year’s growth; a
second crop is produced in late summer or early fall at the
tips of the current year’s growth. Fall-bearing red raspberries
can be pruned two different ways in March or early April.
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One pruning option is to prune out all weak, diseased
and damaged canes at ground level. Leave the largest,
most vigorous canes. Cut back the tips of the canes that
remain. Remove approximately the upper one-third of the
canes. This option provides two crops during the year.
The second option is to prune all canes back to the
ground in late winter/early spring. This pruning option
produces a single crop in late summer or early fall. (The
summer crop is eliminated.) While only one crop is
produced, total crop yield is actually larger than the two-crop
system.
Red raspberries sucker profusely from their roots. To
prevent the planting from becoming a wide, unmanageable
thicket, red raspberries should be confined to a one- to twofoot-wide hedgerow. Shoots growing beyond the one- to
two-foot-wide hedgerow should be destroyed using a
rototiller or spade.
Please pass this on to anyone that may
be interested in joining us!
Chicago Flower & Garden Show
Monday, March 7, 2011
‘The Sport of Gardening: Field of Dreams’
The Chicago Flower Show is back at Navy Pier and
better than ever. Deb and I are going again this year and
hope you can join us. The flower show features display
gardens, tablescapes, educational seminars, cooking
demonstrations, and lots of gardening vendors in the
‘Marketplace’. More information on the flower show is
available at www.chicagoflower.com.
Our tentative schedule is to depart Cedar Rapids at 6:00
am (Wal-Mart on Blairs Ferry Road) and 6:30 am from
Marion (Wal-Mart at Highway 151 & 13). The bus will depart
Navy Pier at 6:00 pm and arrive in Cedar Rapids at
approximately 11:00 pm. We may arrange other pickup
points if needed.
The price for the bus and entrance to the flower show is
$65.00 per person. Make a check payable to ‘See The
World’ and mail to Zora Ronan, 5031 North Marion Road,
Central City IA 52214.
Deb Walser, 319 310-4258 or Zora Ronan, 319-4386838 or wadeborah@mchsi. zronan@aol.com
Caring for azaleas - - I recently received a
flowering azalea as a gift. How do I care
for it?
In the home, place the azalea in a brightly lit, cool
location. An ideal site is one near a window that receives
bright light (but no direct sunlight) and temperatures of 60 to
65 F.
An important aspect of caring for an azalea is proper
watering. Water needs can be determined with the finger
test. Check the potting soil daily with your finger. When the
soil surface becomes dry to the touch, water the plant until
water begins to flow out the bottom of the pot. The pots of
most azaleas are placed inside decorative pot covers.
When watering the azalea, carefully remove the pot
covering, water the plant in the sink, then drop the azalea
back into the pot cover.
If placed in a favorable location and given good care,
azaleas may bloom for two to four weeks.
Three FREE lectures presented by ISU Linn County
Master Gardeners.
Saving forced tulips - - Can I save tulips
that have been forced indoors?
Kirkwood Community College
Cedar Hall Room 234
6301 Kirkwood Blvd SW , Cedar Rapids, IA
Tulips and most other spring-flowering bulbs are
normally discarded after forcing. Attempts to save forced
bulbs usually are unsuccessful as few bloom again when
planted outdoors. Daffodils are an exception. If given good
care, forced daffodils can be successfully planted outdoors.
Plant care is important when attempting to save forced
spring-flowering bulbs. After blooming, remove the spent
flowers and place the plants in a sunny window. Water the
plants regularly until the foliage turns yellow. At this point,
stop watering and allow the foliage to wither and turn brown.
When the foliage is dead, carefully remove the bulbs from
the potting soil, allow them to dry for several days, then
store the bulbs in a cool, dry location until fall planting.
Contacts: Richard Jauron Horticulture 515-294-1871
rjauron@iastate.edu ;Willy Klein Extension
Communications and External Relations, 515-294-0662,
wklein@iastate.edu.
It Takes a Garden
presented by: Elvin McDonald
Monday • APRIL 4 • 6:30pm–8:30pm
Elvin believes it takes a garden to make a house a home.
And even a pot of cheerful pansies at the front door can
constitute a garden. Elvin will show gardens that have given
him inspiration as well as the transformation of his own
suburban yard in West Des Moines. His goal was to create
numerous places on the property that would invite him to
leave home without getting in the car. There are sitting
rooms in front of the house, and in back an Edwardian seat
arbor, a tea house, a dining pavilion and a deck that serves
as an outdoor family room. Elvin is Director of the Friends of
the Des Moines Botanical Center, prominent in American
horticulture since founding the Gesneriad Society in 1951 at
the age of 14. He has been named to the Garden Writers
Hall of Fame and is a recipient of the Hutchinson Medal for
lifetime achievement from the Chicago Botanic Garden,
author of more than 50 gardening books and the principal
designer for numerous public and private gardens for
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individuals such as Mrs. Robert F. Kennedy and actress
Glenn Close.
horticultural exhibition and education events in the state with
something for the home gardener to the professional
horticulturist.
The 2011 Expo will feature nationally recognized keynote
speakers Felder Rushing, an award-winning author and
founder of the Slow Gardening® concept, and Rita
Randolph, nationally respected container gardening diva,
as well as experts from across the state and region lecturing
about everything from growing and cooking mushrooms,
arranging flowers, garden design, green roofs and much
more.
For more information, visit www.iowahort.org. It’s a green
place to be!
Top Ten Gardening Blunders
presented by: Don Engebretson
Wednesday • APRIL 13 • 6:30pm–8:30pm
Every gardener is sure to discover that startling success
sometimes goes hand-in-hand with staggering failure. Don
wants to help gardeners severely limit any “staggering
failure”. His list of blunders meets three important criteria: it
must be a common mistake, as common as crabgrass, it
must impart a truly gruesome effect on one’s landscape and
it must be a blunder that Don has made at least twice during
his 20+ years as a gardener! With a strong emphasis on
design do’s and don’ts, you will learn how to create a
functional, beautiful landscape on your property. Don is a
nationally recognized authority on landscaping and garden
design and speaks frequently at industry events across the
United States. He is an author, field editor and garden scout
for Better Homes and Gardens and spent three seasons as
the gardening expert on HGTV’s TIPical MaryEllen show, a
six-time winner of the Garden Writers Association Garden
Globe Award for excellence in garden writing and operates
the landscape design and installation company Renegade
Gardener Landscaping.
Delaware County Master Gardeners
Present “Mondays In March”
Submitted by Marcia Banyas
The Delaware County Master Gardeners are preparing
to present four interesting programs
during the Sixteenth Annual "Mondays
in March" series. This year’s speakers
will provide a variety of subject matter
sure to captivate the interest of all
types of gardeners.
Sessions begin at 7:00 p.m. and are
held at Our Savior’s Lutheran Church,
114 Guetzko Court, Manchester. The
public is invited and encouraged to
attend one or all of the sessions. A
$2.00 freewill offering per session is
suggested.
20 of My Favorite Native Trees & Shrubs
presented by: Michael Yanny
Wednesday •APRIL 20 • 6:30pm–8:30pm
Learn about 20 outstanding native plants that you should
know about including plants with outstanding fall colors,
some with fabulous flowers, some whose branches are
covered with golden blooms in October and trees that are
vital to wildlife. Propagation, plant culture and growing
techniques will be addressed. Come learn a little and laugh
a lot! Michael has been the plant propagator at Johnson’s
Nursery, Inc. in Menomonee Falls, Wisconsin since 1980,
has been responsible for developing numerous tree and
shrub cultivars as well as instrumental in developing an
extensive line of local ecotype native plants.
The Creative Gardening Series is presented by the Linn
County Extension Master Gardeners, a dedicated group of
volunteers, trained by Iowa State University. They share
their horticulture knowledge with the community through
demonstrations, classes like the Creative Gardening Series,
events and the Hortline. For unbiased, research-based
answers to your horticulture questions call the Hortline:
319.447.0647.
The 2011 Mondays in March dates and programs
are:
March 7 – Keith Kovarik “Tried, True and Best
of the New for 2011”. Since 1996, Keith & Kelli
Kovarik, owners of K & K Gardens, have been offering
Northeast Iowa the largest selection of new and
unusual perennials, annuals, woody ornamentals,
water garden plants and equipment, accessories,
garden gifts, and a diverse selection of hosta and
daylilies. K & K Gardens has nearly one acre of
enchanting perennial gardens displaying endless
ideas for all levels of the gardening enthusiast.
Located on the southern edge of Northeast Iowa's
rolling hills in the small community of Hawkeye, Iowa,
the retail garden center and nursery has been referred
to as a "must see" destination for every caliber of
gardener. On March 7 Keith will showcase his
personal tried and true favorites, incredible new or
near new introductions of several perennials, shrubs,
trees, hostas, and daylilies. Additional information
about the Kovarik’s and K & K Gardens can be found
at www.kkgardens.com
March 14 – James O. Durbin – “Getting Rid of
the Grass and Attracting the Birds” Jim has been
involved with Cedar Rapids Audubon since 1989
serving as president, board member and is currently
the membership chairman and treasurer. He is a
volunteer with the Linn County Conservation
All-Iowa Horticulture Expo III
In partnership with its 27 affiliate organizations and Iowa
State University Extension, the
Iowa State Horticultural Society
(ISHS) is proud to present AllIowa Horticulture Exposition III
- its third gala exhibition of
horticulture, which includes
lectures and diverse trade show
exhibits showcasing the many
facets of Iowa horticulture. The
2011 All-Iowa Horticulture
Exposition is scheduled for March 25-26 at the Bridge View
Center in Ottumwa, IA. It aims to be one of the premiere
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it right. Since the late 80's, he has been involved with the
design and installation of over 800 water gardens and
features. Jamie has written over a dozen magazine articles
on several different aspects of water gardening and the
book "All About Garden Pools and Fountains". He is
currently writing another book on the subject. On March 28
Jamie will show some of the water features available to
gardeners. He will discuss what you need to consider
before starting a project, some construction techniques, and
discuss fish and plants suitable for water features.
Questions about Mondays in March can be directed to the
Delaware County Extension Office: 563-927-4201 between
the hours of 8 and 4:30.
We look forward to seeing you each Monday in March!
department presenting bird classes and studies of
species in some of the parks. Jim has been involved
with the DNR doing Henslow’s Sparrow studies in
2004/5/6 at Pleasant Creek Lake State Recreation
Area. His interests include photography primarily with
flowers, birds, butterflies and dragonflies. His spare
time is spent landscaping his backyard that includes
ponds. In 2007 Jim created a website
www.insectsofiowa.com that has pictures and
collection data of moths, butterflies, and
www.birdsofiowa.com that has birds, fungi, mammals
and amphibians. On March 14 Jim will discuss options
for turning your backyard into a haven for the birds.
Throughout his presentation he will discuss plants to
use, water features that will help and seeds and other
items to feed.
Annual Green Scene Garden
Symposium
March 21 – Roger Hunt – “Trees and Our Need for
Species Diversity in Our Yards and Public Spaces”
Roger, who was raised in Manchester and graduated from
West Delaware, is a Field Coordinator for Trees Forever. A
graduate of Landscape Architecture from Iowa State
University, he has practiced as a landscape architect in
Minneapolis/St. Paul Minnesota, Seattle Washington and
now from his Suntree Farm home/office, bringing a unique
perspective as both a landscape architect and farmer. With
Trees Forever, he is responsible for facilitating and
coordinating projects in three program areas: Community,
Roadways and Rural. In this capacity he works with
approximately 20 communities in Southeast Iowa, numerous
buffer partners, and on watershed planning projects around
the state. He provides design guidance to all program areas
and to other field coordinators working with Trees
Forever. Roger is a Member of the American Society of
Landscape Architects and the ASLA Iowa Chapter (past
Board Member). He operates Suntree Farm (a purebred
Angus livestock and crop farm) near Columbus. On March
21 Roger will discuss problems we have had in the
past/present and how that affects our tree canopy, what we
should be doing now, and will introduce us to some Trees
Forever Programs that can help.
March 28 – Jamie Beyer- “Water Features, From the
Simple to the Stupendous” The very popular subject of
adding water features to a garden is one that Jamie Beyer
brings a lot of knowledge and enthusiasm to. Jamie, who
grew up in Jefferson, Iowa is a Lifetime Master Gardener
from the Ames/Boone area and is founder and Past
President of the Central Iowa Water Garden Association.
Water gardening has been a passion of Jamie's for over 45
years and, currently, he has three 10,000 gallon ponds and
one 27,000 pond which contains many kinds of water plants
and fish. He combines this experience with his Master's
Degree in Fish and Wildlife Biology to become uniquely
qualified to be one of the Midwest’s foremost experts on the
subject. His broad background of fisheries, dynamics of
water, wildlife ecology, and horticulture gives him impressive
credentials. Jamie frequently speaks and writes on all
aspects of water features and water gardening to gardeners
in the Midwest. In addition, he also has a
consulting/installation business, called Midwest
Waterscapes, which he works as a water garden, fountain
and pond consultant/installer. Jamie has considerable
experience installing ponds, diagnosing water garden
problems, teaching classes and helping do-it-yourselfers, do
By Brenda Clark, Green Scene Publicity
On Saturday, March 12, 2011 at the Waterloo Center for
the Arts, 225 Commercial Street, Waterloo, Iowa. $20.00 fee
includes 5 presentations and lunch. A Gardener’s Market
will also be open featuring displays from the speakers and
products from some area retailers. Pre-registration is
recommended. Make checks payable to Green Scene
Symposium and mail to P.O. Box 2004, Waterloo, IA 50704.
Registration is from 8-8:30 a.m. and the day concludes at
2:30 p.m.
Topics:
8:30-9:20 -- Plant Propagation by Kelly Conrad; 9:3010:20 -- Color in the Garden by Jolene Rosauer; 10:3011:20 -- Ergonomics in Your Garden by Dr. Michael O’Hara;
11:30-12:30 – LUNCH BREAK; 12:30-1:20 – What’s New in
Hostas, by Josh Spece; 1:30-2:30 – Flower Arranging by
Jackie Frink.
Green Scene is a local non-profit volunteer organization
that has given over a half-million dollars to Black Hawk
County for tree planting and county beautification projects
since its inception in 1976.
Pruning Raspberries in Late
Winter/Early Spring
By Richard Jauron, Department of Horticulture
Proper pruning of raspberries is essential. Pruning
produces higher yields, helps control diseases, and
facilitates harvesting and other maintenance
chores. Pruning procedures are based on the growth and
fruiting characteristics of the plants.
The growth and fruiting characteristics of the raspberry
plant are rather unique. The plant's roots and crown are
perennial, while the stems or canes are biennial. Each
spring, purple, black, and red raspberries produce new
canes from buds located at the base of the previous year's
growth. Red raspberries also produce new shoots from buds
located on their roots. The individual canes live 2 years and
then die.
The shoots of purple, black, and summer-bearing red
raspberries are strictly vegetative during their first growing
season. The following year, these same canes flower,
produce fruit, and then die.
The growth and fruiting characteristics of fall-bearing red
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raspberries are slightly different. Fall-bearing varieties
naturally produce two crops. The first crop is produced in
late summer or early fall at the tips of the current season's
growth. The following year, a summer crop is produced on
the lower portions of these same canes. After the second
crop, the canes die.
A number of yellow raspberry varieties are also
available. With the exception of fruit color, the growth and
fruiting characteristics of yellow raspberries are identical to
red raspberries.
All raspberries should be pruned in March or early April.
Late winter/early spring pruning procedures for the different
types of raspberries are outlined below.
Things are relatively quiet in the insect world this time of
the year but we have still gotten a few samples:
Carpenter ants - having active ants in the house in the
middle of winter is a strong indication there is a colony
located indoors. Don't panic though carpenter ants don't eat
wood, they just hollow out rotten wood. Colonies are usually
located where a water leak has damaged wood.
Millipedes - millipedes indoors can be an annoyance,
but they are harmless and will not live very long in the dry
environments indoors.
Can row covers stop cucurbit
bacterial wilt, and are they cost
effective?
Summer-Bearing Red Raspberries
Remove all weak, diseased, and damaged canes at
ground level. Leave the most vigorous canes, those
approximately 1/4 inch in diameter when measured 30
inches from the ground. After thinning, remaining canes
should be spaced about 6 inches apart.
Also, prune out the tips of the canes which have died
due to winter injury. Cut back to live tissue. If the canes
have suffered little winter dieback, remove the top 1/4 of the
canes. Cane-tip removal or "heading-back" prevents the
canes from becoming top heavy and bending over under the
weight of the crop.
Red raspberries sucker profusely from their roots. To
prevent the planting from becoming a wide, unmanageable
thicket, red raspberries should be confined to a one- to twofoot-wide hedgerow. Shoots growing beyond the one- to
two-foot-wide hedgerow should be destroyed using a
rototiller or spade.
Fall-Bearing Red Raspberries (Two Crop System)
Follow the same pruning procedures as described for
the summer-bearing red raspberries. This pruning option
provides both a summer and fall crop.
Fall-Bearing Red Raspberries (One Crop System)
Prune all canes back to ground level in March or early
April. While the plants won't produce a summer crop, the
late summer/early fall crop should mature one to two weeks
earlier. Also, total crop yield is typically larger utilizing the
one-crop system versus the two-crop system. Maintain the
plants in a 1- to 2-foot-wide hedgerow.
Yellow Raspberries
The pruning of summer-bearing and fall-bearing yellow
raspberries is identical to their red raspberry counterparts.
Black and Purple Raspberries
Remove the small, weak canes, leaving only four or five
of the largest, most vigorous canes per clump or plant. Cut
back the lateral (side) branches to 12 inches in length for
black raspberries and 18 inches for purple raspberries.
When pruning is completed, remove the pruned material
from the garden area and destroy it. Removal and
destruction of the pruned material helps control raspberry
diseases, such as anthracnose and spur blight.
By Erika Saalau, Mark Gleason, and Jean Batzer,
Department of Plant Pathology
Bacterial wilt is a major challenge for North Central
Region cucurbit growers. This disease, caused by the
bacterium Erwinia tracheiphila, can wreak havoc on all types
of cucurbit crops except watermelon. Leaves and stems wilt
and dry up, and infected plants typically die. See photo
below.
Cucumber beetles are part of the bacterial wilt story.
Two species, striped and spotted cucumber beetles, carry
the bacterium from plant to plant, and infection often
happens through beetle feeding wounds. Fighting bacterial
wilt means fighting cucumber beetles; the main defense
against the disease is stopping the beetles.
Many strategies have been tried to beat the beetles.
Most growers rely on insecticides, but chemical warfare can
require many applications per year, which is expensive and
may also damage non-target insects, including the bees that
pollinate cucurbit crops. Other tactics, such as trap crops
and chemical lures, are still in the experimental stage.
Organic growers have an especially difficult struggle to grow
highly wilt-susceptible crops such as cucumber and
muskmelon, because organically approved insecticides are
not very effective against cucumber beetles. In fact, some
organic growers won’t plant these highly susceptible crops
due to worries about bacterial wilt.
Row Covers and the Fight Against Bacterial
Row covers are made of lightweight fabric and are
suspended above the plants on wire hoops. See photo
below. All edges of the fabric are secured in the soil to hold
the fabric in place and to exclude pests. Spunbond polymer
row covers such as Agribon(R) and Reemay(R) have gained
a foothold with North Central Region cucurbit producers
because the covers warm the soil, speed up crop maturity,
and protect against extreme early-season weather (frost,
hail, wind, heavy rain).
Row covers also have potential as a defense against
bacterial wilt because they keep out cucumber beetles. As
the soil warms up in the spring, cucumber beetles emerge
from the ground with one mission: zero in on cucurbits. As
they munch on the leaves, bacteria from their mouthparts
and feces (frass) end up on the feeding wounds and enter
the plants. Soon the plants start to wilt. Row covers keep out
the beetles during the vulnerable early-season period.
Most growers remove row covers once flowering starts.
Our research at Iowa State University (ISU) several years
ago showed that deploying row covers from transplanting
until the start of flowering could delay bacterial wilt. But
Plant and Insect Diagnostic Clinic
Update - February 9, 2011
By Laura Jesse, Plant & Insect Diagnostic Clinic
The following are highlights and updates about samples
and questions recently received in the Clinic:
Insects
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sometimes the wilt would catch up by the end of the season,
so the end result was still dead plants.
What if the row covers could stay in place a bit longer?
Researchers in Canada and Africa found major insect-pest
control benefits if they kept the row covers in place for 10
more days past the start of bloom. We thought this delayedremoval idea was worth a try in Iowa.
Research Approach
With funding from North Central IPM Center and EPAPESP grants, we ran 6 field trials at ISU research farms in
Gilbert and Muscatine (central and eastern Iowa
respectively) in 2007, 2008, and 2009. Muskmelon (cv.
Athena) seedlings were transplanted to field plots and
immediately after transplanting, seedlings were covered with
Agribon® AG-30 row covers supported by wire hoops, with
the edges buried in soil.
Treatments were:
1. Row covers were removed at start of flowering.
2. Row cover ends were opened at start of flowering to
enable pollinator access, and covers were removed 10
days later.
3. After a bumble bee hive (Koppert Biological Systems
Inc.) was inserted under one end of the row cover at
start of flowering, the row cover was re-sealed and then
removed 10 days later.
4. No row covers (control).
No insecticide applications were made during these
trials, so that we could see the full effect of the row cover
practices. After row cover removal, were monitored the
plants every week until the start of harvest for incidence of
bacterial wilt (percent of plants that died).
Row covers are not cheap, and they take time to set up
and remove. But can they pay for themselves? To begin to
answer this question, we made a partial budget to analyze
costs and returns for each treatment. Revenue was
calculated by extrapolating mean yield per subplot to a perhectare basis, and multiplying by local wholesale ($3) and
direct retail prices ($6) per 5-lb melon. We calculated net
returns by subtracting production cost of each treatment
from gross income on a per-hectare basis.
In Iowa and nearby states, bacterial wilt occurs
sporadically; sometimes devastating, and sometimes nearly
absent. How can the sporadic nature of the disease be
factored into economic calculations? As a first step, we did a
sensitivity analysis across treatments that compared several
scenarios for the frequency of occurrence of years with
bacterial wilt: 0, 5, 10, 15, and 20 of 20 years.
Results
Bacterial wilt appeared in the three field trials held during
2007 and 2008. At Gilbert in 2007 and Muscatine in 2008,
delaying row cover removal by 10 days resulted in
significantly less bacterial wilt than when row covers were
removed at the start of flowering. In the trial at Gilbert in
2008, all row cover treatments suppressed bacterial wilt
effectively and resulted in equivalent marketable yield that
exceeded that in the non-covered control. In 2009, bacterial
wilt was absent in all three trials and row cover treatments
had little impact on yield.
Delaying row cover removal and opening row cover ends
increased costs by a further 1% due to labor, whereas
inserting bumble bee hives raised costs by a total of 18%
due to purchase of bumble bees and labor to install them
under row covers. For trials in which bacterial wilt occurred,
average annual returns under both price scenarios were
much higher for the delayed-removal strategies than for
either the removal-at-anthesis (the current standard
commercial practice) or no-cover controls. All row cover
strategies reduced projected returns in site years without
bacterial wilt. In the sensitivity analysis, the highest annual
returns occurred under the no-disease scenario for all
treatments, and returns declined as the proportion of years
with wilt outbreaks increased.
Take-Home Points
Our Iowa field trials showed that delaying row-cover
removal by 10 days can provide season-long protection of
muskmelon against bacterial wilt. This strategy proved to be
an effective alternative for controlling bacterial wilt and
cucumber beetles without insecticide applications. It could
replace or reduce the need for insecticide sprays, and could
be especially valuable for organic growers, who lack
effective insecticides against cucumber beetles.
Results of the partial budget analysis suggest that when
bacterial wilt epidemics occurred, the delayed-removal row
cover strategy would deliver more consistent returns than
either removing them when flowering starts or not using
covers at all. The sensitivity analysis suggested that cost
effectiveness of the delayed-removal strategy is affected by
how often bacterial wilt outbreaks occur. The strategy was
economically advantageous when bacterial wilt occurred in
half or more of the growing seasons, but was a drag on
returns when wilt was absent or less frequent.
For growers the advantage of using row covers will
depend not only on the likelihood of disease occurrence but
also on planting date, melon prices, availability of labor, and
viability of effective alternatives to suppress the disease.
Research data table and graphs are available from the
authors. Phone 515-294-0579 or Email
mgleason@iastate.edu
Symptoms of
bacterial wilt in
muskmelon.
Photo by Jean
Batzer.
Row cover on wire
hoops over muskmelon
with ends open to allow
entry of pollinators.
Photo by Erika Saalau.
Iowa State University and U.S. Department of
Agriculture Cooperating Extension programs are
available to all without regard to race, color,
national origin, religion, sex, age, or disability.
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