Yard & Garden Line News Volume 7 Number 18                                                               December 1, 2005

Features this issue: Plants for Winter Interest Cockroaches in Multi-Unit Dwellings Become a Tree Whiz! 2006 Garden Calendar Is Available Editorial Notes

Plants for Winter Interest
Nancy Rose, Regional Extension Educator, Horticulture

Viburnum fruit. Photo credit: Nancy Rose

Dingy white. Gray. Beige. Is this the dull color palette that greets you when you gaze out into your yard during the winter? Does the lack of color and texture in your landscape make you think that winter hibernation is not such a bad idea? Well, the good news is that with some thoughtful plant slection you can have a winter landscape worth staying awake for.

Landscape plants can provide winter interest in a number of ways. Colorful, persistent fruit can add cheerful ornamentation to trees and shrubs. Even seedheads in shades of brown can add texture and visual interest. Winter stems and bark can provide bright colors, a rich metallic sheen, or the textural accent of papery curls. The long leafless season also gives us the opportunity to observe the branching patterns of deciduous plants, and the intricate fretwork of snow-dusted branches can be quite beautiful. And, of course, what would the winter landscape be without the pleasing color and substance of evergreens?

Let's start our redecorating job with some colorful fruit. As every fashion maven knows, a dash of bright color adds pizazz to any color scheme. Red fruit makes a particularly striking accent in a winter landscape dominated by white snow and neutral shades of gray and brown. Fortunately, there are several excellent shrubs and small trees that provide bright red fruit through the winter. One of the best is American cranberrybush viburnum (Viburnum trilobum, also known as highbush cranberry). This hardy large shrub bears clusters of fruit that start turning red in early fall and persist all winter. The fruits are edible but have a slightly acrid aftertaste; perhaps this is why birds ignore the fruit until spring when it softens and ferments a bit.

Flowering crabapples can be a great source of colorful fruit, but only if you select the right cultivars. While all crabapple cultivars are lovely during their bloom period (often a mere 3-4 days, perhaps a week if the weather is just right), not all of them have colorful, persistent fruit. Some older cultivars are notorious for having overly large fruit that ripens and falls in late summer, but there are plenty of wonderful cultivars that are festooned with small, brightly colored fruit through most of the snowy season. 'Donald Wyman' wins the award for most persistent fruit - dozens of its bright red, 3/8 inch fruits are still present when the tree blooms in May.

'Annabelle' hydrangea. Photo credit: Nancy Rose

Many shrubs, perennial flowers, and ornamental grasses provide winter interest in the form of dried flowers and seedheads. While the color range is limited to browns, tans, and off-white, these flowers and seedheads add considerable textural interest to yards and gardens, and are often especially attractive with caps of new fallen snow.

Noted for hardiness and white summer flowers, both smooth and panicled hydrangeas (Hydrangea arborescens, H. paniculata) leave clusters of papery florets decorating their stems into the winter. The seedheads of many perennial flowers can be left in the garden to provide winter interest, as well as seeds for small birds. The bold brown domes of purple coneflower (Echinacea purpurea) and the sturdy flat plates of sedum (Sedum 'Autumn Joy' and other cultivars) are two of my favorites. Many cultivars of the ornamental grass Miscanthus display airy whitish seed plumes that catch the low-angled winter sunlight; these soft seedheads are spectacular combined with evergreens and plants with colorful fruit.

Bark is highly noticeable in the winter, so it's worth seeking out some shrubs and trees with notable stems and trunks. Brightly colored bark really stands out in the winter landscape, and one of the most colorfully clad shrubs available is also one of the easiest to grow. This shrub is red-stemmed dogwood (Cornus stolonifera, synonym C. sericea), a 6-8' tall shrub that is hardy to -40 or lower. The cultivar 'Cardinal', a University of MN introduction, is noted for having especially bright cherry red stems. There are also several shrub dogwoods that have bright yellow stems rather than red, such as Cornus alba 'Bud's Yellow'. You'll get a more colorful plant from any of these if you remember to prune out some of the oldest stems each year - this encourages more new stems which have the brightest winter color.

Trees with shiny or curly bark add winter interest also. For shiny bark, nothing beats Amur chokecherry (Prunus maackii), a 15-25' tall tree with gorgeous copper colored bark. It's plenty cold hardy and, in fact, grows better in colder climates than in the steamy South. Trees with curly bark include river birch (Betula nigra), a native tree with masses of shaggy, peeling bark in shades of cream, tan, and pinkish orange. River birch prefers evenly moist soil that's slightly acidic.

'Flame' willow winter stems Photo credit: Nancy Rose

Its easy to see how plants with screaming red fruit or stems add to the winter landscape, but the discerning gardener can also appreciate subtler traits like intriguing branching habits. Plants with horizontally tiered branches such as pagoda dogwood (Cornus alternifolia) or interlacing branches like those seen in a patch of staghorn sumac (Rhus typhina) provide pleasing architectural patterns, especially when outlined with a fresh sifting of snow.

Though I've left them til last, there's no question that evergreens are vital to the well designed winter landscape. They provide some green color and a nice solidity on their own, and they combine well with any of the other winter interest plants I've mentioned. A nice dark green spruce or arborvitae makes a great backdrop for brightly colored fruit or stems, or the plumey seedheads of grasses. The woody cones borne by many evergreens and the blue, berry-like cones of certain junipers add a decorative note as well.

Spend some time looking out at your yard this winter. Could you use a splash of color at the edge of the deck or patio? How about some tall evergreens to frame a view? Wouldn't it be nice to admire the burnished copper trunk of an Amur chokecherry every time you look out the front picture window? Do some planning now. Then, when spring comes, do some planting to help make your landscape beautiful in ALL seasons.

Colorful fruit:
American cranberrybush viburnum, Compact American cranberrybush viburnum
Staghorn sumac and smooth sumac
Barberries
Winterberry (cvs. include 'Red Sprite', 'Shaver', 'Afterglow', 'Aurantiaca', 'Winter Red')
Crabapples ('Donald Wyman', 'Red Jewel' 'Sugartyme', 'Red Splendor', 'Indian Magic', 'Ann E.', 'Adams', 'Firebird')

Colorful stems:
Red stemmed dogwood ('Cardinal', 'Ruby', 'Baileyi', 'Sibirica')
Yellow stemmed dogwood ('Bud's Yellow', 'Silver and Gold')
Flame willow (Salix 'Flame')
Coral bark willow (Salix alba 'Britzensis')

Shiny bark:
Amur chokecherry
China Snow lilac (Syringa pekinensis 'China Snow')

Peeling bark:
River birch
Three flowered maple (Acer triflorum)

Seed heads:
Coneflowers
Sedums
Martagon lilies
Balloon flower
Hydrangeas
Japanese tree lilac
Grasses - Miscanthus ('Purpurescens', 'Silver Feather', 'Malepartus', 'Gracillus')

Branching habit:
Pagoda dogwood
Sumacs
Japanese tree lilac
Amur maple
Burning bush (Euonymus alatus)

Cockroaches in Multi-Unit Dwellings
Jeffrey Hahn, Assist. Extension Entomologist

German cockroach adults, nymphs, and egg capsule Photo credit: Univ. of Nebraska

One of the most disliked insects in the urban environment is the cockroach. In Minnesota, the most common species is the German cockroach. You may also occasionally find brownbanded, Oriental, or American cockroaches. While these insects can be challenging to eliminate from houses they are even more difficult to eradicate from multi-unit dwellings, like apartment buildings.

Not only are cockroaches a nuisance but they are also an important health concern. They are a significant source of allergens and are the number one source of asthma amongst children, especially those in inner city locations. Cockroaches can give off a foul odor and can also contaminate food, pots and pans, utensils, and counter surfaces. They can potentially transmit disease organisms, such as Salmonella and E. coli which can increase the risk of food poisoning and diarrhea.

Pest cockroaches do not live outdoors and rarely move between unattached buildings. However, they can be easily transported via bags, boxes, purses, luggage, furniture, and appliances from infested buildings into unifested ones. Once in a multi-unit building, they can easily disperse along plumbing and electric wiring and move into adjacent units.

If you see an insect and are concerned that it is cockroach, make sure you have correctly identified it. Not every ‘bug' people see is necessarily a cockroach. For example western conifer seed-bugs, crickets, ground beetles, and long-horned beetles can be confused as cockroaches. If you see a slow moving insect in the middle of the day, it is not likely to be a cockroach.

You can identify a cockroach by its oval and flattened body with a head that is hidden when viewed from above. It also possesses long antennae (about the length of its body) and has strong legs that are covered with spines. The average cockroach (German and brownbanded cockroaches) are about 1/2 inch long as an adult with the immature nymph being as small as 1/16th inch long. Cockroaches avoid light and are most active at night. If you walk into a room and turn on the light at night and see an insect scurry away quickly, that is probably a cockroach.

Cockroaches feed on essentially any food material as well as non-food items including soap, glue, and book bindings. Even more important than food, cockroaches, especially German cockroaches, require a source of moisture. They will not survive long if they do not have access to water.

Cockroach sticky trap under kitchen sink Photo credit: Jeff Hahn

Cockroaches prefer to live in tight confined spaces. A German cockroach in particular prefers a harborage near water. These cockroaches are most commonly found in kitchens and bathrooms. Specific areas include cracks and voids around sinks, under refrigerators and stoves, and cracks and voids around cupboards and cabinets. Once a harborage has been found, and a cockroach spends time there, a chemical in its feces (an aggregation pheromone) attracts other cockroaches to the same site. Once German cockroaches have found a favorable harborage with food and water nearby, they do not stray far from it except in cases of heavy infestations.

Successful elimination of cockroaches in multi-unit dwellings requires a multi pronged approach which includes monitoring, sanitation, harborage reduction, and insecticide applications. It is very important that tenants are educated about cockroaches and there is communication between the pest control technicians, building owners/landlords, and the tenants as to the role each of them have in successfully eliminating cockroaches.

It is very important to understand how severe a cockroach problem can be in a building. You can determine this by questioning all of the tenants to discover which units have sighted cockroaches. They should also be looking for cockroach egg capsules which are dark-colored and roughly the size and shape of a dry kidney bean. You should also set out sticky traps to see if cockroaches are trapped in any places that were not otherwise reported to be infested. The more traps that are set out the more accurate the information. Traps not only can indicate that cockroaches are present in a particular apartment but in what rooms and their relative numbers.

Depending on how widespread a cockroach problem is can determine how many units are treated. Because cockroaches can move between units and floors via plumbing, electrical wiring, and other utility lines, it is important to think beyond just the infested apartments. If there are only a couple of infested units present, you may not need to treat the entire building. At minimum you should treat the infested apartments and the adjacent ones and monitor the rest of the units. The entire building is likely to need treatment when it is more thoroughly infested.

Sanitation and harborage reduction are important in a successful cockroach pest management plan. This is the responsibility not only of the pest control service but also the residents of the building and the owner/landlord. While it is unlikely that you can control a cockroach problem solely by reducing or eliminating food, water, and favorable places to live, you can significantly stress cockroaches and increase their exposure to insecticides when the cockroaches' access to these things are limited.

You can practice sanitation by promptly cleaning dishes and utensils when you are done using them; never leave dirty dishes out overnight. Also be sure to put away food by either storing them in plastic, glass, or metal containers with tightly fitting lids or by putting them into the refrigerator. Seal garbage in plastic bags and remove it daily. Clean counter tops and stove tops to remove food residue. Also clean along the sides and underneath stoves to remove food particles and grease that may be present. Sweep or vacuum floors and other areas where crumbs may accumulate. Rinse cans and bottles saved for recycling. Don't leave dry pet food or water out over night. Repair any leaking plumbing and properly vent any rooms where excess moisture exists.

Although, it is difficult to reduce all harborage areas, you can have some impact on cockroach numbers by removing piles of newspapers, corrugated boxes, bags and other clutter. Also seal cracks and spaces, e.g. around baseboards, where cockroaches may hide. It is particularly important in multi-unit buildings to seal spaces where plumbing or electrical wiring goes through walls. You can also place escutcheon plates at points where plumbing enters the walls.

You can remove cockroaches and egg cases, particularly when high numbers exist, with a vacuum cleaner. Because of the risk of cockroach debris which could harm human health, use vacuums with a high efficiency particulate air (HEPA) filter when possible. Sticky traps are not very useful in controlling cockroaches, just use them to monitor cockroach numbers.

Clean dishes and put food away Photo credit: Mark Ascerno

Insecticides should be applied by a licensed and experienced pest control technician. They will typically use either one of two types of insecticides to control cockroaches, baits or sprays. Either can effectively eliminate cockroaches. They may also supplement these treatments with applications of dusts like boric acid or diatomaceous earth. The use of insecticides, while important in a cockroach control program, is not a magic bullet. You don't just squirt some product into a general area and expect it to kill all of the pests. It takes experience and knowledge of cockroach biology to properly and precisely apply insecticides into their harborage areas where they will have the most effect.

When a pest control service is treating a building, tenants need to cooperate with any requests made by the company, e.g. if they are asked to move items like food and dishware out of cupboards. Tenants and landlords should refrain from applying any insecticides themselves as it could interfere with the efforts made by the pest control technician.

Owners of apartment buildings and other multi-unit dwellings have an obligation under law to perform reasonable repairs to apartments which includes insect control. Tenants that discover pests can contact a city inspector to examine the problem. The inspector then contacts the landlord and gives them a deadline to correct the issue. Tenants can also contact their landlord directly about the insects by providing them a written notice of the problem. The landlord then has 14 days to correct it. The tenants need to cooperate with the landlord by allowing them access to their apartment. If the problem has not been addressed within that time, the tenant has the right to file court action. They can do this on their own or they can seek help from a local Legal Aid office or similar organization.

Get the low down on this month's insect pests at Insects
http://www.extension.umn.edu/projects/yardandgarden/EntWeb/Ent.htm

Become a Tree Whiz! Minnesota Tree Care Advior Training Starts in February.
David Hanson, Research Specialist, Urban and Community Forestry

Gary Johnson prunes for TCA class. Photo credit: Dave Hanson

Announcing the 2006 Minnesota Tree Care Advisor (TCA) Training! The TCA Program is similar to the Master Gardener program in that volunteers pay a fee, $87.50 this year, and receive 30 classroom hours of both hands on and in class training with local experts.

The training takes place in Green Hall on the St. Paul campus of the University of Minnesota from 8:30 am - 3:30 pm on February 18th, February 25th, March 4th, March 11th, and March 18th. The classes focus on tree and shrub care within an urban environment. Topics covered include, but are not limited to: plant selection based on site, how to prune, common tree insects and diseases, and diagnostic procedures.

In exchange for the training and support, volunteers are expected to perform 50 hours of community service the first year and 25 hours each additional year. Often, these volunteer hours are consistent with Master Gardener volunteer activities and are not in addition to required Master Gardener hours. In order to keep you up to date on current tree related research and news you will receive a quarterly newsletter, a website with tons of resources, and quarterly update training sessions on "hot topics."

Interested? Please visit the website at http://www.mntca.org to find out more about the program. While there you can fill out the online application or print one to mail in. You can also call Dave Hanson at 612-624-1226 for program assistance. We look forward to hearing from you.

2006 Garden Calendar Is Available

2006 Calendar

Our 2006 Minnesota Gardening Calendar is the perfect gift for your gardening friends and relatives. All new photographs and gardening tips celebrate each month of 2006. A "must" for anyone that enjoys gardening and looks forward to another year of our calendar!

This calendar has:
* Beautiful full color photography
* Expert gardening advice
* Proven indoor and outdoor gardening pointers for our region
* A feature section on perennials that bloom in late summer and fall

To preview some of the photography featured, click here: http://www.extension.umn.edu/distribution/horticulture/components/DG8206a.html

Shop on line at: http://shop.extension.umn.edu/PublicationDetail.aspx?ID=1721

Editorial Notes

Winter arrangement. Photo credit: Beth Jarvis

It appears winter has arrived. The Twin Cities had temperatures in the low 50s and rain the Sunday after Thanksgiving, less than a week ago. Then the temperatures dropped into the 20s for highs and snow fell. This picture was taken right outside one of the entrances to the Oswald Visitors Center at the Arboretum. It features dried 'Purple Majesty' millet, evergreen boughs, dogwood stems and dried black-eyed Susans.

In the January issue, Bob Mugaas will share some information on grass seed selection. In February, Bob will discuss the non-delectivem organic herbicide trials he conducted. This study included citric acid, among other options. For March or April,Bob Mugaas will provide the data from the two year perennial evaluation program that he, Janna Beckerman and a host of Master Gardeners conducted.

Please feel free to cut and paste any of the articles for use in your own newsletters. All we ask is that you give our authors credit.

Back issues Yard & Garden Line News are on the Yard & Garden Line home page at www.extension.umn.edu/yardandgarden/.

Deb Brown answers gardening questions on Minnesota Public Radio's (MPR) "Midmorning" program on the first Friday of every month at 10 a.m. The program is broadcast on KNOW 91.1 FM, and available state-wide on the MPR news radio stations. (Scroll down for map.)

For plant and insect questions, visit http://www.extension.umn.edu/askmg. Thousands of questions have been answered, so try the search option in the black bar at the top left of the board for the fastest answer.

If you would like to receive an e-mail reminder when the next issue of the Yard & Garden Line News is posted to the web, just send an e-mail to: listserv@lists.umn.edu (note: the second E in listserve is omitted), leave the subject line blank, then in the body of the message, type: sub yglnewslist or to unsubscribe, enter: unsub yglnewslist



Happy gardening!

Beth Jarvis
Yard & Garden Line Project Coordinator


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