Green Roofs
1
Putting Down Roots: By Cliff Johnson
3
Invasive Plants
5
Watching The “Pine” Tree Die
6
European Sawfly
8
State’s Ash Trees Face Mortal Danger
10
Contacts
11
The Story Terminator
12
With this issue, we’re pleased to announce that TCA volunteers are developing our newsletter. Gary and I welcome the assistance of our new core team, consisting of Marianne Diericks as project leader and Bruce Allen as proofreader. In addition, other volunteers will be contributing talents as needed, including Mary Courteau, Trish Johnson, Mary Montagne, and Marty Strong. We’re still looking for a volunteer with design and layout skills who would be willing to help with future issues. If you’re interested, please contact Dave Hanson.
Green Roofs By Sterling Malcomson
A recent trend for houses in the U.S. has been the installation of green roofs. Green roofs are completely
covered by vegetation and soil and have an impenetrable surface where the soil meets the house. Different types of grass and sedges can be planted on these roofs along with flowers and vegetables. If the roof is strong enough and the soil is deep enough shrubs and even small trees can be planted.
While the U.S. has a pretty small number of green roofs, Europe has many. In Germany, where the idea
of green roofs was invented in the 1960’s, an estimated 10 percent of homes have green roofs! The idea of
green roofs is becoming more and more popular in metropolitan areas and especially popular in Atlanta, Chicago, Portland, and Minneapolis. So what advantage does a green roof have over an ordinary shingle roof? Green roofs have many benefits that the common person may not know about. First off, green roofs re-
duce storm water runoff. Storm water runoff pollutes our local waterways and can cause severe erosion and flooding. Green roofs return about 75 percent of rainwater back to the atmosphere. They filter out metals
and pollutants that may be in the rainwater and return it clean. Another environmentally friendly advantage,
Green Roofs...cont. green roofs help eliminate CO2 from the atmosphere. CO2 is
the agent that causes our worldwide epidemic of global warming. Green roofs filter out this CO2 in exchange for oxygen.
For animal lovers, green roofs are the thing to have. With various types of vegetation on the green roof they promote
habitat for many kinds of birds and even some small mammals (if they are good climbers!). With wildlife habitat continually
decreasing in the urban setting green roofs help curb the probPhoto courtesy of Greenroofs.com
lem. If you don’t have enough room to plant a garden in your yard, green roofs provide ideal places for fruits, vegetables,
and flowers to grow in. It’s good to be environmentally friendly but what about the money involved?
Green roofs cost more to install initially, $15/sq. ft. compared to $4/sq. ft. for shingles, but in the end may actually save you money. They are better insulators than shingles and may
greatly reduce winter heating costs along with summer cooling costs. Over a ten-year period this may add up to a lot of money. According to a Penn State experiment, green roofs
on average last 2-3 times longer than regular roofs do. This in itself almost covers the difference in initial costs. With a green roof you wouldn’t need to spend money on the installation of
gutters like you would with a shingle roof. While some green Photo courtesy of Greenroofs.com
roofs may need some annual labor, others are self-maintaining. It just depends what you want out of your roof and how much you would like to spend.
For more information on green roofs…
As you can see, green roofs help with some serious envi-
“Green Roof”. 25 April 2007. http://en.wikipedia. org/wiki/Green_roof.
long run. While the United States is far behind Europe in the
Colwell, Dara. 2007. “Green roofs: Building for the Future”. Alternet. 1 May 2007 http://www.alternet.org/envirohealth/48530/ ?comments=view&cID=623576&pID=608600 Schloz-Barth, Katrin. 2001. “Green Roofs: Stormwater Management From the Top Down.” Environmental Design & Construction. January 15.
ronmental problems and will keep your wallet heavier in the number of green roofs, they are becoming more popular in
big cities. Green roofs not only benefit the homeowner but
also the delicate environment around metropolitan areas and worldwide. The next time you are thinking about installing a
new roof, think about the advantages of a green roof and the example you would be setting for others to follow.
Putting Down Roots - By Cliff Johnson Beauty in winter landscape may require planning The color contrast between summer and winter landscapes in Minnesota is amazing. Summer gardens
boast every color imaginable while winter landscapes are often drab and colorless. Snow, particularly in cities and along highways, takes on tones of gray as it collects dirt, then later reveals boring shades of brown as snow melts.
Over the past decade I have planted particular trees and shrubs that spice up the winter landscape with color and shapes. Some plants also attract wildlife that further enriches the nature panorama outside my windows.
Nancy Rose, a University of Minnesota extension educator in horticulture, lists various ways landscape
plants can provide winter interest: Colorful, persistent fruit adds cheerful ornamentation to trees and shrubs. Seed heads add texture and visual interest. Winter stems and bark provide bright colors, a rich metallic sheen, or the textural accent of papery curls. The branching pat-
terns of deciduous trees and shrubs are often interesting, particularly when branches are dusted with snow. And, of course, what would
the winter landscape be without the pleasing color and substance of evergreens?
A euonymus shrub (burning bush) growing a few feet from the
foundation on the south side of my house is loaded this winter with
tiny red berries. The plant has grown to about 10 feet tall so the berries nearly touch the south-facing windows.
A few feet beyond the euonymus, two crabapple trees have
Above: Euonymus atropurpurea
retained some of their fall crop of 1/2-inch apples, although blue jays
and cardinals have discovered the fruit and are gradually reducing the colorful crop as the winter progresses. Nancy Rose says that ‘Donald Wyman’ crabapple 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.
Just beyond my craAbove: Viburnum trilobum
bapple trees are a half
dozen American cranberry
bushes (Viburnum trilobum, also known as highbush cranberry) which bear clusters of fruit that start turning red in early fall and persist all winter. My father used to say that robins wait until
early spring for the fruit to soften, then gobble it up and get tipsy from eating the fermented berries.
Below: Viburnum lentago
Putting Down Roots...cont. More color is visible in this backyard area from the stems of dogwood
shrubs. I have both red- and yellow-twig dogwoods growing and the stem color gets more intense as winter transitions into spring. The dogwood
cultivar ‘Cardinal,’ a University of Minnesota introduction, is noted for having especially bright cherry red stems.
You’ll get more colorful stems on dogwood, according to Rose, if you
prune out some of the oldest stems each year -- this encourages more new stems which have the brightest winter color. One spring I planted 30
bare-root arborvitae (white ce-
dar) in a zigzag row about 100 Above: Juniperus virginiana
feet south of my house. These evergreen shrubs have grown
to nearly 10 feet in height and provide a pleasing contrast to the snow on the ground and the red berries on trees.
In previous columns I have written about landscape art -- my
arbors, trellises and birdhouses made from tree stems, branches and hollow logs. Each year I plant climbing pole beans on
a 12-ft. teepee trellis and then leave the vines attached during
winter. The vines collect snow and the structure offers a sculp-
Above: Cornus stolonifera
tural touch.
Two additional winter sculptures, one on either side of the pole beans, are 10-foot-tall clumps of “bamboo grass” (Miscanthus giganteus). This slow-spreading grass produced giant seed plumes this fall that reflect the sun and wave gracefully in the winter breeze.
Trees with shiny or curly bark can add winter interest. For shiny bark, Rose says that nothing beats Amur Below: Juniperus virginiana
chokecherry (Prunus maackii), a 15 to 25-foot-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.
Besides the arborvitae, I have planted white pine, Norway spruce, black hills spruce and white fir. The woody cones
borne by many evergreens and the blue, berry-like cones of certain junipers can add a decorative note to winter landscapes as well, Rose points out.
Putting Down Roots...cont. Rose suggests spending time studying 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.”
As I look out at my winter landscape, the plants and structures work together to create a pleasing view ex-
cept for the satellite dish installed to provide a high-speed Internet connection. I’ll just have to put up with this obstruction, however, since it gives limitless resource for researching more plants for my garden.
More than 200 previous Putting Down Roots columns can be viewed at Cliff Johnson’s website: www.puttingdownroots.net. The Master Gardener program is a part of the University of Minnesota Extension Service. For more information, or to ask a gardening question, call 952-442-4496.
Invasive Plants Should Go To The Landfill
DNR News May 8, 2007 Wisconsin Dept. of Natural Resources
Spring is the time when many property owners and volunteer organizations are hard at work trying to
eliminate invasive plants like garlic mustard from their woods, yards and local parks. Many invasive plants, like garlic mustard, continue to develop seeds once they have been pulled from the ground. For plants like
this, effective control means that the flowering plants must be removed from the site to keep the seed from
spreading. Allowing the plants to dry out and burning them is an option in some rural areas, but landowners should be aware that there are often restrictions or permit requirements for open air burning.
Although backyard composting is normally the preferred method for dealing with most yard waste, backyard compost piles and bins do not reliably generate enough heat for a long enough period of time to de-
stroy some plant seeds. The same problem may occur at many municipal or rural compost facilities, thereby spreading the invasive plants when the finished compost is utilized.
To ensure that the invasive plants are destroyed and the seeds not redistributed, the Department of Natural Resources Endangered Resources Program and Waste Management Program are asking property owners
to separate and bag any invasive plants in clear bags and label the bags “invasive plants – approved by WI
DNR for landfilling.” Groups removing invasive plants from public properties like parks should make arrangements with their local public works office for collection and disposal.
“Even though landfilling of yard waste is prohibited in WI, the DNR is using its enforcement discretion to
allow invasive plants to be landfilled because that represents the best available option for disposing of them,” said Cynthia Moore, DNR Recycling Team Leader.
“We don’t recommend composting invasive plants and their seeds because of the likelihood that
viable plants and seeds will be spread through the distribution of the finished compost. Only specially designed and carefully managed composting operations should accept invasive plants”.
Watching The “Pine” Tree Die! Elementary school children are so proud when they come home with that free
tree seedling plug. But, for unsuspecting parents the question quickly becomes:
“What do I do with this?” Not that a tree is time consuming like the classroom rat
or other rodents that need homes at the end of the school year. But, it still raises
questions like: “How big will the tree get?”, “Will it fit in my little yard?”, “Where will I plant this?”
For me, the solution seemed simple – let’s put this tree in a 5 gallon container in the garden until we figure out where in the yard it might fit. Unfortunately, 5 years later it was still in the container and it had insisted on growing.
Yes, it had become root-bound. And yes, saying “root-bound” was an underPlugs of Norway spruce seedling. Photo from: www.nurserymen.com
statement. The tree grew fine for several years, but recently a significant lean has developed. Additionally, over the last few years the insect problems have
been persisting and this spring is no different. These insects, secondary invad-
ers, often become the final straw bringing these trees to the brink and subsequent death.
Sawflies (Neodiprion species ) have been one of those insects this spring.
Populations are high and conifers that are heavily infested can be severely damaged. If infestations are left unchecked the newly de-
veloping foliage may not be enough to save the trees. Periods of drought also open the door to various
beetles - Turpentine beetles (Dendroctonus valens)
are another common secondary invader that can damage or stress these trees.
Bottom line, it is common for conifers to succumb to
secondary invasion after periods of stress and drought Sawfly Pin Sawflyon onRed red pine Photo: Dave Dave Hanson Photo: Hanson
has been a serious stressor in the last few years.
From the day these conifers are planted they are
“predisposed” to problems and under stress. Periods
Red turpentine beetle Red turpentine beetle pitch of drought, warm weather, salt and pollution all add to tubes. pitch tubes. Bob Oakes, Citation:USDA Bob Forthe issues that these pines face. The Twin Cities metro is the southern and west- I mage Oakes, USDA Forest est Service, forestryimern edge of the range for the eastern United States pines – Eastern white pine Service, forestryimages.org ages.org (Pinus strobus) and Norway pine (Pinus resinosa).
Watching The “Pine” Tree Die!...cont. At the left is the original range of red “Norway” pine in Minnesota and the southern most tip of this range is in the Metro Counties. Conifers tend to prefer a cool environment, plenty of moisture, yet well drained soils. Metro area landscapes
typically don’t provide these attributes; in fact they are typically hot and relatively dry sites with compacted soils.
There are several pines that are common in Minnesota landscapes including
native pines: Eastern White Pine (Pinus strobus), Norway or red pine (Pinus resinosa), and jack pine (Pinus banksiana).
Eastern white pine is a five needle pine and this trait easily sets it apart from the
other two native pines which have two needles per fascicle. The native two needle
pines, red pine and jack pine are easily distinguished by needle traits, cones and form. So let’s take a closer look at these two.
Jack pine has a twisted, divergent or “V” shaped
needle pair. Typically, the needle length on jack pine is ¾ to 1¾ inches long. This readily distinguishes
them from red pine which has needles that are typi-
cally 4-6 inches long, not divergent and not twisted. Red pine needles are described to break “cleanly”, not just fold over, when they are bent.
Conesand anddivergent divergent Cone needles of jack pine. needles of jack pine. Photo: Dave Hanson Photo: Dave Hanson
Just as distinguishing are the cones. Where jack
Mature cones on on red red pine.pine. Mature cones Photo: Dave Hanson Photo: Dave Hanson
pine has a cone that hugs or points to the end of the twig – red pine has pairs of
cones that are typically at right angles to the branch. Where jack pine cones have scales that often remain closed (serotinous), red pine has cone scales that open at maturity to release seed.
Finally, where jack pine is considered a medium sized, almost scruffy looking
tree, red pine is definitely in the large tree category and majestic is a term that is likely associated with red pine.
Unfortunately, this tree was doomed the day I moved it from the undersized
container to excessively drained Anoka sand plain soils. Fortunately, for me, it
is providing quite the study site. It is simply amazing what this tree tolerates and
survives; however, this is likely the last season since the root system is failing and the insects are happily feeding. Medium sized jack pine. Medium sized jack pine. Photo: Dave Hanson
Photo: Dave Hanson
Sawflies The Latest Buzz News In Urban Tree Problems
European Pine Sawfly
(A.K.A. some funny looking worms on your pine trees) By : Andrea Dierich (City of Andover Forestry Intern)
Is your pine tree looking a little bare? Does it appear to be a skeleton? Upon a closer look this spring you might have seen some type of worm on the needles. All throughout the City of Andover these pesky little lavae were wreaking havoc. So what was it? The European Pine Sawfly. Life Cycle:
(
As the name implies this pest was carried over on
wood shipments from Europe and has become estab-
lished in the United States. The female sawfly lays eggs in current year’s needle growth in the fall (figure 2),
which then proceeds to emerge in late-April to mid-May. The larvae are about .5-1 inch long with a small black head and a stripped back; two light green stripes, and Figure 1: Mature European Pine Sawfly Larvae
one dark green or black stripe on each side. The larvae, once emerged, feed on old needle growth moving
slowly, completely defoliating one branch before mov-
ing to another. This may not have seemed so slow this
year, since the high numbers of larvae did quite a bit of damage in a matter of days!
The larvae feed from mid-May through June and then begin to pupate in the soil beneath the trees or on the
Figure 2: Eggs inserted into the current needle growth
Control Methods During Larvae Stage*: Non-Chemical (CHEAP METHOD): - Handpick sawfly larvae off needles and branches, place in a sealed bucket or can (tedious but the most effective if the tree is short and infestation is smaller). - Mix a strong dish-soap with water and power-spray the tree, the soap will irritate the skin of the larvae promo ing susceptibility to pathogens and bacteria. Do this process a couple of times a week and continue to check for remaining sawflies. Chemicals (Read all directions before use to ensure the safety of pets and children that could be affected): - Horticultural oils, follow directions - Insecticidal soap, can be found at your local garden center - Or a spray with pyrethrin product, this chemical is made to kill larvae. *To prevent a break out this next year kill pupated larvae in needles and mix the duff layer underneath trees that were infected. In late April, look for emerging larvae and use one of the above methods if needed.
remaining needles of the trees in July and August. In
September and October they finally appear as wasp-like adults to mate and lay eggs before dying to complete their one-year life cycle. Why Now? Many insects go through boom and bust cycles. The relatively mild winter and the severe drought of this
spring created the right conditions for larvae emergence and prolific feeding.
Tips for Tree Survival Avoid further stress of severely defoliated trees.
Water your pines regularly throughout this summer, especially in droughty conditions, through the fall,
just before the first frost. Watch for other diseases or
insects on the remaining growth that could push a tree over the edge.
Sawflies cont. FAQ
Will my tree die?
A: No, your tree should still survive because the new growth is not being harmed. In some severe cases mor-
tality could be possible but unlikely. The defoliation will tend to set back or stunt the growth of the trees. Aid the
health of your tree and protect it from further stress, which could result in death, follow the aforementioned tips. Will this be a problem next year?
A: If we have another mild winter and droughty spring it is more than likely that this will reoccur. Prepare by
looking over current year’s needle growth in early April and pruning or using an insecticide to prevent hatching and feeding. Continue to check pines through April into May and take corrective action as soon as signs appear of larvae infestation.
Will the needles eaten, re-grow?
A: No, once a needle is cast or shed from the branch it will not re-grow a new needle in the spot. The only new growth that will occur is at the tips of branches or where a new bud appears. Your pine might look a little bare for a year or two until it recovers from the defoliation of this year.
For More Information: Search the U of MN IMP Website: (http://www.entomology.umn.edu/cues/Web/128EuropeanPineSawfly.pdf) or visit the City of Andover Website, under City Departments, then Natural Resources: (http://www.ci.andover.mn.us/) Special Thanks to: Professor Gary Johnson, U of MN and Sue Burks, MNDNR Plant Pathologist. Photo Credits: Figure 1: www.pfc.forestry.ca/.../european_pine_e.html Figure 2: www.plantpath.cornell.edu/trees/EuroPsawf.html
State’s Ash Trees Face Mortal Danger By Bill McAuliffe Star Tribune May 24, 2007
Hoping to keep a destructive insect at bay, DNR officials won’t allow campers to bring firewood into state parks or other recreational areas.
With the upcoming holiday weekend likely to send thousands into Minnesota’s woods, state officials are
enlisting campers in the fight against the emerald ash borer, a bug that has killed 20 million ash trees in the Midwest.
Campers won’t be allowed to bring firewood into state parks and other state lands, and the state Department of Agriculture will put up billboards along highways to warn motorists against transporting firewood.
“Pack marshmallows, not firewood,” the billboards will say. The Ag Department has also established an informational website, www.saveourash.net.
The aim is to forestall the westward advance of the ash borer, an invasive pest without serious natural
predators that has killed 20 million ash trees in the lower Midwest and southern Ontario since it was discovered near Detroit five years ago.
Regarded as potentially more destructive than the elm bark beetle, the emerald ash borer destroys every type of ash in its way.
Ash makes up 7 percent of all trees in Minnesota and 10 percent of all hardwoods. “The simple message is: ‘Don’t bring firewood from home,’ “ said Chuck Kartak, deputy director of the Department of Natural Resources division of parks and recreation.
Campers in state parks and on other state lands who bring wood with them will be asked to exchange it on site. Next year, they’ll face a $100 fine.
The state will burn the wood to ensure that it’s destroyed. Though the new restrictions don’t affect campers in private campgrounds, people at cabins or even hom-
eowners, officials are hoping that the message spreads. The Agriculture Department is also posting informational signs on ash trees in the Minneapolis Chain of Lakes area, around the State Capitol and in Duluth and Rochester, extending a similar effort underway in eight other states.
The department is also certifying firewood sellers whose wood has been harvested within Minnesota. The bug hasn’t been found yet in Wisconsin or Minnesota. Left to travel on its own six legs, it likely
wouldn’t arrive here for decades, but authorities are concerned that it might hitch a ride on infected firewood traveling from quarantined states -- Illinois, Michigan, Indiana, Ohio and Maryland.
Ash has some commercial uses, but authorities are focusing their attack now on firewood because its distribution is informal and hard to monitor, said Mike Schommer, state Agriculture Department spokesman.
State’s Ash Trees Face Mortal Danger...cont. Ag Department researchers have developed about 100 “trap” trees around the state in recent years in an
effort to find emerald ash borers, and found none. They plan to expand the effort to about 1,000 trees along major transportation routes this year.
Despite all those preventive and monitoring measures, officials still fear the ash borer’s determination. Val Cervenka, forest entomologist for the DNR, said she regards its arrival in Minnesota as “inevitable.” At a news conference, Cervenka and others said they hope the firewood restrictions and other measures buy enough time for scientists and foresters to develop effective weapons against the ash borer.
Contact Phone Numbers
Program Contacts:
Gary Johnson - 612.625.3765 or grjohnson@umn.edu
Contacts: Regional Extension Educators:
Dave Hanson - 612.624.1226 or dlhanson@umn.edu
Bob Murgaas - 651.480.7706
Mailing Address: 115 Green Hall 1530 Cleveland Ave. North St. Paul, MN 55108
Gary Wyatt - 507.389.8325 or wyatt@umn.edu
County Contacts:
Patrick Weicherding - 763.767.3836 weich002@umn.edu
Additional Reference Contacts:
Carver County(Jackie Smith) - 952.466.5309 smith515@umn.edu
Debby Newman (Info-U) - 651.624.3263
Olstead County - 507.285.8250
Ken Holman (DNR Forestry) - 651.296.9110 ken.holman.@dnr.state.mn.us
Dakota County (Barb Stendahl) - 952.463.8002 stend004@umn.edu Ramsey County - 651.777.8156
Scott County (Jackie Smith) - 952.492.5410 smith515@umn.edu St. Louis County (Bob Olen) - 218.726.7512
Don Mueller (DNR Forestry) - 651.772.6148 don.mueller@dnr.state.mn.us
Paul Walvatne (MNDOT) - 651.296.284.3793 Paul.Walvatne@dot.state.mn.us Great River Greening - 651.665.9500 Tree Trust - 651.644.5800
Story Terminator
Above: Picea mariana Photos taken by Dave Hanson
  In the last month the conifers in Minnesota have
been growing out the new ovulate (female) cones.
The photos included here show the ovulate cones of the spruces from early May.
  Check the pictures online - most of the conifer cones are a rich magenta (reddish purple) when
first emerging. Picea abies - Norway spruce, Picea
glauca - white spruce, Picea marianna - black spruce, and the non-natives Picea pungens - Colorado blue
Above: Picea abies Photos taken by Dave Hanson
spruce, Picea omorika - Serbian spruce.
Left: Picea glauca Below: Picea pungens Right: Picea omorika Photos taken by Dave Hanson