Listen up please! I so rarely get to write something important!
Big news just rolled out of the University of Minnesota. After checking over 500 potted trees randomly selected from wholesale and retail nursery yards, University researchers discovered a great many that were potted too deep, with, on average, six to eight inches of soil packed above the first set of lateral roots (or "shoulder" roots). The same situation has been found in trees dug and sold with the root ball wrapped in burlap.
If homeowners plant a tree at the same level as the soil in the pot,
but don't check to see if excess dirt became packed over the top of the
shoulder roots when the tree was dug and prepared for sale, they could
be planting the tree too deep. Planting a tree even six inches too deep
can cause root girdling, as the roots, sensing they're too far below the
surface, tend to grow up, then in, circling the trunk. The tree either
will die in five years, go down in a storm in twenty, or live but disappoint.
At the nursery, scrape away the soil around the trunks of trees sold in
containers, and be certain you find the start of the shoulder roots immediately.
Bring along a straight piece of coat hanger wire when choosing ball-and-burlap
trees. Plunge the wire through the burlap next to and parallel with the
trunk of the plant. If you don't hit shoulder roots immediately, the plant
was not dug and wrapped properly. If you wind up purchasing a tree with
excess soil packed over the shoulder roots, remove all of it, then plant
the tree so that the shoulder roots are just barely beneath the surface.
It all came back to me. Last year we were shooting an HGTV deal on planting a tree, and the potted tree the production crew brought for me to plant, a ten-foot Maple, had exactly six inches of excess dirt on top of the roots that I had to remove before taping the episode.
How widespread is this problem? Assume that it's nationwide, and assume it's been going on for years. The State of Minnesota runs a pretty tight ship when it comes to nursery industry knowledge and professionalism, Department of Agriculture supervision, University of Minnesota testing, research, and the like. So if it happened here it could well be a problem in your state or country. Some of the trees found at fault in the study were Minnesota-raised and some were from out of state. If you find one, don't read the riot act to your local retail nursery; most often it was dug improperly at the wholesale level. Be on your toes.
Best Strategies for Dealing with Brown Evergreens
It
was a bad year for winter-burn, no question about it. Even established
trees and shrubs that one could only assume were well past risk have suddenly
entered April in the north showing brown-tipped needles, and in some cases,
entire branches.
Take heart. It may not be as bad as it looks. From the combined research and knowledge of horticulturists at the University of Minnesota, here is what to do if you fear portions of your evergreens have turned everbrown:
1.
Wait and See
Though needles and branches may have turned brown, the branches may not be dead
(the needles unquestionably are). Don’t prune anything yet. The branches
may bud and produce sub-branches with new needles that will get the tree
or shrub looking decent by mid-summer.
2.
Water
Start watering, though. The ground has thawed in Zone 4 and, I would assume,
Zone 3, so if your soil will take water, go for it. You need to introduce
moisture into the equation as soon as possible. Might I suggest that part
of the problem lies in not watering evergreens sufficiently last fall?
3.
Mist
Get moisture onto the evergreen, with a misting nozzle if you own one, or a
plain old spray attachment if you don’t. Spray the whole plant every day,
particularly during sunny days.
4.
Fertilize
Get some granular evergreen fertilizer into the ground around the plant right
now. You want it there the moment the roots kick in.
You’ll learn what you need to learn by about the first of June. If the entire tree has turned brown (or orange), you will probably wind up giving it the Ultimate Prune, but until then, keep the faith. Evergreens have been around a lot longer than we have, and you may be thankfully surprised.
As season hits high gear, U of MN's online
newsletter keeps gardeners current
Check out Yard and Garden Line News, a free online newsletter for gardeners,
on the World Wide Web. Each issue features timely information on lawn
and garden care, current insect pests and plant diseases. The twice-monthly
newsletter is written by University of Minnesota Extension Service experts
in horticulture, plant pathology, entomology and forestry. A new issue
is posted on the Extension Service's web site on the first and 15th of
each month throughout the growing season. Look for it at www.extension.umn.edu/yardandgarden.
Scroll to the bottom and click on Yard
& Garden Line News.
Each issue features color photos and short seasonal articles pertinent to current conditions around the state, making for a good guide to activities in your Zones 2-4. The current May 15 issue, for example, includes a great article by Deb Brown on creating colorful scenes with annuals, some common sense herbicide guidelines, an update on mosquito control, and the skinny on worms falling from elm trees, to name just a few.
From those frigid, friendly foresters at the University of Minnesota's
School of Horticultural Sciences, here's a new list of trees available
from nurseries throughout Zone 4 that are proving to be less than adequate
for the task at hand. Avoid the following:
Catalpa
Northern catalpa [C. speciosa]
Hardiness limitations. Consider it Zone 5.
Corktree
Amur corktree [Phellodendron amurense]
Hardiness limitations. Consider it Zone 5.
Crabapple
Siberian crabapple [Malus baccata Jackii]
A magnet for rabbits. Select only if providing complete winter protection
from our furry, hasenpfeffer-inspiring friends.
Elm
Lincoln elm [Ulmus pumila x U. rubra 'Lincoln']
Hybrid selection from a cross between Siberian elm and red elm that has
apparent resistance to Dutch Elm Disease (DED) but has not been widely
tested. Subject to severe defoliation by the elm leaf beetle.
Red (Slippery) elm [U. rubra]
Species native to Zone 4, but susceptible to DED.
Regal elm [U. carpinifolia 'Regal']
A DED resistant elm that is subject to severe defoliation by the elm leaf
beetle. Use should be restricted to the southernmost edges of Zone 4
Rock elm [U. thomasii]
Native to Zone 4, but susceptible to DED.
Sapporo Autumn Gold elm [U. carpinifolia 'Sapporo Autumn Gold']
A DED resistant elm that is subject to severe defoliation by the elm leaf
beetle.
Siberian elm [U. pumila]
Widely planted as shelterbelt or windbreak tree that is resistant to DED
but is subject to winter injury and defoliation by the elm leaf beetle.
This tree is not suitable for urban plantings.
Hawthorn
Downy hawthorn [Crataegus mollis]
Very susceptible to rust and fire blight.
Washington hawthorn [C. phaenopyrum]
Very susceptible to fire blight. Markedly less susceptible to rust than
many other hawthorns. Cold hardiness limits the use of this species to
the southernmost portions of Zone 4.
Note: Hawthorns may need winter protection from rabbits and are sensitive to deicing salt spray and run-off.
Honeylocust
Thornless honeylocust [Gleditsia triacanthos var. inermis]
Zone 4 hardiness and Nectria cankers are concerns. Cultivars include 'Halka',
Imperial, 'Moraine', 'Shademaster', Skyline, Summer Lace, and Sunburst.
Magnolia
Cucumbertree magnolia [Magnolia acuminata]
Plant in protected locations, winter hardiness may be an issue.
 |
| Acer x fremanii (Freeman Maple) |
Maple
[Acer x fremanii]
Existing cultivars have performed poorly due to an apparent lack of hardiness.
Freeman maples should be used with caution in Zone 4.
Norway maple [A. platanoides]
Winter hardiness and susceptibility to Eutypella canker limit the usefulness
of this species and its cultivars in Zone 4.
Note: Maples other than Norway maple are sensitive to deicing salt. Maples perform better in lawn or park settings and in groups, rather than as single specimens in fully exposed boulevards. Planting with the root collar at ground line is important to see and treat girdling root syndrome.
Oak
Eastern pin oak [Quercus palustris]
Intolerance to alkaline soils and marginal winter hardiness limit the
usefulness of eastern pin oak within much of Zone 4.
Plum
Canadian plum [Prunus nigra]
A small tree with white flowers in the early spring. 'Princess Kay' is
a double-flowered cultivar that was collected from Itasca County and introduced
by the University of Minnesota Landscape Arboretum. This species is very
susceptible to black knot. Needs winter protection from rabbits.
Poplar
Lombardy poplar [Populus nigra 'Italica']
Lombardy poplar is an upright, fast-growing cultivar that is often used
in windbreak and shelterbelt plantings. It is extremely susceptible to
several canker diseases and as a consequence is short lived.
All poplars have shallow and aggressive roots. Do not plant near pavement
where shallow roots can cause damage.
Class dismissed!
Blueberries
— one of life's great pleasures, and a fruit I've been growing for
six years. The University of Minnesota has been instrumental in creating
and bringing to market high-yield blueberry bushes hardy to Zone 3.
In case you missed it, the University's Web publication, Yard & Garden Lines News, recently carried a great article by Jim Luby, Fruit Crops Breeder, on breeding history plus how to select and grow blueberries in the north. If interested, click on the link below.
Blueberries are quite easy to grow and besides being a fruit-producer are an attractive ornamental shrub in their own right. In fact, in full sun, they prune into a nice hedge.
Before you try growing blueberries, however, be forewarned about the cruelty of the addiction: It's a tough, bitter day at the RG household the first morning in late July when I face my breakfast cereal aware of the fact that my garden's fresh blueberry season has ended!
When
I was a student at the University of Minnesota in the '70s, the St. Paul
horticultural campus existed, I'm pretty sure, though I never had cause
to set foot there. The only reason to tread those hallowed fields was
if your idea of a good time was juggling entomology, soil science, and
advanced biology en route to a degree in Golf Course Turf Management with
a minor in sheep farming.
No
one convinced me otherwise, since my crowd never ran across any of the
St. Paul "farm kids" drinking at sorority parties, dining at
Mama D's, or debating William Burroughs late at night in the smoky bars
of 7 Corners. Denizens of the St. Paul campus collapsed in their bunks
right after supper, we assumed, then arose early, to do their chores before
class.
Twenty years later, when I was no longer an idiot, I realized the St. Paul campus is where I should have been taking classes all along, assuming the University of Minnesota's internationally renowned College of Agricultural, Food, and Environmental Sciences would have taken me. Ah well. Youth is wasted on the young.
I'm reminded of my college days because 2001 marks the 150th anniversary of the University of Minnesota. And what you'll find of great interest is that the University has just published a wonderful booklet commemorating the incredible number of hardy plants researchers at the U have introduced to gardeners across the globe over the past many decades.
Cherries, apricots, pears, plums — thanks to the University of Minnesota, you can grow these in the north. Hardy varieties of apples, of course, have been a mainstay of University research ever since the 1920 introduction of the Haralson.
Thanks in part to the U you can also grow many dependable smaller fruits, such as blueberries, raspberries, strawberries, gooseberries, and currants (the Red Lake currant, introduced by the U in 1933, is probably the most popular current grown around the world).
In total, it's an incredible list. Ornamental trees, shrubs, chrysanthemums, vegetables, grapes, azaleas, we're talking hundreds of plants made healthy, made hardy, and made here in Minnesota.
Click to the link below to order the booklet, or to view it on-line.
One warning: Have some time on your hands.
http://www.extension.umn.edu/distribution/horticulture/DG7564.html
Creating a Low Maintenance Lawn
About the only thing I remember from the seemingly endless Lawn and Turf Management course I took at the University of Minnesota was how warm the room was. The instructor was teaching all of us aspiring Master Gardeners how to grow and maintain a perfect lawn, and if not for the female bartender from Owatonna in the fourth row I do believe I would today be mad.
But
my head did jerk front, center and to the instructor when he begrudgingly
swung into a brief dissertation on low-input lawn care. This practice
is designed to minimize the amount of chemicals and, even more important,
time and energy required by homeowners possessing the chthonic will to
cast their lot with the Green Plague.
It involves conversion – from the high energy, high input, greedy, demanding, scurrilous, petulant crop of Kentucky Blue grass we inherit when we purchase a home, to new, ultra low maintenance grass mixes. You don't pull out the sprinkler during dry periods (at least I don't), you never fertilize, the stuff doesn't grow very fast, yet your lawn stays green and weed-free enough that your neighbors don't report you to the local authorities. That's right, there is an alternative for those who, like me, consider caring for a lawn the gardening equivalent to cleaning the toilet.
The University of Minnesota is a leader in study of low input lawn care (they've dubbed the topic "LILaC," for Low Input Lawn … well, you get it), and has just released an update on the topic, including some new information and findings.
To quote my buddy, the sweet and saucy Deb Brown, U of M Extension Horticulturist, from her paper, "Several new low maintenance lawn mixes were planted, then monitored for three years in research plots at the Minnesota Landscape Arboretum and at the Waseca branch of the University's Agricultural Experiment Station. While no one would mistake the results for a highly maintained golf course or finely manicured lawn, some were considered 'acceptable' by the crew of Extension personnel and Master Gardeners who evaluated them monthly throughout each growing season."
Deb probably couldn't resist placing parentheses around the word acceptable, since she understands the Turf Nuts at the University were simply damning with faint praise. (You have to realize, these guys have devoted their lives to studying GRASS.) I think she'd agree the correct way to read this is that it's GREAT NEWS for any homeowner interested in seeing the pursuit of creating and caring for The American Lawn relegated into the same job bin that houses cleaning the gutters, shoveling the walk, and staining the deck.
Interested? I've been practicing LILaC for years, and my lawn typically looks cleaner and remains greener than the high-priced spreads on my block. Here's a link to Deb's paper on the University's Extension Services Web site, plus a list of nurseries that can get you started with seed: http://www.extension.umn.edu/projects/yardandgarden/ygbriefs/h325lawn-lowmaint.html
Seed sources for low maintenance lawn mixes
Prairie Nursery
P.O. Box 306
Westfield, WI 53964
www.prairienursery.com
What's in it: six different fescues. (Best to use this one if your neighbors
are persnickety)
Dryland Ecology Lawn Mix
Nichols Garden Nursery
1190 North Pacific Highway
Albany, OR 97321-4580
www.nicholsgardennursery.com
What's in it: perennial ryegrass and fine fescue with some flowers and
clover
Fleur de Lawn
Hobbs and Hopkins, Ltd.
1712 SE Ankeny
Portland, OR 97214
What's in it: mostly perennial ryegrass with some flowers and clover
New at the U will be updated Sept. 15
New at the U Archive