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Showing posts from 2009

Cool Plants for the Holidays

Carl Hoffman, University of Minnesota Extension Horticulturist

Be it reasons relating to the economy, an elevated environmental consciousness, or merely a reason to wear a new Snuggie™, we are lowering the temperature in our homes. We can easily compensate for the cool temperatures, but what about our plants?

As we enter the holiday season, many of us plant lovers like to use blooming plants to brighten and add seasonal cheer to the interior of our homes. Nearly all of the holiday favorites will perform well for a while, but then will begin to languish.

We are fortunate, however, that there are some blooming holiday plants that actually thrive in cool, or even cold, temperatures. Generally, temperatures above freezing, but below 50° F are considered cold, and temperatures between 50° F and 65° F are considered cool. Even some plants, like the poinsettia that prefer warmer temperatures will do quite well in a cooler environment if they are kept from cold drafts and are not overwatered…

Falling Leaves Reveal Unsightly and Mysterious Galls

Michelle Grabowski, University of Minnesota Extension Educator


As leaves are lost this fall, some gardeners are noticing unsightly lumps and bumps on the bare branches of their trees. A variety of causes, both living and non living, can result in irregular tree growth. However if round rough balls of wood are clustered on the trunk, branches, and twigs of the tree this is likely phomopsis gall. Phomopsis gall is a fungal disease caused by several species of Phomopsis. In Minnesota, Phomopsis galls are most commonly seen on Hickory (Carya spp.) and Maple (Acer spp.) trees. This disease can also infect American elm (Ulmus americana), several species of oak (Quercus spp.), Viburnum spp., Forsythia sp., rhododendrons and azaleas (Rhododendron spp.).
Phomopsis galls are spherical wood balls growing on tree trunks or branches. Galls may be as small as a pea or up to 10 inches in diameter. In most trees, the galls look like a cluster of small nodules or bumps, all pushed together into one l…

An Un-Ordinary Growing Season for All-American Selections at the MN Landscape Arboretum

Redistributed with permission from Arboretum News, Dec./Jan. issue
Ted Pew, Landscape Gardener, University of Minnesota Landscape Arboretum


The All-America Selections gardens this year at the Minnesota Landscape Arboretum were a mix of strange and stranger. For starters was the weather. Snowfall last year was low with minimal moisture content. The growing season--the end of May to the end of July--was cooler than normal. August was a bucket load of moisture but summer came in September with 80 degree temperatures and dry conditions. The 2010 AAS winners featured flowers only. The strange factor about the AAS was the expected colors on certain annuals. We had three outstanding cultivars for the 2010 sneak peek despite four plant diseases in the AAS bed and a crop failure.

Twinney Peach Snapdragon, aptly named for its color, had a double flower form with soft shades of peach, yellow and light orange color tones. This cultivar was quite floriferous--blooming early and up to frost--with a …

Cottony Grass Scale: A Year Later

Bob Mugaas, University of Minnesota Extension Educator

Jeffrey Hahn, Asst. Extension Entomologist



This past year saw a significant increase in the number of reported cases of cottony grass scale (CGS), Eriopeltis festucae, in Minnesota lawns. In 2007, we were only aware of one reported case of cottony grass scale. By 2008, that number had grown to about 6 newly reported cases with the one from 2007 disappearing entirely as there were no signs of infestation in 2008. However, by the end of September in 2009 the number of reported cases that we knew about rose sharply to between 75 and 100. While these were reported cases and not necessarily confirmed infestations, most recognized and described the symptoms, and ultimately the insect, as that shown in our previous article first describing this insect in Minnesota. (See the December 2008 YnG newsletter). Hence, it appears reasonable to assume that most identifications were likely correct.
In order to get a better feel for the scope …

December 2009 Garden Calendar

Karen Jeannette, Yard and Garden News Editor
Including excerpts from the 2009 Minnesota Gardening Calendar


It's not too late to protect your plants from Minnesota winter sunscald, animals, salt, snow, ice, and winter discoloration.  See: Protecting Trees and Shrubs Against Winter Damage
Mulch when the ground is frozen to keep the ground frozen, by applying a 4 - 6 inch layer of mulch (i.e. clean straw or leaves) over perennials or at the base of trees and shrubs.  Mulching to keep the ground frozen will help prevent those soil freeze-thaw cycles that can cause damage to roots and heaving of new plantings and perennials above the soil line.

Need to review which trees to select for Christmas?  See Kathy Zuzek's December 2008 article: It's Time for the Christmas Tree

Is your yard or garden ho-hum this time of year? Get inspired with Plants for Winter Interest  or visit your favorite full-size evergreens at the Minnesota Landscape Arboretum's arborvitae, pine, spruce, and

An Interesting Insect Found In a Home Yard

Jeffrey Hahn, University of Minnesota Asst. Extension Entomologist

An unusual insect, a northern mole cricket (Neocurtilla hexadactyla), was submitted to the entomology department in August. This insect was found by a homeowner in their yard in North Branch (Chisago county) in east central Minnesota. Northern mole crickets are found throughout the eastern U.S. in low lying moist areas, e.g. along the margins of lakes and streams. They are rarely found in home lawns and are not considered to be a pest in Minnesota.

This brown insect grows up to 1 1/4 - 1 1/3 inches long, has moderate length antennae and short wings that only extend about half way down its abdomen. What is particularly distinctive about this insect is its stout, mole-like front pair of legs which are modified for digging (called fossorial). They have four dactyls (claws) on their tibia which distinguishes them from closely related mole crickets. Despite their ungainly appearance, northern moles crickets are capab…

Fungi Sprouting on Trees Have a Scary Story to Tell

Michelle Grabowski, University of Minnesota Extension Educator


Photo 1 (left): Basidocarp of Climacodon septenrionalis. Michelle Grabowski. With October's frequent rain, many gardeners have noticed fungi sprouting from some landscape trees. These fungi may be any number of shapes, sizes and colors. They may arise from the trunk itself, from the root flare of the tree or from the roots. In all cases, fungi growing directly on a live tree tell the tale of heart rot within.

What's in the Trunk?
In order to understand heart rot, gardeners must understand a little bit about the wood within a tree trunk. Trees can have several different kinds of wood within their trunk. Sapwood is composed of living cells with a number of jobs to do. Sapwood cells conduct sap through the tree, store extra energy, close off wounds, and actively fight invading microorganism. In all trees, sapwood occurs in the outer most rings of the tree. Some trees, like maple, birch, beech and poplar form only sap…

Dormant Seeding Lawns: Last chore of the season?

Bob Mugaas, University of Minnesota Extension Educator


Photo 1 (above): Thin lawn area that could benefit from dormant seeding. Bob Mugaas.
One last shot at lawn improvement can be done even yet this fall. By early November, most lawn care chores and activities are completed; lawn mowers are put away, watering has ended, hoses are drained and stored for the winter, irrigation systems have been blown out and winterized and, the last, late season nitrogen fertilizer has been put down.  Yet, there remains one activity that can still be done to help repair or thicken the lawn for next year. In fact, prior to the early part of November (at least in the Twin Cities area, earlier in the northern half of Minnesota), it would be have been too early to do this task. That task is known as dormant seeding.  It is best employed when wanting to reseed bare soil areas or help thicken up thin lawns. It is not as effective, where lawns are thick and dense with little opportunity to achieve the good…

Edible Landscape Wrap-Up

Emily Tepe, University of Minnesota Research Fellow, Department of Horticultural Science

After many weeks of harvesting mountains of chard, tomatoes, zucchini, peppers, cucumbers, raspberries and a multitude of other vegetables, fruits and herbs, the University of Minnesota Edible Landscape has been put to bed. Well...almost. The few lone stands of silvery blue kale seem to mock the cold, their leathery leaves sweetening with each frosty night. And many of the herbs are even holding onto their green. Other than those, the Edible Landscape is now resting after a long and productive season.
Photo 1 (left and above): Snow on dinosaur kale in the University of Minnesota Edible Landscape on October 12, 2009. Emily Tepe.
If you haven't had a chance to see the gardens on the St. Paul campus this year, and if you haven't been following the Edible Landscape blog, here's a rundown of some of the details of the project. The Edible Landscape filled four beds outside the Plant Growth …

Field Guides Can Be Fun

Jeff Gillman, Nursery Management Specialist



Different people collect different things. Some like baseball cards, some like shoes, and some like coins. I like books about insects. No, really, I do. Just glancing up from my desk I can count something like 5 field guides, 10 general entomology texts, and a slew of others that fit into categories like insect control, insect taxonomy and insect physiology (I have a lot more at home). If you were to spend some time with these books you would discover rather quickly that, all in all, entomologists are boring writers. No zip, little spark. And that, in a nutshell, is why I like Jeff Hahn's new book Insects of the North Woods so much.

Photo and Cover: Insects of the North Woods, by Jeffrey Hahn. © Kollath-Stensaas Publishing.

Just looking at the cover of Insects of the North Woods you might be convinced that this is just a typical insect field guide. It's got some pretty pictures and, on the back, the obligatory author photo. But when …

What's Up With That?!

Birch Abnormal Growth Syndrome (BAGS) aka. Mouse Ear DisorderCarl Rosen, Extension Soil Scientist and Karl Foord, Extension Educator


The strange leaf symptoms on this river birch tree, taken on August 7 (Photo 1, left) were diagnosed as birch abnormal growth syndrome or BAGS. New leaves are severely stunted and take on a mouse ear appearance. For many years the cause of this disorder was a mystery, but it is now known to be due to a deficiency of nickel.

Photo 1 (left): River Birch 'Summer Cascade' at planting time showing symptoms of nickel deficiency (BAGS). Photo taken August 7, Karl Foord.

Nickel is an element only recently shown to be essential for plant growth and is required in very small amounts. Almost all soils have enough nickel to support plant growth, but under some conditions, nickel deficiency can still occur. The mouse ear symptoms on this river birch were first seen when growing in a peat-based container mix, and were initially misdiagnosed as bud damage fr…