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Friday, January 1, 2010

Planning the 2010 Garden with Minnesota Gardening Information

Karen Jeannette, Horticulture Research Fellow & Yard and Garden Editor

2009-2010 gardenplanning.jpg
What are your gardening plans for 2010?
Karen Jeannette

For many gardeners, the gardening season starts as soon as garden catalogs arrive and seed packets are back on the shelves of garden centers and nurseries. At this time of year, it's tempting to choose the flower varieties that most quickly jump off the page of gardening catalogs with the newest improved colors, or to select vegetables packets with photographs of the most succulent varieties you've ever seen. While sometimes those varieties are in fact winners, Minnesota growing conditions can challenge the best of the best nationally rated varieties, not to mention those that are just the best photographed.

Finding a stunning specimen or exceptional deal on a plant is always a thrill.  However, when trying to get the best value from your plants in 2010, don't forget that finding the right plant for its growing conditions can create much value through benefits such as improved growth, insect and disease resistance, and fewer maintenance needs.

Choosing varieties to grow for the coming gardening season is a common garden task for many in January. Yet for some, formulating overall landscape plans to meet site conditions and functional goals must come first.  Among hundreds of resources at the University of Minnesota Gardening Information website ( ), here are a few highlighted resources to start gardening with for 2010.
  •  U of MN Annual Flower Trial 2009 - Find the 2009 Annual Flower Trial's top performing annual flower cultivars that are likely to be seen on the market in 2010 or shortly after.
  • Starting Seeds Indoors - A guide to growing plants from seeds, including tips for buying seed and supplies, planting, and how to successfully grow seedlings for transplanting into the garden at the right time.
  • The Best Plants For 30 Tough Sites - Trying to find out which plants are deer resistant, what grows in dry shade, or which annuals are more cold tolerant than others? University of Minnesota Extension Service Master Gardeners draw on their 30 + years of teaching and experience to provide this list of plant selections for 30 tough sites.
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    Enjoy the bounty by choosing
    Minnesota hardy fruit varieties
    Karen Jeannette
  • Landscaping - January is a great time to formulate landscape plans. The landscaping section of garden information provides many resources to help you get started.
  • Use Diagnostics and Wildlife for troubleshooting last year's plant problems so you can formulate appropriate plans and prevention strategies for 2010.

Find More Minnesota General Gardening Information by Topic

Go to:
  • University of Minnesota Gardening Information website @

  • Find the plant topic your interested in the left-hand column under the "Find information on" heading

  • Seek out the general information sections about the topic to learn more

Screenshot (below): Finding general plant information by plant topic @

U of M_ Gardening Information_ Information - Vegetables-2-2-1_Medium.jpg

The Fingerprint of a Virus

Michelle Grabowski, University of Minnesota Extension Educator
Cyclamen are popular plants to brighten the home during the winter months. Flowers come in multiple shades of pink, red, lavender and white. When the blooms are spent cyclamen have interesting white patterns on their leaves, varying from an almost complete white horseshoe to regularly spaced white blotches depending on the cultivar. These leaf patterns are normal for cyclamen and make them an interesting foliage plant.
INSV 2 K.Snover-Clift NPDN.jpg
INSV symptoms on cyclamen
K. Snover-Clift, NPDN

Patterns that indicate a problem
Gardeners should beware, however, of leaf patterns that occur on some leaves but not others. The natural white color patterns on cyclamen leaves should be fairly consistent on all of the plant's leaves. If you are noticing unusual color patterns on some leaves but not others, this may be a symptom of a common viral infection.

Cyclamen are one of many hosts to the plant virus Impatiens Necrotic Spot Virus (INSV). This virus was first discovered on impatiens plants showing dark colored ring spots on its leaves. Since then it has been discovered that INSV can infect over 300 species of plants. Many flowering house plants, annuals, vegetables and even weeds can be infected with INSV.

The symptoms of INSV vary from plant to plant and even between cultivars. Some plants have random brown dead spots on leaves or streaks on stems. Others are stunted, wilt and die. Many have ring spots on leaves. Cyclamen infected with INSV have random brown spots, often with one or more brown rings around them. In many cases, multiple yellow to brown rings form on infected leaves, looking almost like a fingerprint. These types of ring spots are characteristic of viral infection.

How did my plant get infected?
INSV K.Snover-Clift NPDN.jpg
INSV symptoms on cyclamen
K. Snover-Clift, NPDN

INSV is transferred from plant to plant by western flower thrips (Frankliniella occidentalis), a common insect pest found in greenhouses. Thrips larvae that feed on an INSV infected plant pick up the virus. The virus survives within the thrips and the adult thrips are able to transmit the virus to any plant that they feed on for 5-10 minutes. Once infected with INSV, thrips carry the virus with them for the rest of their lives. Infected house plants could have been infected at the time of purchase or thrips carrying the INSV virus could have been brought into the house on the cyclamen or other plant.

What can I do about INSV?

Unfortunately plants infected with INSV can never be cured. They will carry the virus with them for the rest of their lives and can pass it to other plants if western flower thrips are present. Therefore it is best to destroy infected plants to prevent the spread of the disease. Plants infected with INSV can be thrown into the compost pile because the virus will not survive without a live host plant. If thrips are a problem on this or other houseplants, steps should be taken to control them. Many cultural and chemical control strategies are available to manage thrips and can be learned by reading the UMN extension publication 'House Plant Insect Control'. Remember, only thrips that have fed on an INSV infected plants will be able to transmit the virus, so the presence of thrips alone does not mean that plants are infected with INSV.

The best management strategy is to avoid bringing home plants that are infected with INSV or western flower thrips. Before purchasing a cyclamen, inspect both the upper and lower surface of the leaves for unusual yellow to brown spots, especially ring spots. Thrips may be difficult to see without a hand lens since they are only 1/16th of an inch long and very thin. Tapping the leaves of a plant over a white piece of paper can knock off some insects that you will then be able to see moving across the sheet.

Unfortunately plants recently infected with INSV may not show symptoms for a week up to a month. It is therefore possible to purchase a healthy looking infected plant. To avoid future problems, keep the new plant separate from other plants in the house for about 2-3 weeks. This will allow time for symptoms of the virus or thrips feeding to develop without allowing the problem to spread to other house plants.

For more information about general cyclamen care, read the UMN extension publication 'Cyclamen care'.

That Is One Big Caterpillar

Jeffrey Hahn, Asst. Extension Entomologist

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Ficus sphinx caterpillar
Janet Moe

In early December, a Minneapolis garden center found a large caterpillar. Initially, they said it was found amongst some cut flowers the store received from California. They submitted the caterpillar to the Entomology Department. This caterpillar, measuring three inches long, was light green on the lower half of its body and a reddish orange striped pattern on top. After a quick check of the references, it was determined to be a ficus sphinx, (sometime called fig sphinx), Pachylia ficus.

Like the name suggests, the preferred food of this caterpillar is different species of Ficus plants. It has also been reported feeding on mangos. But don't expect to find this insect on the Ficus in your home or office. A ficus sphinx is a tropical and subtropical insect that is found in northern South America, including Uruguay, Brazil, Bolivia, Central America, the West Indies, and occasionally ranging into Florida, southern Arizona and Texas. Of course, it is can be found in other areas of the country when it hitches a ride on Ficus plants that are transported north but this is rare.

The coloration of the caterpillar is quite variable including greenish and brownish forms. Interestingly, when diagonal stripes are present they slope away from the tail which is unusual for sphinx moths. Some individuals undergo a dramatic color change to green with an orange back, like was found, just before it pupates. The characteristic horn or tail that most sphinx caterpillars possess is greatly reduced to just a nub in this species.

ficus sphinx female - Dan Janzen.jpg
Female ficus sphinx moth
Dan Janzen
The caterpillar pupates on the ground amongst leaf litter and other plant debris. An adult ficus sphinx has orangish brown forewings with a light colored patch near the tips while the hind wings are orangish brown with a black band across the wing along with a black border along the edge. This moth has a wingspan between 4 3/4 - 5 ½ inches.

When the gardening center was called back to notify them of the identification of the caterpillar, they said that after a little more investigation they actually discovered that the insect was not found in cut flowers but on a Ficus which of course made perfect sense.

University of Minnesota 2009 Annual Flower Trials

Karen Jeannette, Horticulture Research Fellow & Yard and Garden News Editor

Black Pearl_medium.jpg
Ornamental Pepper 'Black Pearl' was
a top10 performer in St. Paul, but
 grew less profusely in Morris
and Grand Rapids, MN locations
Karen Jeannete
Each year researchers and scientists from the University of Minnesota, Department of Horticultural Science grow, display, and trial hundreds of annual flowers at several Minnesota locations, then report how well these annual varieties perform for that season. 

For Minnesota gardeners and industry professionals, the yearly University of Minnesota Annual Flower Trial sheds some light on how certain annual flower varieties will perform under different Minnesota conditions, and which ones are top selections for Minnesota overall.  St. Paul, Morris, and Grand Rapids, Minnesota were home to the 2009 display and trial gardens, as in past years.  These locations differ in their hardiness zones, heat zones, and growing days (see the section Top 10 Performing Annuals for 2009 by Site for details).  2009 Annual Flower Trial winners had to perform well despite cooler than average conditions through much of the summer growing season (Grand Rapids reported growing degree days for June through August were 16% below the 30-year average), followed by warmer than average September conditions. Thus, making for a somewhat challenging year for many annuals, especially those that perform best under warmer summer conditions.

Criteria for evaluating the 2009 annual flower trial cultivars include whether they were diseased (no/yes), average flower size, plant uniformity (1=poor, 5=excellent), and plant and flower ratings (1=poor, 5=excellent).  

 With differences in growing conditions across the state, having a top ten list for each annual flower trial location can prove helpful for gardeners trying to select varieties that perform well in similar growing conditions. Here are the 2009 top performing annuals by site:

Top 10 Performing Annuals for 2009 by Site

St. Paul, MN (USDA Winter Hardiness Z4; Heat Z5; 169 growing days)
Neil Anderson, Floriculture Breeding, Associate Professor, Department of Horticulture Science
FlowerTrial 2009-1-1.pdf (page 8 of 31).jpg
Photo 2: Les Bolstad Golf Course, St. Paul 2009. Annual Flower Trial report.
1. Colocasia 'Heart of the Jungle'
2. Millet 'Jade Princess'
3. Petunia 'Debonair Lime Green'
4. Petunia 'Pretty Much Picasso'
5. Petunia 'Sophistica Antique Shades'
6. Ornamental Pepper 'Black Pearl'*
7. Osteospermum 'Asti White'*
8. Gaillardia 'Mesa Yellow'*
9. Dianthus 'Bouquet Rose'
10. Carex 'Graceful Grasses Toffee Twist'

*=All American Selections cultivar

Morris, MN (USDA Winter Hardiness Z3/4; Heat Z4; 144 growing days)
Steve Poppe, Horticulture Scientist,  West Central Research and Outreach Center

Photo 3: Coleus 'Trusty Rusty'. 2009 Annual Flower Trial report
1. Petunia 'Ray Purple Vein'
2. Lobelia 'Techno Heat Upright Blue'
3. Petunia 'Suncatcher Red'
4. Geranium 'Calliope Scarlet Fire'
5. Petunia 'Supertunia Vista Bubblegum'
6. Diascia 'Flirtation Orange'
7. Coleus 'Trusty Rusty'
8. Begonia 'Braveheart Rose Bicolor'
9. Viola 'Skippy XL Red-Gold'
10. Verbena 'Superbena Coral Red Improved'

Grand Rapids (USDA Winter Hardiness Z3; Heat Z3; 109 growing days)
Shengrui Yao, Research Fellow, Grand Rapids, MN

Petunia-Supertunia Vista Bubblegum.jpg
Photo 4: Petunia 'Supertunia Vista Bubblegum'. 2009 Annual Flower Trial report.

1. Petunia 'Pretty Much Picasso'
2. Petunia 'Supertunia Vista Bubblegum'
3. Ipomoea 'Illusion Midnight Lace'
4. Delphinium 'Diamonds Blue'
5. Lobularia 'Snow Princess'
6. Cyperus 'Graceful Grasses King Tut'
7. Verbena 'Lanai Royal Purple'
8. Colocasia 'Heart of the Jungle'
9. Cleome 'Senorita Rosalita'
10. Rudbeckia 'Denver Daisy'

All American Selections

All three Minnesota flower trial locations involved in the 2009 Annual Flower Trial are also All America Selections Display Gardens, (AAS) since 1990, and grow the AAS winners from the past five years. The AAS Award recognizes a flower or vegetable variety proven to be superior to all others on the market.  In 2009,  St. Paul was the only Minnesota location with All American Selection cultivars in its Top 10 Performing Annuals list. There were, however, four AAS cultivars highlighted as performing good or excellent at two or three Minnesota trial locations under 2009 conditions. These highlighted AAS cultivars include:
  • Celosia 'Fresh Look Gold'

  • Nicotiana 'Perfume Deep Purple'

  • Petunia 'Opera Supreme Pink Morn'

  • Salvia 'Evolution 

The Full 2009 Annual Flower Trial Report

So which other annual flowers performed best across Minnesota locations?  Evaluation data for hundreds of annual flower cultivars can be found in the full 2009 Annual Flower Trial report.  Highlighted in grey are cultivars rated as good to excellent under 2009 conditions for at least two or three locations.  See page one under Flower Cultivar Evaluation Data to gain further insight as to how these highlighted cultivars are evaluated for the 2009 Annual Flower Trials. The report can be read here:

FlowerTrial 2009-1.pdf

The 2009 University of Minnesota Annual Flower Trials certainly give us an idea of which annual flowers performed the best under 2009 growing conditions.  Now it's up to Minnesota gardeners and nurseries to continue evaluating these new flower cultivars in 2010 under a new year's growing conditions, in new sites, and with different caretakers. May the best varieties win!

January 2010 Garden Calendar

Contributors: Karen Jeannette, Research Fellow and Yard and Garden News Editor, Michelle Grabowski, Extension Educator, and excerpts from the 2010 Minnesota Gardening Calendar.

January Tips


  • Pay special attention to your houseplants to keep them looking healthy
    this winter. Sun is weaker and days are shorter, so move plants to
    brighter windows if possible. Combat low indoor humidity by grouping
    plants together, checking their soil frequently and watering thoroughly
    with room temperature water whenever the soil feels dry a little below
    the surface. Wipe stems and leaf surfaces (upper and lower) with a
    soft wet rag to remove dust and allow maximum light penetration.  Find more information in the Gardening Information houseplants section. -- This is a 2010 Minnesota Gardening Calendar Tip.
  • The low humidity of most MN houses means that many fungal
    and bacterial leaf spots and blights do not thrive on houseplants during the
    winter months. Root rots however can be a problem for overwatered plants. To
    avoid root diseases, use pots that have drainage holes at the bottom. Choose a
    potting media that provides appropriate drainage. Before watering, test the
    potting soil with your finger to determine if the plant needs water. Heavy
    water logged soils that are never allowed to dry out will encourage root
    rotting fungi and can result in the wilting and death of infected plants. Find more information about houseplant diseases in the Gardening Information houseplant diseases section. --Michelle Grabowski, Extension Educator


  • Spread sand on icy sidewalks, rather than commercially prepared ice-melting chemicals, all of which are potentially damaging to nearby plants.  Even fertilizer (sometimes suggested for its ice melting properties) can burn plant roots where it accumulates.  To get sand to adhere to the ice, dampen it with a little hot water then throw it sideways, so it skitters across the ice.  In spring, sweep it off hard surfaces for re-use. It poses no harm to surrounding soil. Find more about plants and ice-melting chemicals by viewing the brief: Effects of De-Icers on Trees and Shrubs  -- This is a 2010 Minnesota Gardening Calendar Tip.


The Northern Green Expo, January 6-8, 2010 The Minnesota Green Expo is now The Northern Green Expo and one of the largest Horticulture Expos in
the nation. It is geared towards all sectors of the Horticulture/Green
industry (arborists, florists, nurseries, greenhouses, landscapers,
turf specialists, groundskeepers, etc.) More information can be found at:
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