CO-Horts Blog

Thursday, May 29, 2014

Perennials that make you go "Ooooooh!"

Posted by: Alison O'Connor, horticulture agent in Larimer County

I never feel like I’m on top of trends, whether it be clothing, cars or electronics. [Really? It’s not fashionable to wear plaid pajama pants in public?] And when it comes to my garden, I tend to stick with plants that are “tried and true.” Sure, I've planted a few novelties in the past—some make it; others turn into compost. Most of my experiments are planting vegetable cultivars that I never eat.

My brother works for a large wholesale nursery in Oregon, and a few weeks ago I was telling him (whining, really) about all the plants in my garden that didn't make it through the winter. Being the nice brother he is, he sent me a plant care package! With fabulous perennials! I’d heard of a few, but most I had to Google to get an idea of what they looked like...and find out their mature size.

I have a Heuchera (coral bells) collection, which is where most of my "popular" plants are located. Anytime I see a coral bell that I don’t think I have, I buy it or ask Jeff to find it for me (remember he lives in Oregon—the mecca of the plant world). Plus the names make you salivate: Caramel, Southern Comfort, Blackberry Crisp, Chocolate Ruffles, Peach Melba, Lime Marmalade, Berry Smoothie, Grape Soda. Truly, I've lost count of the ones I well as all the name tags. But these plants do really well in my part-sun garden with minimal irrigation. They do need to be mulched prior to winter and are slow to wake up in spring, but I adore coral bells, especially the flowers that dance above the foliage. And hooray—they are rabbit resistant!
[Photo from Terra Nova Nursery:]
Blackberry Crisp coral bells
I am also the proud owner of the 2014 Perennial Plant of the Year: Panicum virgatum ‘Northwind’. Switchgrass. Just the name alone sounds like fall. Switchgrasses are drought tolerant, sturdy and stay as a nice clump. Northwind’s foliage turns gold in fall. Can’t you just picture the fall sun glinting through the leaves? Wow. A 2014 plant of the year in my garden! Check out more on the Perennial Plant Association.
[Photo from the Perennial Plant Association:]
Northwind switchgrass in fall
Another Panicum in the shipment was ‘Shenandoah’. Jane Rozum, who just graduated from CSU and is now the hort agent in Douglas County, had this species in her ornamental grass trials. Let me tell you—I love this grass. Green foliage turns to maroon foliage in fall with ruby-colored wispy flowers. It is awesome. I’m so excited to welcome this to my landscape. It’s big too, with a height of up to 6’ and 3’ spread.
[Photo by Jane Rozum]
Shenandoah switchgrass
Another grass in the package was prairie dropseed (Sporobolus heterolepis). No, this isn’t a new plant or a fancy cultivar, but it’s a fantastic ornamental grass. And guess what? It’s a native! It’s tough, drought tolerant, virtually pest-free and really pretty.
[Photo by Karl Foord, University of Minnesota]
Prairie dropseed
He also sent a Stachys (which most of you know as the genus lamb’s ear). I have an extreme fondness for lamb’s ear. I fell in love with this fuzzy darling during my undergrad and joked that one day I would have a lawn of lamb’s ear in which to roll around. Though many hate the flowers (I simply cut them off) and it’s in the mint family (i.e. aggressive), lamb’s ear is a great selection for spaces where you need to fill large gaps in dry places. But the Stachys my brother sent is actually Stachys officinalis ‘Pink Cotton Candy’ (a cousin of the plant we know). Now, I don’t know much about this plant, except for the pictures I saw online, but it’s a clump-former with pale pink upright flowers. It blooms in early summer and will repeat bloom if flowers are cut back. Has anyone grown this in Colorado…or was this plant so-2004? I'm excited about it.
[Photo from Chicagoland Grows(R):]
Pink Cotton Candy Stachys
[Photo from Chicagoland Grows(R):]
Ooooh...fantastic pink flowers!
I’m looking forward to seeing these plants sleep (first year), creep (second year) and leap (third year). Just like my ginkgo…which, by the way, is fully leafed out!

Wednesday, May 28, 2014

Sixty Second Secrets: Farmers Markets!



Today on Sixty-Second Secrets for Gardening Success: Farmers Markets!


Farmers Markets are a quintessential part of summer. Farmers markets provide an integral link for communities and local agriculture to come together to provide high quality direct-to-consumer marketing which strengthens local economies.
To help you enjoy and maximize your time at the markets this summer, here are a few helpful tips:
·       Some farmers markets accept SNAP and WIC as a form of payment. Check with your local market or vendors to determine what methods of payments they accept.
·       Shop early for best selection.
·       Wear sunscreen.
·       For items that need to be kept cool, bring an insulated bag or ice cooler.
·       Bring reusable bags, and your camera! There are plenty of good photo opportunities at your local market.
·       Take the time to get to know your local vendors. They may offer more than what they sell at the market.
·       Ask the vendors for ideas and try something new every week, you may discover your new favorite dish.
For more information on farmers markets, contact your local CSU Extension Office or visit

Sixty-Second Secrets for Gardening Success is a production of Colorado State University Extension
CSU Extension: Extending knowledge, changing lives.

Tuesday, May 27, 2014

It's Electric! (Mower Edition)

Posted by: Linda Langelo, CSU Extension horticulture program associate, Golden Plains Area

(photo courtesy of
The Lawn Hog, Black and Decker MM875
I purchased an electric mower two years ago because they are lighter to operate and I didn't have to handle the gas all the time.  It just didn't make any sense to drive the empty can of gas to the gas station to get gas.  Let’s face it--how conservative is it to use gas to get gas? 

The good news is I am not counted among one of the statistics recorded by Environmental Protection Agency when they announce smog-producing emissions from today’s gas powered mowers.  More importantly, we need to pay attention to alerts about ground ozone caused by gas, paint or solvents evaporating and releasing reactive organic compounds.  Together the heat and the sunlight create a reaction with the emissions of organic compounds.  On days like this, ozone gas contributes to higher risk for people with asthma and other respiratory ailments.

According to the EPA, using your gas powered mower for one hour causes more air pollution than driving 292 miles round-trip from Madison, Wisconsin to Chicago, Illinois.  In comparison, an electric mower draws as much electricity as it takes to operate a toaster. Yes, a toaster!

In today’s market you can purchase an electric mower without a cord.  Besides the cord issue, I have freed myself from keeping gas on-hand and the yearly maintenance of a gas powered mower.  With an electric mower you don’t need to change an air filer and spark plug every year.  But you still have to sharpen the blades and balance them.  Sharp blades give the grass an even cut and make the grass less prone to disease.

Electric mowers are easier on our hearing.  The decibel level of electric mowers can be from 65 to 85, but gas mowers run about 90 decibels. Normal conversation level is about 75 decibels.  A sudden loud noise or prolonged decibel level starting at 85 decibels or higher can cause hearing loss. 

With an electric mower, it can handle lawns with fine or tall fescue and bluegrass.  Electric mowers do not do as well with zoysia or buffalograss.  You need to assess your situation before purchasing an electric mower. 

If you really want to go green and keep healthy, purchase a reel mower.  The only maintenance would be keeping the blades sharp.  The rest is up to you, just push and go.

Friday, May 23, 2014

What is that strange little yellow-green flower?

Posted by Irene Shonle, CSU Extension in Gilpin County
Almost every spring, someone brings me a picture or a plant of a strange little flower they’ve never seen before, and can’t key out or even begin to guess the family for. 

 Here it is:


Any guesses before you keep reading?  I’ll admit, this had me stumped at first, too.

It is Fendler’s rockcress (Boechera fendleri) attacked by a rust fungus called Puccinia monoica.  Surprised?

This rust attacks 11 different genera, all within the mustard (Brassicaceae) family.  The fungus infects the host plant in the late summer via wind-blown  basidiospores. The fungal hyphae germinate and then parasitize nutrients from the host plant. The fungus requires an alternate host, a grass, where the basidiospores will develop to continue the cycle.  So far, pretty standard fare for rust fungi.

What makes this particular fungus so cool, though, is how it completely hijacks the plant in order to reproduce sexually.  First, it inhibits true flowering in the host and then it causes the plant to create yellow-green pseudoflowers.  The shape and the color visually mimic other spring flowers (even under UV light) – and  these ‘flowers’ fool insects into ‘pollinating’ them  (the insect visits transfer spermatia from one infected plant to another)!  As Barbara Roy states in her “Letter to Nature” describing this phenomenon, it is truly an “ extraordinary case of pathogen-mediated floral mimicry.” (

To more fully dupe the unsuspecting insect, the fungus goes even further and causes the plant to produce both a scent and a nectar reward.   In a study published in Molecular Ecology in 2002 (, Raguso and Roy found that the pseudoflower fragrances were very different from the host flowers, host vegetation and the flowers of other plants blooming at the same time.   In fact, the fragrance was chemically similar to completely unrelated noctuid-moth-pollinated flowers, such as Cestrum nocturnum (night-blooming jasmine).  The uniqueness of the scent is hypothesized to make sure that the visiting insects stay true to the fake flower.

Here is a picture of the Rockcress when not parasitized – you can see why you’d never think it was the same plant:

Fendler's rock cress in its 'normal' unparasitized state.  Photo credit: Max Licher,
Here is a link to more pictures of the plant, both paratisitized and unparasitized:

What an interesting world we live in!

Weed of the Moment: Kochia

Posted by: Tony Koski, Extension Turfgrass Specialist

Kochia (ko-sha) (Kochia scoparia) is a very common weed found everywhere in Colorado. It can be found in rangeland, pasture, gardens, ditches and on small acreages--essentially anywhere with disturbed soils. Kochia is a native of Asia and was introduced from Europe. As a summer annual, it begins germination in early spring. With its fuzzy gray leaves, as a small plant it's not unattractive, since it forms a dense mat on bare soils. [Note: I once was asked by a homeowner if she could have a kochia lawn, since she thought it was so pretty.]
Young kochia just after germination.
As summer progresses, the plant grows taller and looks like a gangly teenager, until it breaks off in fall, turning into tumbleweeds as large as 6 feet tall. And that's how the seeds disperse. Thousands and thousands of 'em. If you've ever driven on E470 to the airport, you've likely smashed one into smithereens.
Tumbleweed. It's a big 'un!
If you have kochia in your landscape, pull it or control it while it's young. It's much easier to control as a young seedling. Plants have a very shallow taproot and can easily be pulled or hoed. A thick layer of mulch can be very effective in helping control kochia. Kochia can be controlled using a non-selective herbicide like glyphosate (Roundup) when it is young (less than 12 inches tall); mature kochia is very resistant to glyphosate and just about any other herbicide. When using glyphosate for kochia control, complete coverage of the weeds is essential or you will have poor results. Remember to apply all herbicides according to the label. Focus your efforts on cultural conditions and management. It's rare to have kochia in the lawn, unless you have thin, bare areas.
Invasion of the tumbleweeds! A backyard in Pueblo.

Wednesday, May 21, 2014

Dependable Landscape Trees from the Colorado State University Arboretum

Posted by: James E. Klett, Extension Horticulture Specialist

A new publication (Bulletin XCM -150), Dependable Landscape Trees from the Colorado State University Arboretum, was recently published by Colorado State University Extension authored by Sarah Shaub, M.S and James Klett, Ph.D.  It is a collaboration between Colorado State Extension, Colorado State University College of Agricultural Sciences and Colorado Agriculture Experiment Station.  

The book is available from CSU University Resourse Center, 115 General Services Building 4061 Campus Delivery, Fort Collins, CO 80523, Phone (970) 481- 6198, or Cost: $19.95, plus shipping and handling. 

The Colorado State University Arboretum is located at the Plant Environmental Research Center (PERC) located in the southwest corner of the main campus (630 W. Lake Street in Fort Collins).  The main objectives of the arboretum are to determine which plants are suitable for growing in the Rocky Mountain area and to display the plants for teaching and public viewing.  The PERC arboretum contains more than 1,100 different plants with an additional 120 taxa located at an additional six acre arboretum on Center Avenue in Fort Collins.  The plants discussed in this publication are based on data collected between 1997 and 2012.  Every plant in the arboretum is evaluated every two years using a standard evaluation form comprised of 31 parameters relating to plant characteristics, aesthetic value, plant health, insect and disease problems and cultural and maintenance problems.

The plants discussed in this publication needed to be growing a minimum of 10 years in the arboretum and then ranked on two evaluations parameters: overall health and aesthetic value.  Plants were ranked and given an assigned ranking; a minimum point cut-off eliminated less suitable plants for the region.  This selection process yielded the 225 trees discussed in the publication.  Both deciduous and evergreen trees are arranged by scientific name in alphabetical order of each section in the publication.  Each plant entry lists the years transplanted, 2012 height and width, mature height and width, growth habit, landscape uses, flowers, fruit, fall color, pests and potential problems.

Along with the list of general plants characteristics, a description of each plant is provided.  This is a summary of the main landscape features of the plant.  Entries for tree cultivars include a shorter description, with the primary information provided being the main characteristics of the cultivar that differ from the species. 

The performance section of each entry is a summary of the evaluation data for each numerous plant.  If any characteristics of the arboretum are different from what is expected, it is indicated here.  Photographs of most of the trees are adjacent to the plant characteristics. 

There are also numerous appendixes in the book including: list of plants that did not meet the criteria for number of years in the arboretum, list of plants still under evaluation, list of trees by flower color, fruit color, landscape uses, mature size and fall color.  Descriptions of the plants normally have three photos accompanying the description often showing growth habit, flower and fall color.

Many foundations and organizations contribute yearly funding to operate the arboretum along with numerous nurseries and botanic garden providing plant material. This is a must-have publication for anyone recommending landscape trees for the Colorado and Rocky Mountain Area.

Tuesday, May 13, 2014

Soil Microbes: Your Silent Partner in the Garden

Eric Hammond- Adams County Extension

When most people think of bacteria, fungi and amebas they think of ear infections, sniffley noses, antibiotics and brain-eating single celled organisms contracted from improper use of a “neti pot” (maybe that last one is just me).  However, the soil in your yard in garden is full of these microscopic organisms as well as many others like nematodes, algae and actinomycetes (a word which I have not once pronounced correctly in my entire public life).  As the soil warms this spring they are starting to become more active and for the most part they are doing great things for your lawn and garden. 


Nutrient Cycling (Mineralization)-

Soil microbes feed on organic material decomposing it.  As they do this nutrients are taken from complex forms which plants can’t adsorb (or at least do not commonly absorb) to simpler forms that they can.  For example, in plant material nitrogen is incorporated into the molecules making up the plant’s DNA, cell walls and other structures.  As soil microbes digest this material some of this nitrogen is released into the soil solution as ammonium or nitrate, the two forms of nitrogen commonly absorbed by plants.  Without soil microbes plant nutrients in organic matter would remain tied up in unavailable forms.

Mineralization nitrogen from organic forms to nitrate- diagram by Ray Daugherty


Soil Structure-

Both soil microbes and larger soil fauna help build structure in soils.  There are several mechanisms through which this happens.   Some soil life such as earthworms create large continuous pores through the soil allowing for increased and deeper infiltration of air and water into soil.  Soil microbes affect soil structure by producing compounds that act as binding agents.  These compounds help the various elements of the soil (groups of clay platelets, chunks of organic matter, granules of sand and etc) aggregate, forming structures with a good mix of smaller pores that the can hold water against gravity and larger pores which drain rapidly and are commonly filled with air.
Desirable soil structure has a variety of pore sizes

Plant Symbiotic Microbes-

Some microbes have symbiotic relationships with plants.  Generally these relationships involve the exchange of carbohydrates from the plants in return for nutrients or water from the soil microbes.  The two most common examples of these types of soil microorganisms are Mycorrhizal fungi and Rhizobia.   Mycorrhizae are a group of symbiotic fungi that grow in association with plant roots.  They receive carbohydrates from the plant and in return supply the plant with water and nutrients- most commonly micronutrients and phosphorus.  The fungi are better able to extract tightly held soil water and less soluble forms of some of these nutrients than the plant.  It should also be noted that these relationships are species specific.  A given species of Mycorrhizae form symbiotic relationships with specific groups of plants.  Rhizobia are a group of bacteria which colonize the roots of the legume family.  They are capable of fixing gaseous atmospheric nitrogen into a form that the host plant can use.  In return the plant supplies them with carbohydrates.
The white hairs are Mycorrhizal fungi

Encouraging Beneficial Soil Life

There are a few simple things that we can do as gardeners to encourage these beneficial soil organisms.  Happily, many of them are things we already do to encourage good health in our plants (what a coincidence). 

1) Provide a good habitat-

Soil microbes need both food (organic material) and oxygen to complete their life cycles.  In natural systems, organic matter is added each year through natural cycles (think of leaves dropping in the fall in a forest).  In some portions of urban landscapes we can adopt practices that mimic this.  For example, we can leave grass clippings on the lawn or mulch leaves into the turf in the fall instead of raking them up.  In other areas, like a vegetable garden, organic matter must be added to replace that consumed by soil microbes.  Generally 2”-3” of plant based compost or 1” of manure tilled in at least 8” deep is the recommended application rate for vegetable gardens or annual flower beds (more information here). 

Potential soil organic matter is often removed from landscapes

Soil microbes need oxygen to perform respiration (the process which turns carbohydrates into energy).  So taking steps to alleviate and\or avoid soil compaction (which reduces the amount and size of large air-holding pores) such as regular aeration of lawns, raised bed gardening and using wood mulch around perennial beds, trees and shrubs may also encourage beneficial microbes.

Basic formula for respiration
2) Avoid excessive tilling or other disturbances when possible especially if the soil is very wet-

Such practices can have a number of negative effects on soil microbial populations.  They can destroy aggregates, degrading the soil’s structure, which in turn can create issues with aeration and drainage.  This is especially true if a more aggressive form of tilling such as rototilling is used at a time when soil aggregates are already fragile, such as when they are very wet.  Such practices also increase the rate of decomposition of soil organic matter by exposing it to the oxygen in the atmosphere.   Excessive tilling can also harm soil microbes by physically damaging them.  Fungi and actinomycetes are particularly at risk because of their larger thread-like bodies.

This is the great paradox of organic amendments and soil life.   There are situations where we need to add them to the soil regularly to replenish soil organic matter.  However, in doing so we are disturbing soil life and degrading its habitat.  We can minimize the damage by using less destructive methods to amend.  For example, instead of using a rototiller to mix in annual amendments, consider an old fashioned shovel or a broadfork (there are several informative videos about the use of broadforks that can he found here -no endorsement or criticism of these specific products is implied).

There is a lot of discussion about whether or not inoculating your soil with microbes is helpful.  I won’t rehash it here, but you can find a bunch of discussion about it on the garden professors blog.  Here is my attempt to sum up the topic in few sentences:  If the soil has conditions favorable to beneficial soil life (well aerated, moist and has adequate organic matter) you probably already have a healthy population of soil microbes or will develop one over time.  If a soil is low in organic matter and\or is poorly aerated any soil microbes which you add are unlikely to thrive anyway.    

There are some proven benefits to specific inoculations.  For example in a first time garden inoculating the soil with Rhizobia maybe beneficial if you are growing beans peas or other legumes.  Likewise specific species of Mycorrhizae may be used to aid in the production of specific plants, however, research on their wider use is mixed.

More information on soil life can be found in Colorado Master Gardener Garden Note #212 

Monday, May 12, 2014

Plant Sale in Denver this Weekend!

By Alexis Alvey, Horticulture Agent, CSU Denver Extension

The Denver Master Gardener 9th Annual Spring Plant Sale will take place this weekend, May 17th and 18th!  On Saturday, doors will open early at 8:00am and stay open till 3:00pm.  On Sunday, the sale begins at 10:00am and ends at 3:00pm.   The sale is located in front of the CSU Denver Extension office at 888 E Iliff Ave, Denver 80210, in the northeast corner of Harvard Gulch Park, with the cross-street being Emerson.

The Spring Plant Sale offers a unique variety of heirloom and modern tomatoes, sweet and hot chili peppers, select vegetables and herbs, and annual and perennial flowers.  Denver Master Gardeners have been working hard all spring in the City Greenhouses in Denver City Park, operated by Denver Parks & Recreation, growing almost all of the veggies and herbs available at the plant sale.  It has been a great opportunity and hands-on learning experience for the Master Gardeners.  Working alongside Parks & Rec staff, they began seeding in March and have provided the tender loving care that each plant deserves.  The plants are now super healthy and ready to be taken to your home!  Below is a list of all the varieties being grown by the Master Gardeners.  The remainder of the plants are obtained from Colorado nurseries and helps support the local horticulture industry.

At the Spring Plant Sale, Denver Master Gardeners will help answer any of your gardening questions and will help you choose the best plant varieties for your particular needs.  All proceeds from the sale support the CSU Denver Extension Horticulture Program.

The Spring Plant Sale is a great community event, so make sure to stop by the other booths including Plant-A-Row for the Hungry where you can get free seeds!, the gently-used gardening items for sale booth, the Rosedale-Harvard Gulch Neighborhood Association, and the 4H Kids-Grown booth!  For more information, call 720-913-5270.  The event is rain or shine (or snow!).  Cash only, please.  See you there!

Sunday, May 11, 2014

Knock it Off: Preventing Snow Damage to Trees

Posted by: Alison O'Connor, Larimer County

Mark your calendars, folks! It's Mother's Day, May 11, and the snow is coming down fast and furious. By the time it's all said and done, up to 9-12" of wet, heavy snow (yea moisture!) is expected, but for our woody plants that have leafed out, this means bad news and possible damage.

So take precaution now and go and gently knock the snow off the trees and shrubs (and perennials) that have been coated. The leaves capture a lot more snow per surface area than branches, and this is what makes branches droop and break. Evergreens also need attention.

Shaking off the snow is one of the best things you can do to prevent damage...and you may have to repeat this a few times until the snow stops. But be gentle--don't vigorously shake, just do some light taps or brushing.

The mighty broom handle!
The "weepy" star magnolia outside the hort building.
Tap, tap, tap.
Free from snow and ice (the blue spruce is another project).
By the way, the turf specialist said your lawn is fine.

Wednesday, May 7, 2014

Sixty Second Secrets for Gardening Success: Master Gardener Plant Clinics

Today on Sixty-Second Secrets for Gardening Success: Master Gardener Plant Clinics.

Have you ever seen a flower and wanted to know what it is, or ever had your lawn or favorite plant suddenly start looking sick and wanted to know why?

You may not realize it, but expert help may be right around the corner!

Colorado Master Gardener volunteers are trained to help you in plant ID as well aiding in diagnosing what is wrong with a sick plant or lawn.

Plant clinics take place at many locations around the area. Many are held at the County Extension Office while others may be at the local nursery or garden center, your favorite big box store, or at your community
farmers market.

For more information on plant clinics, contact your local CSU Extension Office  or visit

Sixty-Second Secrets for Gardening Success is a production of Colorado State University Extension.
CSU Extension: Extending knowledge, changing lives.

2014 Cool Season Plant Trials at CSU

Posted by: James E. Klett, Professor and Extension Specialist, Landscape Horticulture

Growers, landscape contractors and homeowners will want to plant some of these winners in their gardens in the fall of 2014 from our 2013-2014 Cool Season Trials.  These trials included 66 different varieties of cool season plants.  These plants were planted on October 8, 2013 and grown through the fall, winter and early spring of 2014.  Additional water was added to these trials a total of nine times from October 8, 2013 to April 21, 2014.  Watering was done when temperatures were above 40 degrees Fahrenheit and soil was dry.  Our lowest temperature recorded during the period was -15 F.  We did have fairly constant snow cover in January and February 2014.  We recorded frost damage, flowering data and overall appearance on a weekly basis when not covered in snow.

The Annual Trial Garden Committee evaluated these Cool Season Trials in April 2014 and picked six top performers which are described below. The six winners include:

Best of Show Pansy:  Pansy Inspire R Purple and White from Benary
Nothing says “best of” like 100%  survival through the winter season.  This pansy has very bright and high contrasting purple/blue white flowers.  The flowers seem to have a blue top and a white bottom that make them very visible from quite the distance.  
Inspire Purple and White pansy

Blue/Violet Pansy: Pansy Inspire R True Blue from Benary
This variety had the largest flower out of any of the Pansies; these large blue flowers made this plant a standout.  In addition to the large flowers it was also noted that it had the truest blue flower.
Inspire True Blue pansy
Best Yellow Pansy:   Pansy Cool Wave TM Golden Yellow from PanAmerican Seed
This pansy had a profusion of large, attractive bright golden yellow flowers.  The flowers are a bright golden yellow that is sure to catch the garden visitor’s eye due to abundance of flowers.

Cool Wave Golden Yellow pansy
Best of Show Viola:  Viola Sorbet EX Morpho from Pan American Seed
This viola was described as a sturdy, small, uniform plant.  The flower color is a very rich combination of deep blue and canary yellow.  This color combination gave the plant a great contrast, allowing it to become a garden favorite.  This Viola also had a 100% survival rate during the winter.
Sorbet EX Morpho viola
Best Blue/Violet Viola:  Viola Penny Deep Marina from Goldsmith Seeds
This viola had a unique flower color combination of deep purple, purple and white.  These plants were very uniform in growth habit and each plant was just blanketed in flowers.
Penny Deepy Marina viola

Best Yellow Viola:  Viola Popsicles Yellow from Burpee Home Garden
This viola seemed to have the most intense yellow flower color.  The yellow flowers had a golden yellow throat that made it standout even more.  All of the flowers were displayed perfectly on top of the foliage of the plant.  It was also noted that this Viola was a great, sturdy plant.
Popsicles Yellow viola