CO-Horts Blog

Monday, May 30, 2016

Peonies: Oh how I love thee

Posted by: Alison O'Connor, Larimer County Extension

Peonies = love.
Last week we had a statewide horticulture agents meeting in Grand Junction, Colorado. Imagine over 20 "hort nerds" gathering to talk plants, Extension, volunteer management and a little bit of everything else. On Monday, we spent the day touring five wonderful places throughout the Grand Valley. Thanks to fellow CO-Hort Susan Carter for arranging the amazing tour!

My favorite stop, by far, was Arcieri's Peonies in Grand Junction. For those of you unfamiliar with Colorado's West Slope, their growing season is easily two or three weeks ahead of the Front Range. Their peaches were the size of walnuts and many of the roses were in full bloom. Just like the peonies.
Arcieri Peony Farm
Peonies. Is there a better flower? Is there a flower that brings up more nostalgia and memories of "Grandma's garden"? There isn't a flower I love more--peonies are my hands down favorite. They are a great cut flower, are a low maintenance perennial and can live for decades. And they do really well in Colorado's arid climate. But you do have to have patience with peonies. These beauties like to take their time after planting before they bloom. Don't count on reliable flowers until three to five years after planting. But it's worth the wait. It's soooo worth the wait.
Peonies are the best EVER! Look at those flowers!
When our bus pulled up to Arcieri's, there were audible gasps and oohs and aahs. The fields (a little under six total acres) were bursting with peonies in full bloom. And the smell was heavenly. I would put a peony head-to-head with a rose for best scent any time. It's intoxicating. All of us departed the bus and immediately went and stuck our noses into the blooms. 
Sniff deeply, enjoy and repeat often.
Jim Arcieri, his wife and his sister run the family owned-and-operated farm. Jim's parents started the farm in 1929 and most of the peonies are over 80 years old! Can you imagine? We get excited if a tree lasts for 50 years...and here are these humble perennials that faithfully bloom every year. Incredible. 
Mr. Jim Arcieri of Acieri Peonies.
The family was finished with shipping and cutting for the year. Their rule of thumb is to not remove more than 25% of the flowers from each plant to sell as cut flowers. That means that the rest of the flowers will be allow the plants to put energy into photosynthesis and food production. All those flowers! I'm so glad we were there to enjoy them.
Love. Love. Love.
If you grow peonies at home, the ideal time is to cut them when they are in the "soft marshmallow" stage. The flower bud should be large and plump and somewhat squishy. This will allow the buds to gently open and maximize the time in a vase. But you can cut flowers that are more open...just realize their time as a cut flower will be reduced. Ideally, stems should be cut to 12" long. After cutting, immediately put the stems in water. The buds will open over a few days and most peonies can last at least a week (usually longer). And yes, you too should remove the flowers that you don't enjoy indoors as cut painful as it is. This really will allow for better blooms each year. Just snip the flower head off, but leave the stem.
Peony buds sometimes look like rose buds!
This is almost to "soft marshmallow" stage for harvest.
This peony is a little past soft marshmallow stage, but would still make a good cut flower.
Harvest peonies early in the morning or at dusk...avoid cutting during the heat of the day. During peak production the Arcieri's have two cutting shifts. Believe it or not, their harvest season is only two weeks long!

Arcieri's Peonies are shipped mostly to the Denver area and sold locally in the Grand Valley. They also do some sales from the farm. They welcome visitors and are always happy to give tours. If I lived in Grand Junction, I'd stop by all the sniff the flowers, enjoy the blooms and take home a bouquet. For every room in my house!
Peonies cut, bundled and ready to ship!

Thursday, May 26, 2016

Best of the National Ornamental Grass Trials, Colorado Edition

Jane Rozum, Douglas County Extension
Ornamental grasses are indispensable for today’s landscapes. Not only do they have low water, nutrient and maintenance characteristics, but they give a unique and naturalistic appearance in both commercial and homeowner landscapes. They can function as a screen or background plant, accent more colorful plants, or stand alone in groupings. It is no wonder that sales of these resilient grasses have risen 61% in the last 10 years.  
The National Ornamental Grass Trials was launched in 2012. This three-year study at 17 sites around the country was coordinated by Dr. Mary Meyer at the University of Minnesota. Colorado State University participated in the trials and was the only site in the Intermountain West.  Twenty-two cultivars of Panicum (Switchgrass) and Schizachyrium (Little Bluestem) were included in the trial.  The trial evaluated whether the grasses survived minimal cultural inputs and also which plants thrive and possess desirable characteristics under Colorado weather conditions. All the grasses were watered at 50% of bluegrass reference evapotranspiration, which is about ½” of water per week, with no amendment to soil at planting or fertilizer for the duration of the trial. Wood mulch was added around the plants in 2013 to control weeds. Fall of 2015 was the last data collection.
Colorado State evaluated the plants using a landscape impact rating scale to rank each plant’s appearance and sustainability parameters. This scale ranks attributes such as growth habit, lodging, floral impact, winter injury and disease or insect damage. Overall, most of the cultivars did very well in the CSU trials.  We’ve included photos and descriptions of the best of the trial plants over the three years of the trial.

Panicum virgatum ‘Dallas Blues'

'Dallas Blues'

      ·         Selection from seedling in Dallas, Texas home landscape
·         Broad steel  blue to gray-green foliage, leaves ¾-1-1/2” wide; bold textured
·         Purplish panicle inflorescence
·         Mature height: up to 5 ½ feet
 Panicum virgatum ‘Northwind’
       ·         Selection from Northwind Perennial Farm in Wisconsin
·         Perennial Plant of the Year, 2014
·         Upright, narrow growth habit ; possibly a substitute for Calamagrostis x acutiflora ‘Carl Foerster’
·         Foliage blue/green, inflorescence green/tan
·         Mature height: 5 feet

Panicum virgatum ‘Shenandoah’
       Selected in Germany from seedlings of ‘Hanse Herms’
       Leaves initially green in spring, red in July, wine-colored in September
       Upright, broad growth habit
       Mature height: 4 feet in flower(tan)

Panicum virgatum ‘Thundercloud’
·         Upright vase growth habit
·         Wider, blue-green leaves up to 1 inch
·         Pinkish panicle inflorescence give appearance of cloud above leaves
·         Mature Height:  6 feet

Schizachyrium scoparium ‘Blue Heaven’™ (Minn Blue A)
 'Blue Heaven'
·         Upright, open growth habit
·         Light blue foliage
·         Fall color: Deep pink-burgundy with copper highlights
·         Mature height: 2 feet

Schizachyrium scoparium ‘Carousel’
       Compact, upright growth habit
       Blue-green-gray leaf color
       Fall color- copper, mahogany
       Mature height: up to 2 feet

Monday, May 16, 2016

2015-16 Cool Season Trials Yield Top Picks for Off Season Color

Posted by James E. Klett, Professor, Colorado State University, Department of Horticulture and Landscape Architecture.

One hundred and sixteen varieties were evaluated in the 2015-16 Cool Season Trials from planting in mid-October 2015 through April 2016. At the end of the observations, eight plants were selected by the Annual Trial Garden Committee as top-rated performers. All varieties were monitored and observed weekly during the trial period. Plants were watered when the soil was dry and the temperature above 40 degrees Fahrenheit, but we had good snow cover for about two months of the trial period.  The eight winners are listed below.

Best of Show Pansy
Cool Wave® Frost from Pan American. This is a spreading type of pansy and would be excellent for hanging baskets. This variety had good flower cover producing many blooms in a multi-color pastel blue and white.

Best Blue/Violet Pansy
Inspire® Plus Marina from Benary. This pansy had a soft blue color with a contrasting eye of golden yellow. This is a traditional more upright type pansy with a very uniform habit with short pedicels and upward facing flowers.

Best Yellow Pansy
Freefall® Golden Yellow from Flora Nova. This is again a spreading variety that would be excellent for baskets. The flowers are a clear golden yellow with prominent darker whiskers in center flower. It again provided excellent flower cover over the entire plant.

Best Orange Pansy
Spring Matrix® Orange Deep from Pan American. This is a new category for 2015-16 since we had a lot of orange pansy entries. It is a traditional more upright growing pansy with deep orange, frilly flowers. This variety overwintered extremely well.

Best Violas
Pan American Seed Company’s Sorbet® XP Series dominated in each of the categories in this year’s cool season trial.

Best of Show and Best Blue Violet Category
Sorbet® XP Beaconsfield Improved won in both of these categories because of its eye-catching bicolor viola with a deep blue/violet center that faded to a lighter blue/violet with a nice bright orange eye. It had excellent flower cover and overall would add great curb appeal.

Best Yellow Viola Category
Sorbet® XP Yellow Blotch from Pan American. The flower color was a deep yellow with a nice chocolate blotch. It had very uniform growth habit with strong flower stems and a very even flower cover.

Best White Viola Category
Sorbet® XP White Blotch. This variety had a very uniform and consistent growth habit with many flowers with very large flowers for a viola. The flower color was white with a bluish blush.

Best Novelty Viola

This is also a new class this year with Sorbet® XP Orange Jump Up winning the honor. Flowers were a stunning contrast of deep violet and vibrant orange and flowers showed no sign of fading.

Thursday, May 12, 2016

Sins of the Landscape

My fellow Horticulture Agents will agree; sometimes it is hard to drive around town and see the landscape “sins” that are going on.  One of our Tri River Area Master Gardeners recently wrote an article on trees.  It pained her to see them improperly planted, pruned or ignored.  Please do your homework.  Plant the right tree in the right place.
Plant using the latest updated planting techniques.
Do your homework before you prune.
If the tree is in the right place, you should have minimal pruning to do.  Always remove dead, dying and disease wood as soon as you see it.  And please never, never top a tree.  Some people will say they are pollarding.  Pollarding is started on saplings and was used in Europe to produce a quick large amount of wood that was then used for firewood.  “Pollarding”, aka topping, should never be done on large trees.  When topping is done, it is committing the tree to a short life.  Talk to your local Masters Gardeners about trees.  They will be happy to fill you in so you can grow trees that live longer than we do.  Leave a Legacy.
Right plant, right place

Now on to the next “sin” I witnessed driving home the other night.  A local business was laying weed fabric.  Well, the big problem with this is they were laying it over already existing fabric and decomposed granite rock.  Then they were putting a 1” or larger river rock on top.  I assume they were doing this to help conquer the weeds.  The problem, actually there is more than one, is first: old fabric gets dirt built up on it and it essentially clogs the pores of the fabric.  This dirt build up on top is why the weeds are now there.  Secondly, one has to understand the movement of water through different materials.  Water moves through one material before it will start to penetrate another layer.  These layers are called interfaces.  So by the time water moves through 4 layers of material how much is going to actually get to the soil below and to the roots of the plant.  The correct thing to do would be to remove the existing rock mulch and fabric and start over.  Or not use fabric to start with and use other methods to control weeds.

Dandelion photo by Susan Carter

Controlling weeds starts by identifying the weeds that you are trying to get rid of. We have winter annual weeds that start growing in late summer or early fall.  These them start growing like mad in early spring and are already setting seed at lower elevations.  Downey Brome, aka Cheatgrass, is one great example of a winter annual.  Then we have annuals that germinate in spring or summer.  Biennials type of weeds grow vegetation one year and bloom and go to seed the second year.  And perennial weeds are ones that will come up at least 2 years or more from the root system.  Woody weeds fit in this category.  Pre-emergents can be used to control weeds in areas like the rock mulch bed in my story, but it is important to know the identity of the weed or its life cycle so you apply the herbicide at the appropriate time.  Of course, manual removal of the weeds is one way to control them.  Spraying herbicide on them after they have germinated is another and trying to out compete them with properly grown turfgrass or cover crops is another. (Always read the label and follow instructions on pesticide labels.)
Feel free to take weed samples to your local Extension office.  Please bring the entire plant and if it is blooming, that is even better.  The more information we have, the better we can help you.  So do your homework, choose what works best for you and your landscape, to help you maintain a healthy landscape.   Blog posted by Susan L Carter, Horticulture Agent, CSU Extension Tri River Area

Tuesday, May 10, 2016

Spring Storms Damage Trees

By: Mary Small, CSU Extension, Jefferson County

Ouch! Our spring snowstorms have wreaked havoc on our trees and shrubs. Poor things, they have such a challenge growing in our climate to begin with, and then this: two snow events that snapped off branches and damaged some trees beyond repair.  My colleagues and I have been inundated with questions about how to handle these issues.

Cut back to branch collar 
The quick answer is it depends on the damage and the health of the tree. In this first photo, the branch should be removed back to the branch collar –which is the trunk in this case. Don’t just cut off the broken and split branch and leave a stub! Removing branches may make the tree look a bit bare (and maybe even odd!), but eventually the new leaves and branches will mask the damage.

Root breakage 
The pine tree was essentially tipped over and pulled out of the ground from the weight of snow on its branches, resulting in a lot of root breakage.  It’s best to remove this tree.

Lost leader
Some trees lost their leader. Tree owners can just let nature take its course;  the tree will develop a new leader from a side branch nearest the injury. They can also attach a stake to the top of the main stem and select a branch to take over as leader. The branch is bent upward (don't crack or break it!) and tied to the stake.

Honeysuckle - in the
In cases like this honeysuckle, where the branch broke off, the best course of action is to make the edges of the wound neat and clean, using a knife to remove and smooth the jagged edges.

 1st place for most creative "fix"!

I found this very creative (although ineffective) broken branch treatment in my neighborhood.  I’ll watch it over the next year or two and report back on its progress – or lack thereof!

Monday, May 9, 2016

The Answer: Iris "Accordians"

Posted by: Alison O'Connor, Larimer County Extension

Thanks for you comments...I laughed at the response that the plant didn't wear sunscreen (a good reminder to all of us!) and Dr. Steve Newman said a fellow Twitter follower said it was a result of listening to Lawrence Welk music.

My best guess...which was supported by fellow CO-Horts Mary Small and Tony that it's most likely freeze/chilling injury. Since it was the third leaf on both sets of plants, it led me to believe that these plants were damaged either in the bud or as they were emerging. The plants are located close to the home and are always early to emerge, so it was likely during one of those cold snaps we experienced in late March or early April. Also the leaves were likely constricted during emergence, which led to the accordian-fold.

But if anyone has any other thoughts or reasons as to how this may have occurred, I'd love to hear (and be corrected).

Thursday, May 5, 2016

Iris "accordians": What caused it?

Posted by: Alison O'Connor, Larimer County Extension

As I was mulching my front yard a couple weekends ago, I noticed this funny growth pattern on my iris. But it was only on a couple of the leaves....specifically, the third oldest leaf on each plant. Both plants are near my west-facing front door.

Iris "wrinkles"
What do you think caused this? No Googling!

Iris "elastic bands"
In a few days, I'll post (what I think is) the answer. Submit your comments below!