Wednesday, June 22, 2016

Hort Peeves: When you have to pray after you spray

Posted by: Alison O'Connor, Larimer County Extension

Though she will yell at me for posting this, I'm going to use my mom as an example of this hort peeve. Sorry mom...

When talking to mom a few weeks ago, she asked me, "Hey Al. I want to kill some weeds in my lawn. What do I use?" I advised her that a lawn weed control product is best (after talking about why the weeds were in the lawn). There was a pause and then she said, "Shoot. I used the wrong thing." When pressed, she admitted she used glyphosate (Roundup). And then with a bit of panic in her voice, "Did I kill the lawn?"

One thing that should be noted is that she asked me after she sprayed and not before. Mom!
No, this is not my mom's lawn. This was in Broomfield, Colo.
But I would hazard a guess that most of us have been in this situation before, thus praying after spraying. I have.

Here's your advice for the day: Read the label first. Then think about the product and what the label says. And then read the label again if you have questions. And if you're still unsure, contact the company that makes the product or call your local Extension office. It's very hard to un-do chemical damage. Fellow hortie, Curtis Utley, recently blogged about types of herbicides and their damage.

For some reason, once I started looking for chemical damage in landscapes...especially "Oops I used Roundup", it wasn't hard to find. Lawns are probably the easiest thing to spot.
As seen in Loveland; likely glyphosate damage.
Whatever your opinion is on Roundup, it is commonly used (and misused) in landscapes by professionals and homeowners. So what can you do if you accidentally use the wrong product in the wrong place? Well, it depends on the chemical. If it's just glyphosate and you just sprayed it, try to wash it off. If the product has dried on leaf tissue, like the lawn, you can mow the lawn to about an inch to remove the foliage. BUT not all Roundup is the same (refer to Tony Koski's blog on this). If you used one of the extended control products that contains imazapic or imazapyr, watering can make things worse.

Mistakes can be made and sometimes the damage is significant and costly. So be smart, read the label and can save you a lot of angst. And prayer.

As seen in Wellington, Colo.; a misapplication of a broadleaf herbicide at a park.

Tuesday, June 14, 2016

Help Slow the Spread of Emerald Ash Borer

By Carol O'Meara, Boulder County Extension

In the two seasons since detection of the Emerald Ash Borer in Boulder, experts have learned that it’s very difficult to find.  The Colorado EAB Response Team, arborists, and foresters have been looking high and low throughout the Front Range, into tree canopies and on the ground at firewood, trying to find the destructive pest.  For a time, the only place that bug was detected was in the city of Boulder.

But that changed last Monday, June 6, when Bodhi Tree Care Arborist James Young saw the classic symptoms of the Green Menace:  D-shaped exit holes and serpentine galleries just under the bark on an ailing ash tree in Longmont.  He also found one of the bugs half in, half out of the ash, killed as it was emerging from the branch. 
Young notified Ken Wicklund, City of Longmont Forester, who went to inspect the tree.   In the warmth of the day, Emerald Ash Borer adults – half-inch long, metallic green beetles – were flying around the tree.  Wicklund contacted the Colorado Department of Agriculture for confirmation identification, which, sadly, was positive.

At the same time the insect was found in a new Colorado community, our neighbors in Nebraska announced the first detection of the pest, making their state the 26th to have the tree killer.  The speed of the spread – to 26 states since it’s detection in Michigan in 2002, killing hundreds of millions of ash – causes any tree lover to weep in dismay.
As you ponder the decimation of a native North American tree, consider also that complicit in this is humans.  The insect arrived here because humans brought it over from its native Asia.  It was by accident but, like opening Pandora’s Box, the damage was done. 

The insect doesn’t naturally spread more than about 1-and-a-half miles per season; for it to leap across the Great Plains or even across our county took humans, moving it in firewood, nursery stock, or shipping pallets.  Once infested wood arrived, the insects ventured out into surrounding areas, attacking ash trees.  By the time the bug is detected it can be miles away from the original source of the infestation.
This is why Boulder County is quarantined; the EAB Response team is trying to slow the spread.  No firewood or any ash wood can be taken out of the quarantine.  It will take all of us to do this.

Owners of ash trees near or within the detection sites of Boulder and Longmont should make a plan for what they want to do for their ash.  Protection with pesticides, removal, or replacements with saplings of a different type of tree is a personal decision each tree owner should weigh, because the Emerald Ash Borer kills trees in a scant handful of years.  The Boulder County EAB webpage offers information on all aspects of what you need to consider (
To aid in your decision, the Colorado State Forest Service has a Decision Guide that walks you through the process (   Be sure to assess the health of the ash when considering protecting it; not all trees are healthy enough to save. 

For the most accurate tree health assessment, hire a pro.  Certified Arborists are trained to look for symptoms of EAB and many other pests, be they insects, disease, or environmental problems.  They can climb the tree to take a close look at it.  Find a Certified Arborist through the International Society of Arboriculture (ISA) or look for an accredited company by the Tree Care Industry Association (TCIA).
And don’t move firewood or ash wood around.  This will help slow the spread of the Emerald Ash Borer.

Monday, June 13, 2016

It’s Ascochyta Time

Tony Koski, Extension Turf Specialist

Ascochyta in a Greeley lawn. The green spot
just next to the sidewalk is where a sprinkler
head is located; others are about 30 feet away
in both directions. Pressure problem?
The calls and emails are coming in about beautiful lawns turning ugly almost overnight. This seems to be pretty much an annual happening throughout Colorado in the late spring. When we have wet, cool springs and move into hot, dry summer conditions without much of a transition, massive outbreaks of brown, dead-looking turf can be seen everywhere.

More Ascochyta! The green spot next to the
sidewalk is where there is an irrigation head.
Another head is about 36 feet away, just left of
the tree at the top of this photo. What could
be causing such poor irrigation coverage?
See the next photo for the answer!
Ascochyta leaf blight, though rarely a fatal turf disease, is a darn ugly one. When this disease occurs, it can almost always be connected with an irrigation problem of some sort – not watering at all (“It just rained last week. You mean I have to begin watering already?”), not applying enough water, and – most often – poor coverage due to some sort of irrigation malfunction. Broken heads, heads that have sunken, heads that are blocked by overgrown plants on the borders of lawns, poor system design (which results in poor coverage), pressure problems that prevent head-to-head coverage - and the list goes on. Just because you see water coming out of your heads when you turn your system on in the spring doesn’t mean all is well with your irrigation system.

The large green spot next
to the tree and utility box
suggests a large system
leak - enough to cause a
severe pressure problem for
the rest of the heads on that
station - so green spots
around every head on that
When you experience this disease in your lawn, believe me – IT’S BECAUSE OF WATER (shouting was intentional :) ). Overseeding, fertilizing, applying fungicides, etc. WON’T fix the problem. You won’t get turf recovery until the irrigation problem is solved – or unless you get a number of well-timed, soaking rains. But the problem will show up again when the rain stops.

Once you have corrected the cause of the Ascochyta outbreak (corrected the irrigation problem), avoid overcompensating with water in an attempt to hasten recovery. Irrigate to maintain a moist soil, but not soggy, saturated turf. Too much water will delay recovery and perhaps lead to other disease problems. Depending on severity and turf species, recovery can take 2-4 weeks.

One more thing: the fungus causing this disease isn’t spread by mowers or other turf care equipment – so your lawn care professional did not bring this disease to your lawn.

Read more about Ascochyta in some of our past blogs:

Monday, June 6, 2016

Easy native plant combinations for any yard

 By Irene Shonle, CSU Extension in Gilpin County

Native plants make a wonderful addition to the landscape.  They are water-wise and promote pollinators.  Here are a couple of easy combinations of native plants for each season with impactful colors. These are adaptable for most places around the state.

In spring, pairing blue mist penstemon (Penstemon virens) and wallflower (Erysimum capitatum) makes a bright show that captivates smaller bumblebees and butterflies.

Blue mist penstemon sings in contrast with the oranges of wallflower
Later in the summer, you can’t beat the impact of Rocky Mountain Penstemon (Penstemon strictus) and blanketflower (Gaillardia aristata).  This dynamic duo will bring in butterflies, larger bumblebees and butterflies.
Yellow blanket flower and blue Rocky Mountain penstemon are mid-summer dazzlers

As fall takes over, the red fall leaves of golden currant (Ribes aureum) are eyecatching against the foil of Big Western Sage (Artemisia tridentata).
The fall red of golden currant looks spectacular against the gray-green of Big Western Sage
I would also like to draw people’s attention to the multitude of classes and field sessions on native plants happening around the state all summer.  

The Native Plant Master Program has many field classes of varying lengths and levels – to find a class, go here:

The Colorado Native Plant Society also has a great line-up:

CoNPS Backyard Phenology: How to be a Citizen Scientist in Your Own Backyard
Thursday, June 9, 2016, 6-8pm at the Denver Botanic Gardens

CoNPS 40th Anniversary Celebration
Friday, June 10, 2016, 5pm at the Denver Audubon Nature Center

CoNPS Field Trip (Metro-Denver) Golden Gate Canyon State Park
Saturday, June 11, 2016, 8am-12pm near Golden, CO

CoNPS Field Trip (Northern) Eastern Prairie Ranchlands Flora
Saturday, June 11 and Sunday, June 12, 2016, near Wray, CO

CoNPS Field Trip (Southeast) Elk Park on Pikes Peak
Saturday, June 18, 2016, meet at 8am, Elk Park Trailhead near Cascade, CO

CoNPS Field Trip (Metro-Denver) Hayden/Green Mountain Park
Tuesday, June 21, 2016, 8am-12noon in Lakewood, CO

CoNPS Field Trip (Northern) Well Gulch Trail in Lory State Park
Wednesday, June 22, 2016, 2-6:30pm near Fort Collins, CO

CoNPS Field Trip (Southeast) Cottonwood Pass, Sawatch Range
Saturday, June 25, 2016, 9:30am top of Cottonwood Pass

CoNPS Field Trip (Metro-Denver) Staunton State Park
Wednesday, June 29, 2016, 9am-12noon, at Staunton State Park

CoNPS Rare Plant Seed Scouts Field Workshop
Saturday, July 9, 2016 in Canon City, CO

CoNPS Field Trip (Northern) Elkhorn Creek Noxious Weed Project
Saturday, July 9, 2016, 8am-4pm at Red Feather Lakes

CoNPS Field Trip (Southwest) Cunningham Gulch & lower Highland Mary Trail
Saturday, July 9, 2016, 8am-4pm, meet at Animas City Park in Durango, CO

CoNPS Field Trip (Southeast) The Crags: Birds and Botany in Pike National Forest
Saturday, July 9, 2016, 9am-1pm, near Woodland Park, CO

CoNPS Field Trip (Northern) Elkhorn Creek Weed Mitigation #1
Saturday, July 9, 2016, 8am-4pm, at the Red Feather Lakes Area

CoNPS Field Trip (Metro-Denver) High Creek Fen
Sunday, July 10, 2016, 7am-5pm, High Creek Fen, South Park, CO

CoNPS Field Trip (Gore) Peak 7 Field Trip
Saturday, July 16, 2016, 9am-5pm in Breckenridge, CO

CoNPS Field Trip (Southeast) Buffalo Creek
Saturday, July 17, 2016, meet at 8:30am-3pm Starsmore Discovery Center Colorado Springs, CO

CoNPS Field Trip (Northern) Peak 7 Treasures in Ten-Mile Range
Saturday, July 17, 2016, 9am-5pm Breckenridge, CO

CoNPS Field Trip (Metro-Denver) Hoosier Pass - West Side
Thursday, July 21, 2016, 9am-5pm in Breckenridge, CO

CoNPS Field Trip (Metro-Denver) Silver Dollar Lake
Saturday, July 23, 2016, 6:30am-3pm Silver Dollar Lake off Guanella Pass Road above Georgetown

CoNPS Field Trip (Metro-Denver): Shelf Lake
Saturday, July, 30, 2016, 6:30am-6pm, Shelf Lake Trail

CoNPS Field Trip (Northern) Intriguing Vegetation of Middle Bald Mountain
Wednesday, August 3, 2016, 8am-5pm, southwest of Red Feather Lakes

CoNPS Field Trip (Southeast) Turquoise Lake on Saturday; Independence Pass on Sunday
Saturday, August 6 and Sunday, August 7,
Turquoise Lake, Leadville, CO

CoNPS Field Trip (Southwest) Top of Lizard Head Pass (10,225 ft)
Saturday, August, 6, 2016, 8am-4pm near Telluride, CO

CoNPS Field Trip (Metro-Denver) Shrine Ridge Trail #2016
Wednesday, August 11, 2016, 8:30am-2:30pm, Vail Pass

CoNPS Field Trip (Northern) Elkhorn Creek Weed Mitigation #2
Saturday, August 13, 2016, 8am-3pm, near Red Feather Lakes

CoNPS Field Trip (Southwest) Common Lichens in Western San Juan Mountains
Sunday, August 21, 2016, 9am-3pm, meet at Animas City Park in Durango, CO

CoNPS Field Trip (Metro-Denver) Green Mountain Grasses
Saturday, August 27, 2016 9am-12noon by Jessica Smith

CoNPS Field Trip (Northern) Shambhala Mountain Center
Saturday, August 27, 2016, 9am-4pm, Red Feather Lakes, CO

CoNPS Field Trip (Northern) Elkhorn Creek Weed Mitigation #3
Saturday, September 11, 2016, 8am-3pm, near Red Feather Lakes, CO

Thursday, June 2, 2016

Got weeds? Aerial application is not recommended in the big city

By Curtis Utley, Jefferson County Extension

With the fantastic moisture we have received along the Front Range this spring homeowners are seeing weed growth exploding and with cool temperatures many, myself included, have not been puttsing around in the yard pulling the wayward weeds as frequently as in years past. If you are considering tackling your over-gown weeds with chemical herbicides be aware of a few possible pitfalls and read the entire label before purchasing an herbicide and making an application. Label information is provided to consumers to protect you, your yard and the environment. There are selective herbicides that will kill broadleaf weeds growing in your lawn without killing your grass. There are also selective herbicides that can kill the grass growing in your flower or perennial beds without killing your flowers. There are also non-selective herbicides that will kill anything green, and lastly, preemergent herbicides prevent seedling establishment.
Phenoxy herbicide damage to a perennial bed due to over-spray 

The most commonly available weed killers sold to consumers are the phenoxy herbicides.  Common phenoxy herbicides include: 2,4-D, Dicamba, mecoprop-p (MCPP), and MCPA. Phenoxy herbicides are selective herbicides that kill broad-leafed dicotyledonous plants and do not harm grasses and other monocots. Phenoxy herbicides are auxin mimics and cause hormonal changes leading to rapid uncontrolled growth leading to the death of susceptible plants. The herbicide targets the growing points where cell division is rapid. The symptoms of phenoxy herbicide damage include, twisting, curling and rolling of leaf and stem tissues.  A few weed control products containing the auxin mimics are sold  as hose-end products or are permitted to be applied in an aftermarket hose-end sprayer. While this application method is simple and fast I strongly caution against applying herbicides through such a device due to the potential for overspray. Hose-end sprayers can produce variable droplet sizes which can allow for particle drift resulting in unintended consequences. The other potential issue with hose-end sprayer applications is 2,4-D volatilization. If you apply a broadcast application of 2,4-D on a day when temperatures climb above 85 degrees F. the herbicide can become a gas and float on air currents damaging trees and shrubs.
Phenoxy herbicide injury to green ash due to 2,4-D volatilization

Phenoxy herbicide injury to red oak due to 2,4-D volatilization

Herbicide applications are best accomplished by spot spraying individual weeds with a pump up sprayer. You will use less product, saving money, and can safely direct the application to weed leaves. Spot spraying and adjusting your spray nozzle to produce a course spray pattern greatly reduces the risk of over-spray, herbicide drift and volatilization. 
Dandelion dying after a spot spray application of 2,4-D

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 Acieri'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.
Acieri 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 Acieri'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 Acieri, 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 Acieri 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 Acieri's have two cutting shifts. Believe it or not, their harvest season is only two weeks long!

Acieri'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