CO-Horts Blog

Thursday, June 30, 2016

Cherries, Apricots and Peaches, Oh My!

Fruits of the Grand Valley are abundant this year.  A mild spring with good rain actually gave us cherries and apricots this year.  Depending on who you talk to and where they are located, people will tell you that we only get a cherry crop every 4-10 years due to late frosts.  So cherish those sweet cherries, hopefully we will have lots of them next year, but only Mother Nature knows.  Cherries in our area do require control of the Western Cherry Fruit Fly.  If not controlled, you get little worms in your cherries, not very appetizing.  Here is how to control them.
The apricots due get Coryneum blight, also called shot hole disease because spots form on the leaves and then drop out.  The fruit gets red spots mainly on the upper surface where the rain sits.  Unfortunately, the best time to control this disease is in the fall.  Removal of infected twigs and branches helps too.  Here is our information on this fungal disease.  In the home garden, you can cut out these bad spots in the fruit, but it certainly does not make the fruit saleable.
I did one site visit very early on to a peach orchard that had very early signs of coryneum blight and the grower was able to do some spraying to control it.  Luckily it was only in one low lying corner of the field.  Where plants grow really does make a difference.  A few very early peaches are coming to market now but we will see the bulk of early yummy Palisade peaches hit the market in about two weeks.  Bob Hammon, our Entomologist tells me we will also see Olathe Sweet, Sweet Corn about July 11th.  Can I say again, YUM.  Nothing better than fresh produce.

Back to the peaches.  I am on a Working Group to help find disease controls for Cytosphora which is a fungal disease that has no cure.  We believe many stressors’ contribute to this disease starting with proper planting techniques, insect control, care and maintenance and cleanliness.  A new Plant Pathologist, Jane Stewart, on campus is studying the effects of different fungicides as a control.  Samples are being sent to her from our area.  But we still need to find out the why.  My big point to you, the reader, is that fruit trees are very hard to grow, take a lot of time and responsibility to grow and not spread any pests.  In fact, I would say fruit trees are the highest maintenance plant one can grow. 

Yes, I do have some fruit trees on my property, but luckily my husband also has a horticulture degree so he does most of the insect control, we split the pruning duties, both pick and guess who does most of the canning?  Thou he has gotten into drying.  He dried cherries last weekend.  So in the end, appreciate all the hard work that went into the fresh fruit, support your local growers and a good thank you would go a long way too.  Enjoy.

Susan Carter
CSUE Tri River Area Horticulture Agent

Monday, June 27, 2016

Making Lemons From Lemonade

by Mary Small, CSU Extension
State Master Gardener Coordinator

As you’ve probably guessed, this is not about the cold beverage made from oval yellow fruit. It’s about those not-so-nice things that sometimes happen in the landscape.

I planted a climbing yellow rose (can’t remember the name) in the garden. It performed beautifully for several years. Yes, it had some winter dieback every year as roses do in our climate, but nothing like what happened following the November 2014 polar vortex. That took the whole thing out.
I didn’t get around to digging it up last year and it sprouted from below the graft union.  Since I was going to take the thing out, I just ignored it and I think it ignored me, too!

Unidentified fragrant rose
This spring, before I got around to digging it up, the canes rewarded me with the most beautiful apricot colored, fragrant blossoms! The little garden adjacent to the rose is dreamy with its scent. And to think I almost destroyed it!

Young oak is growing well
We used to have a 10 year old catalpa in our front yard. It looked kind of like a Dr. Seuss tree as the top had been broken out of it. But it provided wonderful, cooling shade. A few years back, an early fall snowstorm broke out so many branches that it finally had to be removed. We replaced it with a small oak tree and complained about the lack of shade.The oak has only been planted for three years, but it has put on more yearly growth than I ever expected. Now that catalpas are blooming, I’m reminded that I don’t have to rake up their flower stalks, leaves and seed pods anymore!
Alison O’Connor, one of our bloggers, lost a large maple in a tornado several years back. But it
gave her the opportunity to plant other trees and plants that she wanted to grow. Just look at the before and after pictures. I think you’ll agree the tree loss was really a net gain.

Spring 2016

Alison also lost her vegetable garden in a severe hail storm. (Are we seeing a pattern here?) She turned the loss into lemonade by planting a cover crop – which improved her soil for the next season.

Smashed tomato after hail
Sometimes those gardening “mishaps” or “missteps” actually turn out better than expected...or planned!

9 weeks later, a cover crop!

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