CO-Horts Blog

Monday, December 30, 2019

2019 "Top Performer" Perennials Announced from CSU Flower Trials

Posted by Jim Klett, Professor, CSU Department of Horticulture and Landscape Architecture

Our three year (2 winter) herbaceous perennial trials at Colorado State University continues to grow each year with 115 new entries for a total for 270 entries. Plants are evaluated for plant vigor, uniformity, floriferousness and tolerance to environmental and biotic stresses. The following six perennials have been awarded the 2019 “Top Performer” perennial designation after performing superiorly for three growing seasons and two winters in our Fort Collins, Colorado trials.

A complete report on the perennials in the trial can be viewed at under Perennial Trials menu.

Millenium Ornamental Onion from Eason Horticulture Resources and Stonehouse Nursery
(Allium hybrid 'ALLMIG1')
This was a definite “show stopper” plant that was described as having an “insane” amount of blooms.  Flowers were a nice shade of pink and were a favorite of many bees and butterflies.  The flowers combined well with a nice compact plant with clean foliage and very uniform growth habit.  Blooming lasted a long time and flowers did not lodge even with overhead irrigation.  It has been reported to grow well even at 8,000’ in the mountains.  Removal of spent blooms can result in some repeat blooming or can be left for winter interest.  Judges were in unanimous agreement to designate it as a winner. 

Kahorie® Scarlet Border Pinks from Dummen Orange

(Dianthus x hybrida Kahorie® 'Scarlet')
Very showy in the spring with a very vibrant color and attractive plants.  Flower color was not a true scarlet but a beautiful shade of hot rose or cherry.  Plants had superior winter hardiness that was consistent over three years and did not die out in the center as did many other Dianthus.  Plants were attractive even when not in bloom with a nice tidy, compact growth habit.

SUMMERIFIC® Cherry Choco Latte Rose Mallow from Walters Gardens, Inc.
(Hibiscus x hybrida 'Cherry Choco Latte'PPAF)
Large, two tone blooms were captivating with a striking combination of pink and white.  It makes a great choice for providing color late in the season.  Plants were relatively low maintenance as the old blooms were self-cleaning.  Foliage had shades of dark red that was maintained throughout the season.   Plants also had a nice growth habit that did not lodge and the mid-size height made a good balance with the flower size.

Lami Dark Purple Spotted Deadnettle from Danziger
(Lamium maculatum 'Dark Purple')
Dark purple flowers combined with dark green foliage and a very uniform growth habit to make a very impressive groundcover.  This versatile plant did not burn in the sun and did well in the shade.   It has also been reported to look great even at 8,000 feet elevation.  Plants have superior vigor and provide a long period of bloom. 

Bandwidth Maiden Grass from Darwin Perennials
(Miscanthus sinensis 'NCMS2B'PP29460)
This is a good selection for today’s smaller gardens and landscapes as the plant maintains a nice uniform growth habit that is only 3-4’ in height.  Plants did not bloom but foliage is very attractive with yellow stripes running across the blade.  The variegated foliage did not revert and was impressive all three seasons.  Flowers are not needed for interest as the yellow and green contrast in the leaves is very showy.

GRANITA® Orange Ice Plant from Plant Select®
(Delosperma ‘PJS02S’)
Bright, iridescent orange flowers blanket the plant creating an impressive show of flower power.  Large flowers bloom over a long period.  Plants make a very attractive ground cover as the beautiful green foliage forms a nice dense mat that tightly hugs the ground.  Vigor is excellent and makes a good spreader.  Cold hardy and well suited for this area. 

Tuesday, December 24, 2019

An Apple Galaxy Close to You: Cosmic Crisp

Posted by: Alison O'Connor, CSU Extension in Larimer County

I think you can find out a lot about a person by looking at their phone's news feed. For me, you'd learn that I read a lot of stories about baking, golf, Taylor Swift, college football, and backyard chickens. Recently I've been inundated with news stories about the hottest apple on the market: Cosmic Crisp.
Cosmic Crisp apples
A couple years ago, my dad sent my brother and me a story about this apple that was going to take over the world. Or at least a portion of the apple market. It was Cosmic Crisp, an introduction from Washington State University and has parents of Honeycrisp and Enterprise--and was first hybridized in 1997. One great attribute to Cosmic Crisp is that it doesn't brown (oxidize) when exposed to air and is more resistant to bruising. Shelf live is several months.

My family loves apples--it was a staple in our gardens from my great grandparents to my dad. It was always a treat to buy a fresh apple in the horticulture building at the Minnesota State Fair. We're also really proud of being Minnesotan and having Honeycrisp, SweeTango, and Zestar as University of Minnesota introductions.
Honeycrisp apples
Cosmic Crisp is a "game changer" and a "once in a generation event". High praise for a fruit. It's also been developed to replace Red Delicious--that mealy, bland apple that you see in school cafeterias. Now THAT is a big deal. My reliable news feed said it would also be hard find the apples this year, because they had a limited supply.

When I was in Oregon a couple weeks ago, I was at Safeway picking up a few things. And there it was. A bin of Cosmic Crisp. I actually yelped out loud. Then I did what any normal human would do--take a selfie by the apples.
First sighting of Cosmic Crisp!
I was super excited. Cosmic Crisp! The apple to replace Red Delicious! The apple that has Honeycrisp in its genes! Juicy, sweet, crisp! I couldn't wait to try it.
First bite with Mom Stoven, hubby Gil, and me
And my first reaction was...underwhelmed. Maybe I was too excited. Maybe I was expecting more. Don't get me wrong--it's a good apple. But after years of anticipation, I was more "meh" than "WOW". But that's just me. My apple taste preference differs from yours. So I decided that a research taste test was necessary--with my co-workers at the Larimer County Extension Office. They were eager to help.

Apple research taste test
I bought three kinds of apples: Cosmic Crisp, Honeycrisp, and Red Delicious. They were cut and labeled with "A", "B", and "C", so it was a blind taste test (people didn't know what apple they were eating, nor did they know the varieties in the study). Participants had a score sheet and rated the apples based on appearance, crunch, flavor, and overall appleness. Rating was on a scale of 1-5, with 5 being excellent. I also asked the testers to write individual comments about each of the apples.
Apple tasting score sheet
The results were interesting! In appearance, Honeycrisp took first place. People liked the look of the apple, calling it "beautiful" and a "great color". Crunch was awarded to Cosmic Crisp, noting the apple had a "powerful, crisp flavor with a firm texture". Flavor was a tie between Cosmic Crisp and Honeycrisp. Finally, overall appleness went to Cosmic Crisp, and one person commented, "it had the ideal apple flavor of tangy and crisp"; another said, "full taste that was tart and sweet".
"A": Cosmic Crisp
"B": Red Delicious
"C": Honeycrisp
For what it's worth, Red Delicious scored at the bottom of all categories. Poor Red Delicious. Its highest ranking was for appearance, as it's your classic red apple, but taste was "watery" and "bland". One participant stated that it was her children's favorite apple, so it has a following.
Red Delicious--looks better than it tastes
Following the taste test, I revealed the apple varieties and shared some background information about the apples. I also talked about price. Cosmic Crisp was $2.99/pound; Red Delicious was 2 for $1; and Honeycrisp was on sale for $1.99/pound. While it wasn't in the research, people did comment that price is a factor in their apple purchases.

Then I asked everyone to pick the apple they would most prefer to eat. It was a 50-50 split of Cosmic Crisp and Honeycrisp. And that's when it came down to personal preference--some liked more sweet, some tart. The good news is that there's an apple for everyone.

When I came to work today, my co-worker was enjoying an apple at her desk for breakfast. It was a Cosmic Crisp☺You can find them in Colorado at King Soopers and Sprouts. I'm sure Safeway and Whole Foods has some too. Try one for yourself and let me know what you think!

Wednesday, December 18, 2019

Bloom Your Extra Bulbs Indoors

By: Sherie Caffey, CSU Extension-Pueblo County Horticulture Agent

Bulbs are so beautiful and give such a pop of color in the spring. Did you buy bulbs this fall that you never got planted? Or maybe you just want to give a new indoor gardening project a try? If so you can try forcing your bulbs to bloom indoors! It’s fun, will bring some winter color to your home, and cure your winter gardening blues. If you don’t have bulbs left over from the fall, you can order some from an online retailer, or see if a local gardening store has any leftover.

Paperwhites are very easy to grow indoors. They don’t need to be refrigerated, and take only about 6 weeks to bloom after planting. Place them in a bulb pan with a couple inches of soil, pointy end up. Then cover them to about half way with more soil, and water them. You can also do this with no soil and just a pan of water. Place the pan in a cool dark room until you see growth, and then move them to a room with light. PlantTalk script #1322 has more information on paperwhites. 


Amaryllis are very popular around the holiday season, and are also pretty easy to grow indoors. They like a small pot, so choose one that is about an inch taller than your bulb and a couple of inches wider. Plant the bulb so that about half of it is sticking out of the soil. Water it once and then not again until you see it starting to grow. Start watering and fertilizing regularly, and you should have blooms soon! Cut the flower stalk off once the blooms fade and keep watering the leaves if you want to have it again next year. See PlantTalk script #1303 for more information on re blooming your Amaryllis.

For other bulbs such as tulips, hyacinths, and crocus, you will need to give them a chilling period before they will bloom. Plant the same variety in one pot so they all have the same chilling times. Place a loose layer of soil in the bottom of a pot. For a 6 inch pot you can usually fit about 6 tulips, 3 hyacinths, or 15 crocus bulbs. The pointy side of the bulb should be facing up. Add more soil so that the bulbs are about half way exposed. Water your bulbs and don’t let the soil become dry from here on out.
Hyacinths in jars

Now your pots will need to move into a dark, cold place for a while. Try an unheated garage, attic, basement, or refrigerator. Don’t let them freeze or dry out. Tulips will need to chill for 14-20 weeks, hyacinths for 10-14 weeks, and crocus for 14-15 weeks. Bring your pots in after they have chilled, and they should bloom within a month. Start them off in a cooler (50-60°F) room at first and then move them a warmer room after a week or so. Read more about forcing bulbs in PlantTalk script #1319!

Some bulbs are easy to bloom inside; some take a little more effort. Either way it will be worth it when you have beautiful blooms in your home during the off season!

Thursday, December 12, 2019

Oh Forest Tree, Oh Forest Tree

Posted by Todd Hagenbuch, Routt County CSU Extension
The holidays are upon us, and for many, with that comes the age-old tradition of putting up a  Christmas tree. One of my favorite family traditions is going with my wife and kids on a nice day or moonlit night and scouring the hillsides for a perfect tree, always excited to have the smell of conifers once again filling our home.
Ready to find that perfect tree
If you’re going to buy a live tree from a local vendor, you have a lot of options to choose from, with size, species, and price all being considerations.  These trees, typically grown on family-owned tree plantations around the country, are part of a sustainable, green industry.
When you go to a tree retailer, make sure to choose a fresh tree. A fresh tree will have a healthy green appearance with few browning needles. Needles should be flexible and not fall off if you run a branch through your hand. Raise the tree a few inches off the ground and drop it on the butt end. Very few green needles should drop off the tree. It is normal for a few inner brown needles to drop off.
If you don’t want to buy a tree at a lot, you might consider going out and cutting your own tree like we do.  The USDA Forest Service sells permits for $10 per tree, and a family can purchase up to five permits.  These can be purchased at your local Forest Service district office.  The Bureau of Land Management typically sells permits for around $5 per tree, and may allow you to cut up to 3 trees.  Check with your local Forest Service or BLM office for details and for permit purchase.  Also, remember that private property is just that: private!  Don’t enter private land unless you have explicit permission to do so.
When we search for the perfect tree, we look for one that is full and of a good height. We also try to make sure that it is a tree growing in among several others and not one that it out by itself. Why? The lone tree will likely survive longer in the forest, while those that are spaced too closely to one another are vulnerable to disease and insect issues in the future. This is an opportunity to not only get a good tree, but help manage the forest as well. A bonus for us is that we typically put our tree against a wall, so finding at tree that is a bit flat on one side since it's growing among others is a plus.
Once you've found that perfect tree, cutting it is easiest as a two-person project. The "cutter downer" usually lies on the ground while the helper holds the bottom limbs up. While the cut is being made, the helper should tug on the side of the tree opposite the cut to ensure that the saw kerf remains open, keeping the saw from binding.
Loaded up and ready to head home!
Before the tree comes inside, cut 1 ½ inches off the bottom of the tree and immediately plunge it into a bucket of water.  Otherwise, sap will seal the bottom of the tree and keep water from entering.  Have your tree stand ready, and work quickly so you can get water back in it right away.  Trees take about 1 quart of water for every inch of diameter of the trunk, so be prepared to water the tree several times each day.  Remember that if it goes dry, the sap can reseal the trunk.  Also, to help keep the tree fresh, keep it away from heat sources and out of direct sunlight.
When the holidays are over, recycle your tree. The resulting mulch will be a great addition to your yard in the spring.
Finally, don’t forget that you can have a real, growing tree in your home as well.  Buying a potted tree and planting in the spring can help keep the holiday spirit alive in your yard for years to come.
Happy holidays! May your days (and tree) be merry and bright!

Monday, December 9, 2019

Make a Holiday Tree from a Tomato Cage

by Amy Lentz, Horticulture Extension Agent - Weld County

That's right! A tree made from a tomato cage! This is a fun and fairly easy holiday craft project that can utilize those extra clippings of holiday greenery.

Here's how:

1. Find a Tomato Cage 
The size is your choice. I used a simple 4' tomato cage, nothing fancy! Turn it upside down and place on a flat surface.

2. Gather Some Real Holiday Greenery 
Luckily, a local hardware store had a bin of free branch clippings that were left over from trimming all the trees sold during the holiday season. I stocked up on some great Noble Fir branches! You will need approximately 8-12 branches depending on their size. Check with your local nurseries, hardware and big box stores for greenery sold as branches, too.

3. Use a Rubber Band
Wrap the rubber band (several times) around the loose ends of the tomato cage. A thick rubber band will be easier to work with. You'll need another rubber band later.

4. Start Weaving in Branches
This is the fun part! Start toward the bottom of the tomato caged and just place branches over the wire in an upside down orientation with the cut branches up and the branch ends toward the base of the tomato cage. You may need to put larger branches on the second rung to keep them at ground level. Once in place, try to bend and weave the branches around the scaffold and side wires of the cage to secure them. You shouldn't need to secure them with ties unless the tree will be in a windy area. If you do need to tie them, you could use small zip ties to secure the branches to the wires.

5. Keep Filling in the Space
Add more branches, working your way toward the top rung of the tomato cage. Starting low and working your way up the tomato cage will layer the evergreen foliage nicely. You may need to cut a few into smaller pieces as you go higher.

6. Fill in the Top
Use a few smaller branches to place around the top of your tomato cage. Use the second rubber band to secure the branches by wrapping it several times around the bundle.

7. Add Some Bling
This is where you get to use your imagination! I used some simple artificial floral sprays with poinsettias, berries and pine cones that I found on sale at the fabric store. I just placed them throughout the tree in a similar upside-down fashion.

8. Top it Off
Add a stocking cap, hat, star, scarf (whatever you can think of) to cover up the exposed branches at the top of the tree. I used a Santa hat with a stiff cone inside to help keep its shape.

In just a few simple steps, now you can create your own holiday tree made from a tomato cage and leftover tree trimmings. Happy Tree Making!

Friday, December 6, 2019

Gifts for the Gardener in Your Life

Post by Mike McNulty, Broomfield Master Gardener

Winter officially begins December 21st, but procrastinating gardeners are not yet thinking about presents. They’re still frantically attacking last-minute chores like clean-up, or wrapping young trees (especially redbuds, maples and fruit trees!). Through the cold and snow, the die-hard gardener will be thinking about the upcoming growing season via seed catalogs and PlantSelect® brochures. If you’re looking for a thoughtful gift for the gardener in your life, consider these garden essentials:

Gardeners are almost universally in need of another pair of gardening gloves by season’s end.  Most gardeners also spend a fair amount of time kneeling in the garden, so a set of knee pads or a kneeling board would be deeply appreciated.
As gardening tools go, pruners may be the most essential.  Look for ergonomic designs, and make sure to choose the right tool for the job. The best pruners for green stems are bypass pruners that act like scissors and reduce plant damage.  For precision jobs like harvesting tomatoes or deadheading flowers, use micro tip pruning snips.  A set of bypass loppers are a good bet for larger stems and limbs, and a pruning saw is useful for almost any trimming of woody plants.

Clockwise from top left:
Pruning saw, Hori Hori knife (garden knife), bypass pruners, micro-tip pruning snips.

A personal favorite with amazing versatility is the garden knife, also called a Hori Hori knife.  Hori Hori means “dig dig” in Japanese, and it’s fun to say!  The notched blade is perfect for weeding; use the serrated edge to cut sod, divide perennials or trim root balls; the smooth edge is great for opening bags of mulch or fertilizer and often has measurements for planting depth.

When in doubt, you can always leave the decision-making to the gardener with a gift certificate from their favorite garden or nursery center. Happy holidays!

Monday, November 25, 2019

BEE Thankful for Pollinators

Posted by: Lisa Mason, Arapahoe County Extension

We have so much to be thankful for this holiday season including the meals we eat. Have you ever wondered how much of the food on our tables is dependent on pollinators? Approximately 1/3rd of our diet is dependent on pollinators, including some of our most nutritious fruits, vegetables, and nuts. Even our meat and dairy industries depend on pollinators because bees pollinate alfalfa and clover, which are food sources for cattle. (Food staples like corn, rice, soybeans, and wheat are either wind-pollinated or self-pollinated.)
Honey bees (Apis mellifera) are important food crop pollinators. Some species of bee flies (Bombyliidae family) can also pollinate crops. Photo: Lisa Mason
As you plan your holiday meals with family and friends, we can think about all the delicious foods we have because of pollinators. Here is a list of common food items and who pollinates them provided by The Pollinator Partnership:
  • Almonds - Honey bees
  • Anise – Honey bees
  • Apples - Honey bees, blue mason orchard bees
  • Apricot – Bees
  • Avocado – Bees, flies, bats
  • Blueberry – Over 115 kinds of bees, including bumblebees, mason bees, mining bees and leafcutter bees
  • Cardamom – Honey bees, solitary bees
  • Cashew – Bees, moths, fruit bats
  • Cherry – Honey bees, Bumblebees, Solitary bees, flies
  • Chocolate – Bees, flies
  • Coconut – Insects, fruit bats
  • Coffee – Stingless bees, other bees, flies
  • Coriander – Honey bees, solitary bees
  • Cranberries – Over 40 bee species
  • Dairy – Dairy cows eat alfalfa pollinated by leaf cutter and honey bees
  • Fig – Over 800 species of fig wasps
  • Grape – Bees
  • Grapefruit – Bees
  • Kiwi fruit – Honey bees, bumblebees, solitary bees
  • Macadamia nuts – Bees, beetles, wasps
  • Mango – Bees, flies, wasps
  • Melon – Bees
  • Nutmeg – Honey bees, birds
  • Peach – Bees
  • Pear – Honey bees, flies, mason bees
  • Peppers – Bumble bees
  • Peppermint – Bees, flies
  • Pumpkin – Squash and gourd bees, bumble bees
  • Raspberry and Blackberry – Bees, flies
  • Strawberry – Bees
  • Sugar cane – Bees, thrips
  • Tea plants – Flies, bees, and other insects
  • Tequila – Bats
  • Tomato – Bumble bees
  • Vanilla – Bees
Note: This list is not comprehensive. Many other crops also require pollination by insects and animals.
Some species of leafcutter bees (Megachile spp.) are important crop pollinators. Photo: Lisa Mason
Now you can quiz your friends and family over the holidays about what foods are dependent on pollinators.  

Have a safe, healthy and happy Thanksgiving!  

Thursday, November 21, 2019

Trials of Indoor Gardening pt.1: spider mites, aphids, and thrips oh my...

Posted by: John Stolzle, Jefferson County Extension
One of the best things about indoor gardening is being surrounded by green foliage during winter. But this also brings a potential for pests to thrive 365 days a year.

The indoor garden remains unaffected by an early season blizzard; fresh produce as of this publication date!
One of the greatest challenges my garden has faced has been a battle against aphids and spider mites. In outdoor environments, natural predators do much to keep populations of pests (like aphids and spider mites) in check. But in the climate-controlled world of an indoor garden or greenhouse pests can reproduce unchecked by predators and lead to imbalanced (aka. out of control!) populations.

Where did they come from?
With a few exceptions, plants which I started from seed have remain unscathed; however, a few plants which were placed next to incoming nursery stock encountered problems.
Damage from inadequate watering and spider mites on a Jalapeño
Case in Point: one poor Jalapeño (photo above) that was started from seed caught a bad case of spider mites from another pepper plant which was purchased from a commercial nursery/greenhouse. Initially things in the garden were great but while I went away on vacation, insects were busy chowing down on my pepper plants. I returned to what you see in the picture.

Some time after this, I purchased a sad looking (#discount) Taro plant. I placed it in the garden, wiped off its leaves and stalks with a damp paper towel, and watched it closely. After some weeks, I began to notice many tiny glistening, sticky spots on its leaves; the spots were honeydew, evidence (waste) left by aphids. I took a closer look (picture below) and saw tiny green insects (aphids) moving around the leaves.

Aphids on a Taro leaf
A lack of patience.
One pepper which had become infested with spider mites appeared to stop growing after treatment. I became frustrated because it hadn’t produced a new leaf over the course of two months! So, I decided to rip out the pepper and use the pot for something else.
Pepper plant after 3 months of growth in an 18cm (7in) diameter pot.
Little had I known that the plant had been developing a very robust root system. Sigh.. a root system that would have been able to support many specialty peppers. On the flip side, now I know the plants are growing and that this container was likely too small for the plant anyway. Recommendations for adequate container sizes can be found here

What can be done... aside from tearing out a plant?
It is important to first know what may be attacking a plant. For example, after looking for some time (phone cameras, magnifying glasses, hand lenses, and microscopes can be helpful!) I observed not only spider mites but also thrips on my pepper plants! These two insects require slightly different management strategies. Note: Information on thrips is linked-to at the end of this post.

Spider mites and aphids lay eggs on plant material and go through a roughly 2-week life cycle (important to know when planning follow-up treatments). A jet of water is often enough to dislodge these pests from many plants. Have a spider plant (‘Chlorophytum comosum’with spider mite webbing between its leaves? - Give it a shower in the sink!

It is easier to battle 10 insects than it is 10,000. Washing a nursery plant upon its arrival can save headaches  by preventing major outbreaks from ever occurring. Note: Not all plants like to have wet leaves. It can be helpful to look up a plant’s general care recommendations.

Insecticide products do exist for treating spider mites, aphids, thrips, and other various plant pests. Insecticidal Soaps with the active ingredient Potassium Salts of Fatty Acids, and Horticulture Oils (e.g. Neem, Cottonseed) can be effective parts of an integrated pest management strategy. It may not seem like it, but Insecticidal Soaps and Horticultural Oils can be harmful to humans and pets and other non-target organisms. Pesticide product labels should always closely be followed and adhered to. Note: when applying an insecticidal soap (active ingredient: 'Potassium Salts of Fatty Acids') any insect not completely wetted (e.g. an aphid hidden in a rolled up leaf) will not be affected.

What I wish I would have known.
  • That placing plants in the shower or sink or (even better!) taking them outdoors prior to treatment can make cleanup a much easier process.
  • Some plants can react poorly to Insecticidal Soap and/or Horticultural Oil treatments. It can be mildly traumatic to see a plant drastically defoliate a day after being treated.
  • Yellow sticky pads can be incredibly effective at managing indoor populations of fungus gnats (sometimes mistakenly referred to as fruit flies).
  • Patience is key (in reference to the pepper I tore out).
For more information on a variety of topics, please see the links, below.

As a fun aside, insects (like 'Lady Bug' and Lacewing larvae) which feed on spider mites, aphids, etc. can be purchase from locations around the USA. Here is a very impressive list of BioControls and example locations from across the US where they can be acquired:

For an introduction to this indoor garden, please see this blog post:

 Best of Luck in all your gardening endeavors! 
- John