CO-Horts Blog

Wednesday, May 15, 2024

 Western Slope Wildflowers (And a Shrub)

By Mollie Freilicher, Residential Horticulture Specialist, Tri-River Area

The march of native, spring wildflowers continues in the Grand Valley. While not quite the same show we had after last year’s wet winter, we’re still seeing a lot of our favorites, including many that are also at home in our gardens and planted landscapes. 

Here are a few recent finds:

Colorado paper flower (Psilostrophe bakeri). Colorado paper flower is found in western Colorado as well as in Idaho. Its bright yellow flowers, salt tolerance, and ability to thrive in irrigated and non-irrigated conditions makes this member of the Asteraceae family a nice choice for waterwise gardens.

Colorado paper flower (Psilostrophe bakeri)
flowering in Mesa County in May.

Jones’ bluestar (Amsonia jonesii). This member of the Apocynaceae or dogbane family is one of my all-time favorites and I almost missed seeing it flower this year. It is prolific at one site in Grand Junction. Luckily, this past weekend, I was able to catch the very tail-end of its flowering. 

Jones’ bluestar has whitish-blue flowers that are reminiscent of little stars. And the smell! It is definitely worth getting down to give these beauties a sniff. They have a sweet smell, a little like a lilac. This perennial is a Plant Select and is available at nurseries.  Once established Jones’ bluestar does not need any supplemental water.

Jones' bluestar (Amsonia jonesii) in Mesa County in May 2024. 

Jones' bluestar (Amsonia jonesii) in Mesa County in April 2022.

Fremont’s barberry/ Fremont mahonia (Berberis fremontii). This member of the barberry family (Berberidaceae) is at home on pinyon juniper slopes, as well as in our gardens. This evergreen shrub has blue-green prickly leaves throughout the year and abundant yellow flowers in spring that attract a number of different pollinators. 

At the CSU Extension office in Grand Junction, there is a Fremont’s barberry in the cactus garden that has been trained to a single stem (and others in the Ute Learning Garden) that are more shrubby. This is another native with a sweet, almost honey-scented flower.


Fremont's barberry (Berberis fremontii) flowering in
April. This is the single-stem specimen in the cactus garden.


Fremont's barberry (Berberis fremontii) in flower.

Golden sulphur flower (Eriogonum umbellatum var. aureum). So far this year, I have only seen this member of the buckwheat family (Polygonaceae) flowering in front of the CSU Extension office in Grand Junction. There, we have planted Kannah Creek® buckwheat and it is flowering prolifically right now. The flowers are in umbellate inflorescences and attract a ton of pollinators, including lots of flies. The flowers have a distinct odor, though it isn’t one I linger on, like I do with the bluestar or the Fremont’s barberry. The flowers turn more orangey as they mature, adding some additional color to the landscape. In the fall, the leaves turn reddish-purple, providing some great color over the winter. This is a Plant Select plant that was originally collected around the Grand Mesa.

Kannah Creek® Buckwheat flowering in April.

Kannah Creek® Buckwheat and a honey bee.

Seek out these plants as you make your way around the Western Slope or around nurseries and native seed catalogs. 


Ackerfield, J. 2022. Flora of Colorado, 2nd Ed. BRIT: Fort Worth, TX.

Cox, R.W., and J.E. Klett. 1984. Evaluation of Some Indigenous Western Plants for Xeric Landscapes. HortScience 19(6):856-858.

Plant Select,


Thursday, April 18, 2024

Some More Unusual Shrubs to Consider for Colorado

Some More Unusual Shrubs to Consider for Colorado

James E. Klett

Professor Emeritus

The following five shrubs have proven to be tough and reliable options for Colorado Front Range. We have observed their performance over a number of years at the Heritage Arboretum on the Colorado State University Campus. They have shown year after year to be adaptable and very dependable. Most have multiple seasons of interest and ornamental features.


1.       Berberis x ‘Tara’ - Emerald Carousel® Barberry

·         This shrub is a hybrid between B.thunbergia and B.Koreana with deep green summer foliage with persisting red to purplish fall foliage color. It has a rounded growth habit with more arching branches and grows to about 4-5 feet in height and width. It is cold hardy to zone 4 to 6.

·         Sun, xeric

·         Tips and tricks – it has more showy yellow flowers in spring followed by red fruit which can persist after leaf drop. Plant very adaptable to most soil conditions.  

2.       Cornus mas – Cornliancherry Dogwood

·         This dogwood can be grown as a larger shrub or smaller tree maturing to about 15-15 feet in height and width. The yellow flowers before the leaves in March are often the first sign of spring which is followed by red fruit in August that is often sparsely produced due to late spring frost. Hardy to zone 4.

·         Sun, xeric

·         Tips and tricks – the darker green foliage is attractive during the summer with prominent venation and prefers a well-drained soil but is quite pH adaptable.

3.       Foresteria neomexicana - New Mexico Privet

·         This privet is a native Colorado Shrub that can be pruned to a small multi-stem tree by pruning out lower twigs to display light tan to off white bark. It has small yellowish flowers before the leaves in April followed by blue-black fruit on female plants. It can grow 15-18 feet in height and width. Hardy to zone 4 to 7.

·         Sun, xeric

·         Tips and tricks – this is a very drought tolerant shrub and adapts well to well-drained alkaline soil.

4.       Kolkwitzia amabilis (syn. linnaea amabilis) - Beauty Bush

·         Beauty bush is given that name due to the mid-late spring flowers with yellow throats that cover the entire plant for several weeks in late spring. It has a very dense upright arching due to vase shape to fountain like growth habit. The fruit which is a brown universal shaped capsule like fruit that persists into the winter. It is cold hardy to zone 4 to 8.

·         Sun, xeric

·         Tips and tricks – the plant has exfoliating light greyish brown bark that shreds on older stems and is quite disease and pest free. Leaves turn reddish in the fall.

5.       Viburnum burejaeticum ‘P017S’ - Mini Man™ Dwarf Manchurium Viburnum

·       This is a very useful more dwarf shrub that matures to about 4 to 6 feet in height and width with darker green foliage that turns burgundy in the fall. It has white flowers in May that develop into persistent red to black fruit in fall into winter. Hardy zone 4 to 9.

·        Sun, xeric

·    Tips and tricks – Mini Man has good drought tolerance and is a great bird and bee shrub.             

Wednesday, March 13, 2024

Growing Asparagus in the Home Garden

 Written by: Ruth Sens, Weld County Master Gardener

Delicious, fresh asparagus (photo from

The best time to plant asparagus was three years ago, the second best time is now. If you love fresh asparagus and want to try growing it in your home garden, the time is now to get started.

While it can be grown from seed, Asparagus is easiest started from bareroot crowns or crowns already growing in pots. You can buy bareroot crowns at your local garden center now. Choose bareroot crowns that have 8-10 large roots and a one or two healthy looking bud clusters.  Already potted crowns become available later in the growing season. Jersey Giant, Jersey Knight, Purple Passion, Millennium and the Washington series are varieties recommended for our area.

Bareroot asparagus crowns (photo from

Asparagus can produce for 10-15 years so selecting the right place for the bed is important. Choose a sunny (8 hours/day minimum) spot in your garden with well-drained soil where the plants will be able to grow undisturbed. Before planting, soak the crowns in warm water for 2-4 hours. Thoroughly work in four inches of well-composted organic material to a depth of twelve inches before planting. This extra effort will pay off in larger yields.

Now dig a trench that is 6 inches deep and place the asparagus crowns 12-18 inches apart in the trench by carefully spreading the roots out with the bud cluster facing up. Carefully backfill the trench so the asparagus crowns are covered over with just 1-2 inches of soil at this point. When the crowns start growing, slowly cover the shoots with 1-2 inches soil each week until the trench is filled back up and level with the rest of the garden.

Do not harvest any spears for at least the first two years to allow the crowns and roots to develop fully. Some sources suggest waiting three years. At two or three years, you can harvest asparagus spears for 4-6 weeks in early May to mid-June.

Asparagus emerging in spring (photo from

Only harvest spears that are larger than a pencil. Do not over-harvest. Break off the spears or carefully cut with a knife below the soil level being careful to not cut other spears coming up. Then let the ferns grow until fall and stand through winter. Trim back in spring before new spears start appearing.

During the first two years, water 1-2 inches per week. Asparagus is a heavy feeder and benefits from fertilizer (10-16-8) in spring as the growth starts and again mid-summer after the harvest. Mulching around the plants with 2-3 inches of organic material will keep the soil moist, stop weed growth, and protect the plants in winter.  For more information and tips for asparagus planting, visit the CSU Extension Grow & Give website. Want to watch a video on planting? Check it out here.

Now the waiting begins but it will be worth it!

Wednesday, February 21, 2024

A Philospher's Guide to Composting Condoms

Posted by: Derek Lowstuter, Mountain Region Extension

Can a likely made-up story about a famous Greek philosopher help us decide if something should be added to our compost pile?  The answer, much like the question, may surprise you. In a viral story about the Stoic philosopher, Socrates is credited with creating three questions we should ask ourselves before speaking. These “Three Filters” are: Is it True? Is it Good? Is it Necessary?  

These questions can help us understand the potential impact of what we say - before we say it. While this is especially important in an election year, the idea can also help us decide if we should add something to our compost pile. Just because something can be said doesn’t mean that it should be said. Likewise, just because something can be composted doesn’t mean that it should be composted. We can ask ourselves the three questions to help us make those decisions:

Is it True? / Does it decompose?

Is it Good? / Does it improve the compost? And,

Is it Necessary? / Does it need to be composted?

The title of this post wasn’t just to get your attention. I have been asked if all kinds of things can be composted: kitty litter, dryer lint, pet hair, cotton undies, and yes – even latex condoms. Many types of waste are biodegradable and can decompose naturally. However, that alone doesn’t make them good additions to the compost pile.

Let's look at dryer lint as an example of how we can apply the three questions.

Is it True? / Does it decompose? Dryer lint may decompose, depending on the clothes it comes from. Yes, clothes made from natural fibers, such as 100% cotton and wool, produce dryer lint that will decompose in home compost. However, synthetic (plastic) fibers, like polyester or nylon, produce lint full of microplastic pollution that does not decompose.

Is it Good? / Does it improve the compost?  Yes, dryer lint from natural fibers breaks down into organic matter and releases small amounts of plant-available nutrients. However, microplastics in lint from synthetic fibers can fill soil pores and even make their way into the food we grow.    

Is it Necessary? / Does it need to be composted? No, because there are usually other easy ways to dispose of dryer lint. If composting isn’t needed for disposal, then we shouldn’t compost it. Many clothes are made with natural and synthetic fiber blends, which can make it difficult to tell what is in dryer lint. Lint failed the three filters and should not be composted.   

Here are some other examples that could be composted – but should they?

Condoms made with natural latex can be biodegradable but are classified as medical waste, don’t benefit compost when added, and can be easily thrown in the trash. Practice safe compost. 

Wood ash has been used as a mineral fertilizer for thousands of years; however, it can harm compost and soil if overapplied – especially in Colorado’s alkaline soils. 

Animal waste from meat-eaters does decompose but can spread disease and complicate compost management. 

Cooked food waste decomposes quickly, but can attract pests, and promote anaerobic (stinky) compost conditions. 

Diseased plants (ex. tomato blight, powdery mildew) can be composted in active compost that is regularly turned and allowed to go through recommended heating cycles and curing. If you are lazy when it comes to turning your compost *sheepishly raises own hand* it would be safer to take infected plants to a commercial compost facility or create a separate static compost pile that isn’t used on annual crops. Nutrients and beneficial microbes in finished compost have been shown to help plants defend against pests and diseases, but care should be taken when potentially spreading diseases in compost.

To Compost or Not to Compost...

Composting is a simple, powerful tool for turning waste into value for our gardens. When well-managed, compost has been shown to improve soil and plant health, and even increase the nutritional value of produce. The “Three Filters” can help us boost compost benefits and reduce potential issues. 

Remember to ask yourself, 
Is it True? 
Is it Good? 
Is it Necessary?
                                       Happy Composting

Monday, February 5, 2024

It’s spring! (really!)

posted by: John Murgel, Horticulture and Natural Resources Specialist, Douglas County

Ever wonder why Groundhog Day is even a thing? It is one of a broad selection of holidays across cultures and times that mark the mid-point between the winter solstice and the spring equinox. 

These holidays are known as “cross-quarter days,” and you can read more about them here:

 While most modern Americans consider the solstices and equinoxes to be the “first day of” whatever season we’re in, other cultures (rightly, in my opinion) consider those days to be the mid-point of seasons, with the cross-quarter days marking the beginning of seasons.

yellow crocus flowers
These crocus reliably bloom in February.

 Why argue about the first day of seasons on a gardening blog?  Because I am here to tell you, nay to insist to you, that spring is here.  Beneath the foot of snow piled outside the Extension office, spring bulbs are pushing foliage and flowers through the soil.  Hellebores are happily flowering.  Tellingly, the tree buds are swelling prodigiously—aspens and cottonwoods are particularly noticeable because they also smell sweetly musty when they’re expanding.

White hellebore flowers
Hellebores ringing in spring on January 29.


What are some other spring signs to look for?

1.       Bleeding Trees—as deciduous trees begin to move resources from storage in the roots to the limbs, the surging sap will find any leaks in the pipes.  Frost cracks, old pruning cuts, and wounds deliberately inflicted by wildlife (I’m looking at you, squirrels), all provide escape channels for oozing or flowing sugary water.  Maples are famously leaky trees; this is why many people prefer to prune them in the summer.  As temperatures warm and the trees finish growing leaves, the sap flow will slow down and the leaking should cease; hopefully to be stopped before next spring by the trees’ natural wound response.

squirrel in damaged tree
It's hard to say if this squirrel or the damage it caused is more noticeable.


Cool season weeds—cheatgrass, henbit, cheeseweed, and prickly lettuce are examples of the many plants that get a jump on the season by germinating in the fall or winter.  Growing quickly when temperatures allow, they get the competitive edge on their neighbors and if you’re not careful, take over the garden.  Many are annuals, manage them while they’re small and before they set seed!

Cranesbill weed
Cranesbill, Erodium cicutarium, is a common "winter" weed.

3.       Geophytes – plants that hide during the summer heat like tulips, daffodils, and hyacinths are starting to grow underground where most of us won’t see them.  Other plants, though, like snow buttercup (Eranthis hyemalis) and snowdrops (Galanthus nivalis and other species), as their names imply, can already be seen gracing landscapes with their flowers. 

Snowdrops with a honeybee visitor.
This snowdrop is a welcome site for a cold gardener and a questing honeybee alike!


These spring signs, I grant you, are not the ebullient floral displays of May, but they are a sure sign that winter is over, and that should be welcome news for any gardener!

Monday, December 11, 2023

A Few New Vegetable and Flower Varieties for 2024

by Yvette Henson, CSU Extension, San Miguel Basin

It’s that time of year again!  That time when garden seed catalogues are arriving in our mailboxes, either in our post office boxes or in our email inboxes.  Most seed companies highlight new introductions for the year.  I recently attended a webinar hosted by a well-known seed company all about their veggie introductions for 2024 and so I thought it would be fun to write about some of the new varieties I have seen in catalogs that I am thinking about growing in 2024.  As a CSU Extension employee, I want to say that I am not recommending certain seed companies or varieties over others.  There are too many seed companies and too many new listings for me to cover in this blog.  Do your own research with your own growing goals, your own specific growing conditions, and your favorite seed companies in mind.  Try something new.

A local seed company that I get a lot of seeds from is High Desert Seeds.  Their seeds are all grown regionally.  I have grown a couple of seed crops for her myself.  This year, I want to try her ‘Blue Star’ mustard. I want to use it like a southern stewing green (my hubby’s request) but it can also be used young in salad mixes.  In the south, they grow mustard greens in the winter months, but I will have to grow mine in spring and fall.

Photo credit High Desert Seed

Johnny’s Seeds are popular with small farmers and gardeners.  They have many talented breeders on staff.  Each year, I like to grow something I haven’t grown before and this year I am planning on growing a variety of Asian greens.  I would like to grow two of their new introductions in the Asian green category: ‘Haku’(F1) Chinese cabbage and  ‘Green River’(F1) komatsuna green.  They are also offering what they claim is the first white Romanesco cauliflower called ‘Whitaker’(F1).  Baker Creek also offers a white spiraled cauliflower that is open pollinated called ‘De Jesi’.  The standard Romanesco has the equally beautiful and tasty chartreuse green spirals.  White is more unique. While I will give one of the white ones and a green one another try, I have found cauliflowers difficult to grow, especially the beautifully fractalled Romanesco varieties. 

'Haku' Chinese cabbage
Photo credit Johnny's Seeds

'Green River' Asian green
photo credit Johnny's Seeds

'Whitaker' romanesco cauliflower
photo credit Johnny's Seeds

There is a cost for the Whole Seed Catalog from Baker Creek but it may be worth it to you because it contains interesting articles with history, growing conditions and recipes for a select number of crops.  The regular printed catalog is free, and they have a website where you can find all they offer.  Most of their seeds are open pollinated so it makes it easier to save your own seeds!  In this year’s Whole Seed catalog, one of the featured plants is Couve Fronchuda, a Portuguese semi-heading kale, Brassica oleraceae var. viridis.  It is more closely related to sea kale than to the kale we generally think of.  It is traditionally used in soup.

photo credit Baker Creek Seeds (Rare Seeds)

When we go visit our grandsons in California, I often go to a local health food store.  There they have a seed rack for Redwood Seed Company.  I usually buy 1 or two packs of seeds and have had success with them.  This year they are offering Japanese indigo, Persicaria tinctoria, a dye plant.  I live at 8,200’ with cool nights but I think it is worth a try since it is the leaves that produce the dye, and it is supposed to mature in 80 days.  It can also be started early indoors and planted out when it’s warm enough.  This may give it a jump on the season.

Photo credit Redwood Seeds

Floret Flowers is a cut flower/seed business that has gotten into breeding some lovely flowers in atypical colors.  They have their own lines of celosias, dahlias, and zinnias.  I want to try growing their ‘Limonata’ celosia.  It is another warm season variety that may be a bit difficult to mature in my garden.  I will start them early and grow them outdoors as well as in my high tunnel greenhouse. 

photo credit Floret Flowers

Check out this beautiful ‘Mission Giant Orange’ marigold introduced for 2024, exclusively by Burpee Seed company!

Photo credit Burpee Seeds

I would be curious to know what you are planning on growing in the coming season.  Be sure to check out all the new introductions in the catalogs, both in print and online!

Wednesday, October 25, 2023

Ripening Tomatoes Indoors

by Denyse Schrenker, CSU Extension, Eagle County

The temperatures are consistently below freezing at my house and I am ready to put my gardening tools up for the season. Now I need to decide what to do with all of my unripe tomatoes that have been stuck in purgatory for most of October; not progressing under their frost blankets but also not dying. I can only handle so many fried green tomatoes and green tomato relish and salsa so I sort my tomatoes into those that will ripen off the vine and those that will not.

Some of the green tomatoes I separated for relish.

Tomatoes that are starting to develop a pink blush will ripen off the vine without any loss of flavor; this is called the breaker stage. Tomatoes that are a shiny green and have a white to light green star shape on the blossom end of the fruit have reached the mature green stage. These fruits will ripen off the vine but their flavor will not fully develop - a small sacrifice I am willing to make to eat fresh garden tomatoes well into November. Tomatoes that are a more matte green have not reached the mature green stage and will not ripen off the vine, these tomatoes can be used for green tomato recipes.

Tomato starting to develop blush color.

Once I have separated out the tomatoes I want to ripen, I remove any stems and wash and air dry the fruit on a clean paper towel out of direct sunlight. The dry tomatoes are then placed in layers 1-2 tomatoes deep in a covered box or a container with newspaper or cardboard covering them. I keep them in a dark cool location out of direct sunlight to ripen. Store the tomatoes at a temperature between 70°F and 55°F. Tomatoes stored closer to 70°F will ripen in a couple of weeks and tomatoes stored closer to 55°F will ripen in about a month. Tomatoes ripened below 50°F will be bland.

Washed, dried and ready to store for ripening.

Humidity can cause issues when ripening tomatoes indoors. Too much humidity causes the fruit to mold and too little humidity causes the fruit to shrivel. I typically have more trouble with too little humidity. To help increase the humidity, the tomatoes can be placed in a strainer or blanching pan and then placed in a covered container with water at the bottom. Make sure the tomatoes are not touching the water though. I check the tomatoes every couple of days and remove tomatoes that are ripe or nearly ripe. If I want the tomatoes to ripen more quickly I will add a banana or one or two red tomatoes to the green tomatoes.

Ripening tomatoes indoors does not need to be reserved for last ditch end of the season efforts! I try to pick most of my tomatoes when they develop that light blush color. I find that I get better yields harvesting them at this stage and then ripening indoors because I do not lose as many tomatoes to sunscald, critters, or simply missing them before they become over ripe. It may be the end of the gardening season but I am looking forward to having tomatoes all through the fall!

PlantTalk: Ripening Tomatoes Indoors