CO-Horts Blog

Monday, May 27, 2019

Even Beagles Love Mulch

Posted by: Alison O'Connor, Larimer County Extension

If you missed it, fellow hortie John just blogged about the awesomeness of mulch. Truly--it's a great thing for your landscape! This weekend I replenished the wood mulch in a few areas of my landscape...and Maple the Beagle thoroughly enjoyed it.
A little extra fiber in the gut never hurt anyone. And let's be honest--doesn't a fresh layer of mulch make the landscape look pulled together? Plus, it helps conserve moisture, reduces weeds, and adds organic matter. Maple gives mulch two paws up.

Saturday, May 25, 2019

Native Plants at the Confluence of San Miguel and Dolores Rivers, Western Colorado

by Yvette Henson
CSU Extension has a program called Native Plant Master.  Since 2007, our county has participated in this program by offering classes for Native Plant Master Certification as well as offering single, day-long Native Plant Education Classes (field trips).  Our longest running class is held at the confluence of the San Miguel and Dolores Rivers in extreme western Montrose County.  Except for our first course, in 2011, we 've held the class on the 3rd weekend of May.  Holding it on the same general date has allowed us to see slight variability of plants in bloom and bloom times, based on the weather conditions leading up to that season.

Confluence of the San Miguel and Dolores Rivers, 2011, 
Dolores on the left and San Miguel on the right. 
(Photo credit Yvette Henson)
The Confluence class is held all along the River Road from Uravan to Bedrock at about 5,000’ elevation.   This site is high-desert canyon shrub-land and riparian.  Predominant native tree and shrub species are  Utah juniper (Juniperus osteosperma), pinion pine (Pinus edulis), New Mexico privet (Forestiera pubescens), single leaf ash (Fraxinus anomala), service berry (Amelanchier alnifolia), lemonade bush sumac (Rhus triolobata), cliff fendler-bush (Fendlera rupicola), Mormon tea (Ephedra viridis), fourwing salt bush (Atriplex canescens), greasewood (Sarcobatus vermiculatus), sage (Artemisia spp.), river birch (Betula glandulosa) and coyote willow (Salix exigua) and others.  Some of the more showy flowering plants we might see in our class are Yuccas, 4 species of cactus, at least 3 species of Penstemon, 2 species of Phlox, many Astragalus species, several Oenothera species, Erigeron species,  globe mallows (Sphaeralcea spp.), prince's plume (Stanleya pinnata), Indian paintbrush (Castilleja scabrida) blanket flower (Gaillardia pinnatifida), and many, many more.  There are so many interesting plants to be found along the river road!

Along the River Road (Photo credit Yvette Henson)
In this blog I will highlight just a few of the most interesting native plants (at least to me).  The first is single leaf ash, Fraxinus anomala. The specific epithet refers to the plant being an anomaly because it has a simple leaf instead of a compound leaf like all the other ashes.   It is a small tree with shiny golden-green leaves and non-descript flowers that are followed by somewhat showy samaras.  The blooms have a lovely fragrance, reminiscent of sweet olive (Osmanthus fragrans), a plant in the same family (Oleaceae) that is grown in the Southeastern US.  

Single leaf ash in bloom (Photo credit Yvette Henson)
Single leaf ash samaras (Photo credit Al Schneider,
During our first class in 2011 we saw an interesting plant in the pea family (Fabaceae) that we had never seen before.  It turned out to be a rare plant found only in Delta, Mesa and Montrose counties.  It is called Grand Junction Milk vetch, Astragalus linifolius.   This is a beautiful, upright-mounding herbaceous plant with white flowers that have a purple spot on the tip of the keel.  Previous years dead stems persist at the base of the plant.  We look forward to seeing this plant every year and this year it was in full bloom on the day of our class.
Astragalus linifolius, Confluence Native Plant Class, May 17, 2019
(Photo credit Yvette Henson)
Another rare plant that is a close to my heart is alcove or mancos columbine, Aquilegia micrantha.  It grows in cool, moist cracks of the red sandstone of the washes and side canyon walls.  We’ve only seen it in one area but a student in this year’s class who drives that road frequently has seen it along the road, again in cracks in the sandstone.  Our population has delicate looking blooms in pale yellow, some with more red on the spurs than others.  Other populations can be whitish.  The leaves are thick and glossy and sticky to the touch.  I couldn’t find my photos of this plant so I used one from Al Schneider, swcoloradowildflowers.  

A beautiful site we saw this year was a ‘super bloom’ of Heliotrope phacelia, Phacelia crenulata.  It covered a large expanse of hillside along one portion of the River Road.  These photos were taken by a class member, Bill Grimes, on the day of our class, May 17, 2019.   The first photo is a snap shot of the expansive bloom covering the hillside  (its difficult to get the actual effect!) and the second is a close up of a single plant. 

As a side note, for western Colorado native plants, I highly recommend for the beautiful pictures and identification information.  I believe Al is using names from the Flora of North America.  The names of plants in this blog are from the Flora of Colorado by Jennifer Ackerfield.

Monday, May 20, 2019

Oh Look at that, I Stained My Shirt

By Curtis Utley, Jackson County Extension
For our school’s Earth Day celebration this year I was asked to provide a t-shirt for the 4th-8th graders. Being interested in STEAM education I thought to myself “Hmm, instead of giving the students a shirt I will provide the necessary materials to make a shirt”.
Application of blueberry blue with rubber mallet.

For thousands of years mankind has used naturally occurring materials to dye the clothing worn. Some of the materials are earth minerals but many of the dyes used are derived from plants. Not all plant-based dyes are very stable, but stability can be increased by pre-treating the cloth with a mordant. I pre-treated the t-shirts with potassium aluminum sulfate otherwise known as Alum, you know, that stuff you can use to make your canned pickles crisp.

The dyes we used were mainly fruit and vegetable based including blueberries, cranberries, carrots, grape juice concentrate, tomato juice, and coffee.
Application of Cranberry gray.

Even in nature colors are chemical, but everything is chemical right? yellow, orange and red are derived from the plant’s production of carotenoids. As dyes, carotenoids are best mixed with an oil carrier to help fix the color. Purple, blue, and pinks are derived from anthocyanins. As dyes, anthocyanins can be mixed with water to create a liquid.
Application of cherry red with rubber mallet. 

The best part of this project from the students’ perspective was the way in which we applied the colors to the t-shirts. Simple and brutish I let the students smash the fruit into the fabric with rubber mallets or paint their shirts with the liquid concentrates.

Isn’t is fun when expressionist art meets nature and science?
Finished product after laundering. 

Wednesday, May 15, 2019

They're Baaaaaaack! Voles.

Posted by Alison O'Connor, Larimer County Extension be honest...the voles may not be back so much as they never really left. We've blogged about voles before. Tony blogged about them in the lawn, and Irene blogged about them too--twice!
Meadow vole. Kinda cute, but crazy destructive.
Voles are small, mouse-like creatures with short, stubby tails. They are sometimes called meadow mice and we have eight (8!) species that live in Colorado. They are most active at night, but you will see them during the day--and like mice, they will run frantically when disturbed. You'll see damage in the lawn with their tunnels and also on landscape plants that they chew.
Vole tracks in the lawn.
The good news is that voles are a boom and bust species. We'll see huge populations one year, and the next season they will crash. Our state veterinarian once told me that some species of voles do their part to help control populations--male voles will become sterile when he has too many siblings. Fascinating.

They do have natural predators, like birds of prey, coyotes, and fox, but there seems to be so many voles and too few predators. Plus, voles love our landscapes where there aren't a lot of predators and it's a cozy, safe place to take residence. And that's where they are a problem. They like to live in tall grassy areas, and also in landscape beds--especially those with mulch and landscape fabric.
Voles love to live under landscape fabric, because it's safe from predators.
I visited a friend's landscape in Berthoud recently and over the winter, when voles were actively feeding on her plants, she ended up losing most of her roses, some lavender, and a few perennials. She literally just pulled the plants from the ground. Voles love to chew at the base of many ornamentals and fruit trees, girdling them. In the case of my friend, they chewed so much, the plants just broke off at the base.
All of her roses were killed this winter.
Girdled rose chewed by voles.
It's especially upsetting, since we all know that landscape plants are an investment. Losing this many can affect the budget--plus, the plants were mature and her landscape was beautiful last summer. The one that really got me was her fantastic dwarf blue spruce...which still looks perfectly healthy, but it's only a matter of time before it goes into decline. When you have the entire base of the tree that's been girdled, there's no way for the tree can move water and nutrients up and down the tree, since the xylem were damaged.
What looks like a perfectly healthy dwarf blue spruce...
The base of the spruce was girdled completely, approximately 2-3" off the ground.
Another sign of voles is damage to junipers. Voles love junipers--it must be their form of chocolate. I received an email earlier this week from a client who wanted to know what caused the browning in his junipers. I suspect it's voles and asked him for confirmation.
Potential vole damage in junipers.
Trace back the branches to the base and look for chewing where those branches attach to the shrub. The only remedy in this situation would be to individually (and painstakingly) cut out each damaged branch. Oh, and control the vole population.

What works best are unbaited mouse traps, placed end-to-end, near areas of activity and cover with a piece of gutter. Voles aren't smart animals and they will run, with free abandon, throughout the landscape. If you place the traps near active tunnels or near where they are actively feeding, you'll snap them, just like mice. Traps need to be checked and reset daily. There's lot of recommendations of baits that you can use (including Juicy Fruit gum!?!) but voles aren't motivated by baits--they are herbivores. Unbaited is best. They also don't seem to eat poison baits, which poses other potential issues for non-target animals.
Unbaited mouse traps, placed end-to-end, near active voles.
Cover the traps with a piece of gutter. Voles like the protection and shelter of above canopy, which is why they live under landscape fabric or in tall grass. They are less noticeable to predators.
Another tool that shows promise is using an organic fertilizer called Milorganite. This product has been around for decades and it's composted sewage sludge from the good people of Milwaukee, Wisconsin. (Don't worry--it's been heat-treated to 1600 degrees and poses no harm to humans.) Voles and other mammals, like rabbits, groundhogs, and even deer, don't like the smell.

Apply this fertilizer to any area of the landscape, including the lawn, landscape beds, or vegetable beds, at a rate of 15-20 pounds of product per 1,000 square feet. The 40 pound bag will cover about 2,000 square feet total and runs about $20. Now, this product is a repellent. It will make the voles go elsewhere, so using it in the entire landscape may not be practical, but focusing on active vole areas can work (or where you have rabbit damage). Once you apply the product, water it in. You'll notice the "earthy odor" for a day or so, but voles and rabbits will notice it for perhaps three weeks. Plan on applying it every month. It's not sold at most box stores, so check farm and ranch stores, or local hardware stores. As a side note, it's an excellent fertilizer, so you can use this to fertilize your lawn too.
Milorganite has been found to work to repel voles and rabbits in the landscape.
I should also point out that Extension doesn't usually list specific products, but Milorganite was tested in several research studies at the University of Nebraska, which is why we're recommending it. We'd love to hear if it works for you--be sure to let us know!

It's always something, isn't it? If it's not voles, it's late spring frosts. Or hail. Life as a gardener is truly a test of patience.

Friday, May 10, 2019

It's Tool Time!!

Posted by: Deryn Davidson, Boulder County Extension

It's no secret that this spring has been slow to get going and now in my area we've had another stall-out with a week of rainy, cool weather. So, what is an eager gardener to do while they have to wait for plants to wake up and the weather to clear?? Make sure their tools are in good working order so they can spring into action when the conditions allow!!

Just like the gardener, garden tools work hard. They are left out in the elements, dragged through the dirt, hung up wet, shoved in buckets, lost under garden benches, you name it! They get abused. So, if you set aside a little time to treat them right, they will serve you well for years to come.

Now, some might say this is a task for the END of the season when you're cleaning up and putting your garden to bed. I'm sure some people do clean and sharpen everything then, but I know not everyone does. In fact, I know that a lot of people don't do this on any regular schedule at all. Well, like any craft or tradesperson, a gardener's tools are an important part of their work so it's a good practice to make sure your loppers, pruners, shovels, rakes, tiller, mower, etc. are all set and ready to go for a successful season.

Image result for dirty prunersgarden tool maintenance, tools

Pruners and loppers:
Clean your pruners and loppers by taking them apart (if possible) and giving them a good scrub in soapy water. Steel wool will help remove any rust that might have built up. It's not a bad idea to soak them in a dilute bleach and water solution (1:10) to sanitize and then rinse and dry. Once they are thoroughly dry, rub them with boiled linseed oil to give them a protective layer from oxygen and moisture and then reassemble.

Sharpen your tools so that they are easier to use and they make clean cuts. You don't want to risk damaging branches by tearing or ripping them because your pruners didn't quite do the job. There are sharpening stones you can get for your pruners or you can take them to a local hardware store and they will often sharpen them for you. Farmer's Markets often have vendors that will sharper knives and tools so you can look for that option too.

Throughout the season, after you use your pruners and loppers, give them a quick clean. Get the sap, dirt and grime off and store them inside and they will stay in good shape throughout the season.

Shovels, rakes and hoes:
Give these a good clean by knocking, brushing or rinsing off any dirt that might still be stuck on them from the previous year. Shovels can be sharpened so that they are easier to dig with. You're not looking for razor sharp with shovels, but having them "just sharp enough" will make digging those new garden beds and transplanting and dividing much easier. They will also benefit from boiled linseed oil once they've been cleaned and dried thoroughly. 

If your shovels, rakes and hoes have wooden handles it's a good idea to check on those too. Over time they may start to crack, splinter and even break in two. If this happens, you can buy replacement handles and attach them to the head of the tool, rather than buying a whole new tool. For general care and maintenance you again want to give handles a clean, let them dry and rub them with linseed oil.

Tools with motors (mowers, tillers, etc.)
For these tools, you can certainly take them to a small engine shop and get a tune up, or you can check out the operator's manual for details on how to do it yourself. This will generally include changing out the oil, filling with fresh gasoline, changing an air filter, change spark plugs, and sharpen the blades.

Horizontal shot of dirty lawnmower in overgrown grass Stock Photo - 12887206
Now that you have everything in tiptop shape and are ready for the season to really start, remember that it is best to clean as you go. That way, many months from now when the leaves start to change and there is a chill in the air, your tool maintenance won't be such a big job and you can knock it out at the end of the season!! I should say, big kudos to those of you who do your tool maintenance early and often!!! To the rest of us, now is a great time too tackle it. Happy gardening!!!

Monday, May 6, 2019

Most Insects are Beneficial!

Posted by Abi Saeed, Garfield County Extension

Did you know that 99% of all insects are either harmless or benefit us in some way?

Beneficial insects fall into 3 main categories:
  • Predators / Parasitoids: Insects that feed on other "critters" providing an important source of pest control in nature. This group is responsible for keeping pest populations balanced, otherwise herbivorous insects could easily deplete our flora.
This Robber Fly (Family: Asilidae) is an excellent aerial predator!
(Photo: Abi Saeed)

  • Pollinators: Insects that provide the vital service of pollination, by moving pollen from the male to the female part of flowering plants. 1/3 of all the food we eat depends on pollinators (including almonds, berries, apples, squash, and even chocolate!).
Bees, like this Honey Bee (Family: Apidae) are the most efficient
pollinators on the planet, in-part because of their anatomy:
They are covered with tiny branched hairs throughout their body
making them extremely efficient at transporting pollen!
(Photo: Abi Saeed)

  • Scavengers / Decomposers: Insects that feed on dead animals, decaying living matter and waste, assisting in the breakdown of organic matter, and returning nutrients to the soil. Without them: waste would pile up, nutrients would not recycle, and life as we know it would cease to exist!
Carrion Beetles  (Family: Silphidae) such as this one
feed on decaying animals (as their name suggests).
(Photo: Abi Saeed)

Without these vital services, the planet would be a completely different place than what we see today!

Pests actually only make up 1% of insects, so it is always a good idea to identify the critter you are looking at, before you decide to get rid of it! Insect identification services are often available through your local Extension Office, or through Ask an Expert: where you can upload photos and ask questions about insects, plants, soils, and more! 

For more information:

Thursday, May 2, 2019

Mulching in the month of May

Posted by John Stolzle, Jefferson County Extension

April Showers Bring May Flowers or, as some may call them, weeds.

Flowers such as Dandelion (Taraxacum officinale), Clover (Trifolium repens), and Henbit (Lamium amplexicaule), are important sources of energy for pollinators; Dandelions are especially important early in the spring. But their presence is not always wanted and managing these stubborn plants can be fraught with difficulty and challenging decisions. 

Mulch can be an excellent tool for managing weeds and can improve a garden’s overall productivity. A proper mulch can help to conserve and stabilize soil moisture, moderate soil temperature, control erosion, and in some cases promote soil microorganism (to the benefit of plants!).

A single mulch type does not fit all scenarios. Vegetable gardens, perennial flower beds, and trees can benefit from mulch, but specific types can be better for specific scenarios. This blog post offers a few tips and tricks for 3 common types of mulch: wood chips, black plastic, and grass clippings. In-depth information for mulching can be found in the links at the bottom of this post.

Perennial Flower Beds:
In a perennial flower or shrub bed, wood chips can help maintain soil moisture and reduce the need for watering. With wood chips, as with most mulch types, depth matters! Wood chips should be left on top of a soil. Wood which has been worked into a soil will eventually break down, but the process of decomposition can reduce a soil’s oxygen levels and tie-up soil nitrogen (to the potential detriment of plants)! While mulch can help to conserve water, watering regimens should be adjusted after laying down mulch, as prolonged periods of overly wet soil can lead to root rots! For wood chips of smaller sizes, 1-2 inches of depth should suffice for general weed control and water conservation; for larger chips of wood, 3-4 inches should do. 

Wood chips can make annual cultivation quite difficult (and can result in wood being mixed in with soil) and so generally, wood chips are not recommended for vegetable gardens or annual beds.

Vegetable Gardens:
Black Plastic

The use of black plastic, weed barriers, and fabric mulch is a challenging topic. Generally, these are NOT recommended for perennial beds, trees, or any areas with plants to be mulched longer than a single growing season. In a vegetable garden, during only a single season and mainly for warm-season crops, this type of mulch can really shine. Black plastic mulch can work very well with drip irrigation systems (beneath the mulch) in vegetable gardens, though care to not overwater should be taken. Black plastic can warm a soil, allow for earlier planting, and result in more rigorous early growth for certain plants (it is particularly great for tomatoes and other plants in the Solanaceae family). 

In the early season, a few extra degrees can really help plants get started; in mid-summer however, depending on a garden’s location, this warming factor can harm plants by overheating the soil. Some types of black plastic can also degrade in full sun. If plants are started early enough, they may grow large enough to shade the plastic and prevent this overheating; in other cases, other types of mulch can be placed on top of black plastic, though piling on too much additional mulch can reduce soil oxygen, so take care to not over do it! 

It is very important to the long-term health of a soil that black plastic or fabric mulch be picked back up after a growing season. Black plastic is not recommended as a permanent or even year-round mulch. Black plastic and weed barrier fabrics, even those with “pores for oxygen exchange”, can become clogged after a season of use, especially in clay soils. This leads to an environment where water and air are unable to penetrate a fabric. The problems just seem to mount when these types of mulch are used for more than a single season, without being picking up and removed between growing seasons. As an aside, these types of mulch can also girdle (“strangle”) trees as they grow, prevent air exchange (something tree roots need), and hamper a tree’s water supply.

All this is not to say these types of mulch are horrible choices. They can be extremely effective at controlling weeds and conserving water in vegetable gardens. Gardeners should just be aware that this mulch has fairly unique use requirements.

Grass Clippings
Grass clippings can be a great mulch for vegetable gardens. They can be mixed into a soil at the end of a season and will add nutrients to a soil as they breakdown. Grass clippings should be dried before application or they can become matted which can lead to a whole host of other problems. Recommendations for depth are around 1-2 inches. Multiple applications of grass clippings may be needed as the grass decomposes throughout a season.

One major consideration for grass clipping, especially for clippings obtained from third-parties, is whether herbicides might be present in the clippings. Herbicides are often applied to lawns, and the residual presence of an herbicide can greatly affect plants grown under herbicide-laced grass clippings.

A more thorough discussion on plastic mulch, wood chips, and a few other mulch types can be found in this factsheet on ‘Mulches for the Vegetable Garden’:

Additional Resources:
CSU Extension has put together a wonderful overview for many different mulch types (including newspaper, crushed corncobs, straw, and pine needles) which can be found here:

More general information on mulch, specifically wood and rock mulch, can be found here:

For Trees:
Wood mulch can work well, but care should be taken to avoid mulch volcanoes and mulch should be placed 6 inches away from the trunks of trees! Here is a great blog post on this very topic:

For further reading on Mulching Trees, here is a link to a document on this exact topic:

Lastly, in case it may be of interest, here is a great blog post on garden irrigation systems:

May your May be filled with gardening success!