Noxious weeds can reduce ecosystem function

By Irene Shonle, Gilpin County

Noxious weeds pose a growing threat to our general ecosystem.  These non-native plants  have a competitive advantage over our native plants because of the lack of insects and diseases that control them in their native countries, and they are spreading rapidly on both private and public lands.

Oxeye daisy monoculture

The reason this is such a problem is that these new invaders do not have an evolutionary history with all of the rest of the plants, insects, birds, and other wildlife that depend on our ecosystem.  The introduction and establishment of invasive plants into new habitats in which they have not coevolved with the native organisms have been identified as a major threat to biodiversity and ecosystem structure and function (Bezemer et al. Annual Review of Entomology 2013).

Plants are the bottom of the food chain, with insects and a variety of mammals eating the plants directly, and then other species such as birds and mountain lions eating the insects and mammals. Non-native plants such as noxious weeds don’t provide that bottom rung of the food chain. This is because 90% of herbivorous (plant-eating) insects are fairly host-specific and may not recognize unfamiliar exotic plants as food.  Many mammals also may hesitate at eating new plants. When weeds crowd out the familiar native plants, the entire food chain is weakened.

This hummingbird moth caterpillar is eating native fireweed

Examples of our ecosystems collapsing due to this weakening are coming at an alarming pace. A recent paper (Sánchez-Bayo et al., Biological Conservation 2019) presented a comprehensive review of 73 historical reports of insect declines from across the globe. More than 40% of insect species are declining and a third are endangered, the analysis found. The main drivers of species decline, according to the study, are (in order of importance): “i) habitat loss, ii) pollution, iii) biological factors, including pathogens and introduced species; and iv) climate change.”  The effect of noxious weeds can be seen twice here, once in habitat loss, and once in the introduced species bucket.

Additionally, noxious weeds have the potential to reduce the connectivity of native plant patches by forming large monocultures. Wide swaths of noxious weeds could isolate suitable habitat patches, thereby increasing the local extinction risk of native herbivores, pollinators, and their natural enemies, since many insects fly only short distances and smaller populations are more vulnerable to getting wiped out by natural disasters or other events.

Large Canada thistle infestation

Native pollinators are critical for pollinating native plants (which brings future generations of plants), and invasive weeds can disrupt their pollination. Several large analyses have shown that invasive plants, on average, have a negative effect on the visitation rates of pollinators and reproductive success of the native plants around them (Morales and Traveset, Ecological Letters, 2009 and Montero-Castano and Vila, Journal of Ecology, 2012).

So, these are all reasons why it is so important to keep the populations of noxious weeds to a minimum on both private and public land.  Learn how to recognize the noxious weeds that are in your area (here is a link to all the Noxious weeds in the State:   https://www.colorado.gov/pacific/agconservation/noxious-weed-species  Then, take care of them on your property, and if you see weeds on public property, notify the appropriate land manager. This is an easy way we can all contribute to the health of our ecosystems.

Colorado's Yellow Stripey Things (Stinging Insects)

Posted by: Abi Saeed, Garfield County Extension

Colorado is home to endless outdoor activities, especially in the summer months. The state is also home to an abundance of flora and fauna, including native and non-native species of some stinging insects, which can sometimes get in the way of that outdoor fun. Most of the time, a select few of these nuisance species are responsible for most stings and unpleasant encounters. However, not every yellow stripey buzzing thing is a pest, and most bees and wasps mind their own business, and go about their day collecting food and resources (seldom noticed by anyone). In fact most of these insects (including those mentioned below) are considered to be beneficial organisms that play a role in providing valuable services: bees are well-known pollinators and most wasps are important predators and parasitoids of several other arthropods, which help keep pest populations at manageable levels.

A European Paper Wasp Nest located in a Western Colorado shed:
Nests like these in high-traffic areas can lead to unpleasant interactions.
(Photo: Abi Saeed)

Here are two of the most common stinging wasps of Colorado:

1. Western Yellowjacket (Vespula pensylvanica)The Western Yellowjacket is a common, ground-nesting wasp, and can be aggressive if you are near their nest. They can be found scavenging a variety of foods, including sugary foods high in energy, dead insects / animal carcasses, and trash. They are a social wasp, meaning that they nest communally (with 100s of individuals in a strong nest) and work together to gather and protect resources. This wasp is commonly found in outdoor areas, and their nesting choices can sometimes bring them in close proximity with outdoor enthusiasts, gardeners, and picnic-goers. This insect is the most important stinging pest in the Western United States, and can be aggressive if you find yourself too close to their nest. Their nests are not readily visible, because they are underground- and Yellowjackets will abandon their nests and rebuild a new one each year.
2. European Paper Wasp (Polistes dominula)
   Similar in appearance to yellowjackets, European Paper Wasps are non-native wasps (arriving to Colorado in 2000). They create a small paper nest (made of chewed up wood fibers), and will readily utilize small spaces in which to build them (including under leaves, overhangs, and small cavities). Their nests (and colony size) will grow over the course of the summer- and larger nests can have up to 100 individuals. These are predatory social wasps, which hunt and capture other live insects to feed on. They are also an annual wasp, and will rebuild their nests every year.
   
   Aside from the above wasps, there are a few other insects that are known to sting (though, usually only when disturbed/threatened):
3. Baldfaced Hornet (Dolichovespula maculata)
   Baldfaced hornets produce a large characteristic above-ground paper-enclosed nest (usually placed in trees/shrubs and other out of the way places). Colonies of these social wasps contain 400-700 workers, and have omnivorous feeding habits. They will abandon their nest in the fall and rebuild a new nest the following year. They are a beneficial insect, playing a role as a predator of several arthropods.
4. Bumble Bees (Bombus sp.)
   Bumble bees will nest in existing cavities in the ground (such as old rodent burrows) and build a nest to start a colony. Number of bees within a nest can vary between 50-400 individuals, depending on the species. They build a new nest each year, but a new queen can find and use the same cavity to build a nest the following year. Bumble bees are vital pollinators and provide valuable ecosystem services.
5. Honey Bees (Apis mellifera)
   Honey bees, arguably the most famous stinging insect and most charismatic pollinator, are often blamed for stings that come from other insects. European honey bees are usually mild-mannered, making them a great human companion (just ask a beekeeper!). They nest in large perennial colonies, ranging from 10,000 – 50,000 (or more) individuals in a nest (usually in hives tended by humans or cavities found in nature). These bees will only sting if they perceive a threat, and can guard their hives from predators and honey-loving scavengers. Workers in a hive can only sting once, due to a barbed stinger (that will lodge itself into the victim, and remove the connected digestive system- resulting in the bee’s death). Queen bees (smooth stinger) can sting repeatedly, though they usually only use this as a weapon against other queen bees when competing for a nest. Honey bees are vital pollinators, and provide important ecosystem and agricultural services (including crop pollination across the world). 

It is important to consider the fact that: although many of these insects have the capability to sting- they provide important ecosystem services including pollination and pest control, without which our landscape would be very different from what we see today. Minimizing the proximity to their nests can play a role in reducing unpleasant interactions, and removing colonies from high-risk areas (including near playgrounds, schools, indoor structures, and patios) can sometimes be necessary.

An abandoned Baldfaced Hornet Nest, opened up to demonstrate
the inner cell structure, and external paper coverings.
These nests will be abandoned in the fall, and rebuilt in the spring.
(Photo: Abi Saeed)

To learn more about some of these nuisance wasps, and how to trap them, check out this Blog Post:
http://csuhort.blogspot.com/2019/04/springs-not-so-nice-things.html

For more information summarizing these stinging insects, check out these resources:
https://webdoc.agsci.colostate.edu/ipm/COStingingInsectsFINALgb.pdf
https://extension.colostate.edu/topic-areas/insects/nuisance-wasps-and-bees-5-525/
https://extension.colostate.edu/topic-areas/insects/european-paper-wasp-5-611/

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.

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 3^rd 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, swcoloradowildflowers.com)

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 swcoloradowildflowers.com 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.

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 4^th-8^th 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. 

They're Baaaaaaack! Voles.

Posted by Alison O'Connor, Larimer County Extension

Well...to 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.

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.



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.


               
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!!!