Colorado’s 2024 Pollinator Study: A Unique Resource

By Terry Deem-Reilly, CSU Extension – Denver Master Gardener since 2003

In January, Governor Polis, in collaboration with the Colorado Department of Natural Resources (DNR), the Colorado State University Extension, the Xerces Society for Invertebrate Conservation, and the University of Colorado Museum of Natural History, released the Colorado Native Pollinating Insects Health Study. This report was commissioned by the state legislature through the passage of SB99-22 and is the most detailed scientific study ever made of Colorado pollinators.

Contents

This document is not only big historically and scientifically but also literally big, running to 273 pages that include an impressive list of citations and appendices that are worth exploring on their own. Most of the information cited comes from “peer-reviewed professional publications,” supplemented by academic and governmental research and publicly available data from databases, government agencies, and biodiversity data aggregators.

The length of the report renders a complete condensation into a blog post impossible, but I’ll attempt to outline the major sections and review the main features of interest for our CMG Blog fans.

The report is divided into an executive summary, four subject sections, the appendices, and the citation list. I’ll name and briefly summarize each of these below to (I hope!) direct readers to the pages of greatest interest.

• The Executive Summary explains the rationale and structure of and intended audience for the report. There are summaries of Sections 1 through 4 that nicely describe the contents of these sections and furnish an extremely helpful quick reference. You’ll find this section readable and informative.
• Section 1, Introduction, describes the background, participants, stakeholders and intended audiences, and organization of the report.
•  Section 2, Scientific Review of Colorado Native Pollinating Insects, discusses the importance and decline of and research on Colorado pollinators and conservation practices for pollinators and their habitats.
• Section 3, Conservation Practices for Pollinating Insects and Their Habitat, presents considerations and practices for conservation and management and federal and state agency programs, policies, and recommendations.
• Section 4, Future Priorities for Pollinating Insect Health & Management, lists five priorities for insect health and management, actions and resources to address those priorities, and a brief discussion of conclusions based on the data presented in Sections 2 through 4.
• Appendix I, Glossary of Terms, includes precise definitions of the vocabulary in the report, and a list of acronyms. (Some terms may be quite new to many readers.)
• Appendix II, Potential Pollinator Partners & Collaborators, lists names of and links to agencies and organizations that offer guidance on pollinators and pollinator conservation.
• Appendix III, Distributions of Colorado Bumble Bees, shows the distribution and range of all 24 bumble bees native to Colorado.
• Appendix IV, Imperiled Pollinator Profiles, contains “profiles of ESA-listed, candidate, and proposed threatened pollinator species found in Colorado, as well as declining pollinators that have the potential to be listed in the future based on NatureServe rankings and expert opinion.” (“ESA” refers to the federal Endangered Species Act.)  A photograph of each species is included.
• Appendix V, Information Available Upon Request, shows how to contact CSU Extension or the Xerces Society for a copy of the survey administered to state and federal agency staffs.
• Literature Cited lists the articles from scientific journals and the research compiled by academic institutions that were used in writing the report. Warning: some links have gone rotten or connect the readers to databases like ProQuest that limit access to subscribers only. To access these articles, contact your local library to see if they are available in its catalog or databases or through interlibrary loan (ILL).

Some Caveats

This report was compiled to assist state government agencies and land managers in understanding and combatting pollinator collapse; it was not intended as a guide for hobby gardeners or other members of the private sector. However, there’s a wealth of scientific data and expert observation in this study, and careful reading of the data and recommendations will give readers a leg up in making their own plans for supporting our endangered pollinators.

Some links in the list of citations have gone rotten or connect the reader to databases like ProQuest that limit access to subscribers only. To access these articles, contact your local library to check their availability in its catalog, databases, or through interlibrary loan (ILL).

And a little extra…

For help in creating your own pollinator heath program, visit the DNR’s ‘Native Pollinating Insects Health Study’ page and use the links for expert information on identifying and protecting these indispensable members of our ecosystem.

Beeing a Beekeeper

By Tracy Dunning CSU Extension – Denver County Apprentice Master Gardener, 2023

Author and backyard hive. Photo: Eric Sondermann

During Pollinator Week, you may be curious about being a beekeeper. As an urban beekeeper, let me share information about considerations in starting a hive, costs in time and money, equipment, and lessons learned in my beekeeping years.

Many people think that honey bees are endangered, but actually they are thriving in many ways. It is the other 945 species of native bees that we also rely on for pollination that are threatened, and sometimes it’s because of the competition with the honey bees.

One can only imagine how much work and how many flowers are visited as it takes 12 honey bees their entire life to make 1 teaspoon of honey according to Lisa Mason, CSU Extension County Specialist.

Considerations in Starting a Hive

It is important to think about your goals and expectations before jumping into the fascinating world of beekeeping. Do you want the honey, the beeswax, to save the bees (which don’t need saving), to learn a new and fascinating skill?

Things to consider:

• How will you learn beekeeping – a mentor, classes, or associations such as the Colorado State Beekeepers Association?
• Time commitment for inspections, mite checks, harvesting honey.
• Check the local ordinances for your community or HOA.
• Follow guidelines for hive placement in your community and for the bee’s well-being.
• Cost: usually $500-$1000 to start, but my experience was very different (see below).
• Selling honey requires following special rules for cottage industries.
• Weather changes and extremes in Colorado make for challenges.
• Be sure to tell your neighbors and give them periodic jars of honey for good relations.

Equipment

Hive box: There are three main types of hive boxes: the more common Langstroth, the Top Bar, and the Flow Hive. See this video from Adams County Extension for details.

Tools: Brush, hive tool, smoker. Photo: Tracy Dunning

Tools: The basic tools are a brush, a hive tool for prying the frames out, and a smoker for calming the bees when doing an inspection.

Protective clothing: Depending on your comfort level, you may need gloves, a hood to protect your face, a bee shirt or a full suit. You may notice in the video link below that the beekeeper is barehanded; some beekeepers do not use protective clothing as most bees will not sting unless in self-defense.

Getting the Bees

There are several ways to get your initial bees:

• Buy them as a package of bees or a nuc. Cost is usually $100-$350. Here is a video of Adams County Extension putting the queen and bees from a bee package into a hive.
• Beekeepers will often split their hive to prevent a swarm.
• Catch a swarm which is how I started and it’s free. (My hive box was also a free hand-me-down.)
• Find more on costs of beekeeping here.

Author setup to catch a swarm above the box on the fence. Photo: Ted Ramsey

Lessons Learned

• Some beekeepers intensely practice their craft with monthly inspections, special feeding, marking the queen, etc. Even with managed care there is a 30-60% hive loss. My approach with my mentor has been more hands off, believing that the bees have been managing on their own for hundreds of years.
• It is, however, important to treat for mites on a yearly basis. This Integrative Hive Management Guide provides detail.
• Having a variety of flowering plants all season long is important as the bees need a supply of nectar and pollen. Native plants are the best, and double flowers with lots of petals are less visited. Find excellent information on feeding bees here.

Honey bee on Biokovo Cranesbill – notice pollen on abdomen and on legs under wing. Photo: Tracy Dunning

• One time I was appalled to find a pile of dead bees outside the hive. I didn’t realize that in winter, the drones are all kicked out of the hive so they don’t eat the honey.
• My hive swarmed a couple of times when we didn’t split in time. This is when there are many bees so a new queen is created and the old queen leaves with half the bees. This means that there may not be much honey to harvest that year as bees need 80 pounds of honey to overwinter.
• Be sure that you have a shallow water source nearby; my neighbors didn’t appreciate all the bees drinking from their pool.
• Many hives were lost in the deep freeze last winter, but putting insulated boards and pads around the hive protected my bees. They are amazing as they stay warm by huddling in the center of the hive, flapping wings to generate heat, and rotating from the outside to the inside of the huddle.
• Although some beekeepers don’t mind getting stung, one friend eventually developed an anaphylactic reaction and had to give up beekeeping altogether. I prefer to stay protected when opening the hive.

Backyard beehive with variety of flowers for nectar and pollen. Photo: Tracy Dunning

Watching bees closely and learning to be a beekeeper is a wonderful experience. Is it right for you? This is a great resource to help you decide.

Celebrating Pollinator Week with Kids

By: Molly Gaines, CSU Extension-Denver Master Gardener since 2019

A Tiger Swallowtail hovers above a zinnia. They collect pollen by brushing their wings across flowers. Photo: Molly Gaines

Summer in Colorado is heading into full bloom, with bees, butterflies, moths, birds, and other pollinators abounding in our backyards and across the Rocky Mountains. At the same time, Pollinator Week, created by Pollinator Partnership to promote the health of pollinators through conservation, education and research, kicks off June 19. This makes it a perfect time to celebrate pollinators with the kids in your life, observing pollinators in action and creatively acknowledging the special roles they play in our environment. 

There are many engaging ways to help kids of all ages learn about pollinators. Some basic facts you can share about pollinators include:

• Pollinator species include bees, beetles, flies, moths, butterflies, hummingbirds, and bats.
• More than 70% of the world’s flowering plants rely on pollination, which is essential for producing fruits and seeds.
• Just like humans and other animals, pollinators need food, water, shelter and space.
• Pollinators are in trouble, and there are some reasons why and ways we all can help.

For a wealth of background and education about pollinators, check out the Pollinator Partnership’s website. It offers planting guides, bee guides, guides to creating a pollinator garden, pesticide education, and much more. 

The following are a few fun ideas to teach the kids in your life more about pollinators, along with a few resources for reference. 

1) Take a walk around your neighborhood. One of my favorite things to do with my own kids is to stroll through our neighborhood observing pollinators in action — a butterfly hovering around milkweed or a bumblebee deep inside a squash flower. It’s delightful to slow down and watch all of the ways pollinators move and work their way through our natural environments. And, if you look closely at a honeybees’ legs, you can see and point out to kids the yellow pollen they’ve collected and are carrying back to their hives. For a list of plants that are native to Colorado that might be found along your stroll, check out this blog post by Denver Master Gardener Kathy Roth.

A honeybee helps this cucumber grow fruit. Photo: Molly Gaines

2) Plant pollinator-friendly plants or a tiny garden to attract them. It’s not too late to find pollinator-friendly flowers at your local nursery and plant them with your kids. Or, you could plan now to plant a fall pollinator garden. Some great ideas for what to plant and background on how pollination happens can be found here. When your garden is complete, have your kids visit www.pollinator.org to download free garden signs. Older kids can help make signs to place in their garden, and perhaps a neighbor’s pollinator-friendly garden, too! 

3) To find an abundance of pollinators in one place, consider a visit to the Denver Botanic Gardens, Chatfield Farms or the Butterfly Pavilion in Westminster, Colorado. The Butterfly Pavilion is hosting a Pollinator Palooza Festival on Sun., June 25, to celebrate all things pollinators.

Did you know grasshoppers are unconventional pollinators? Photo: Molly Gaines

4) Throw a pollinator party with your kids, a few of their friends, and neighbors or family. Serve yogurt parfaits with berries, granola and a drizzle of honey or sugar cookies cut into butterfly or bee shapes. Give away a favor of 2-3 honey sticks and tie with garden twine. Make seed bombs with pollinator-friendly garden seeds. I’ve done this before with kids and there are several ways to do it and kids love making them! Consider downloading free pollinator art (there are many options online) and have kids color with crayons or markers. Invite a neighborhood beekeeper to show off a frame from his or her hive and some beekeeping equipment. Have kids do pollinator chalk art on the sidewalk in front of your home.

These are just a few ideas to help kids connect the dots between pollinators and their environment. Teaching young people about the essential role pollinators play in nature and our food supply is a great step towards helping future generations care for them. And care is what will help ensure pollinator populations thrive once again.

Native and Diverse, Our Solitary Bees

By Lori Williams, CSU Extension – Denver Master Gardener since 2016

There are approximately 4,000 species of bees found in North America: 90% are native to the USA, Mexico, and Canada, and the remaining 10% are European honeybees transported here by pilgrims and other world travelers. In Colorado there are over 900 native bee species.

A native green metallic sweat bee (Agapostemon spp.) foraging on an evening primrose flower (Oenothera sp.). Photo: Lisa Mason

CSU’s Fort Collins campus is a Bee Certified Campus so it’s bee-friendly and also bee-autiful! CSU also offers an exceptional community science project, Native Bee Watch that encourages Coloradoans to engage in research and education to support pollinator conservation. The website is a trove of information and ideas for encouraging and learning about native bees.

Research Says:  Solitary Native Bees Are Giants of Pollination!

Due to their ‘technique’ when visiting plants, native bees basically pollinate everything along their daily route be it an alfalfa crop, an orchard, our backyard flowers, or the neighbor’s veggie plot. 

Here’s more about these ‘super-spreaders’:

• Solitaries have a habit of ‘belly flopping’ into the plants they visit. Pollen then sticks all over them. As they move on, they generously deposit this pollen on plants in their path. 
• Natives supplement the organized and human-assisted honeybees, which are often transported thousands of miles to aid farmers in crop pollination. Native bees very effectively pollinate plants within the travel radius of their nest.
• Graceful, maybe even messy in their daily routines, solitary bee activity contributes significantly to food production, blooming blossoms, and microclimate success. 

Native Solitary Bees Compared to European Honeybees

Solitary bees look, behave, and live somewhat differently than non-native honeybees. Here are some notable comparisons:

• Solitary bees are typically smaller (1/4” to 3/4” in length) than their European compadres. They can be black, dark blue, or metallic green.
• Natives live solo in nests they create using natural materials (mason bees use mud, leaf cutters line their nest with leaves and beyond). Many species nest underground. Non-native honeybees are communal dwellers and live in hives often provided by humans.
• No job goes undone for solitary bees – they do every job needed to live and reproduce.
• Every native female is a queen. She collects pollen to store in her nest for each egg she produces in an approximately 6″ long nest, housing 6-10 eggs. Every male is born to mate as he emerges and then dies so on this point, honeybee males/drones are pretty similar.
• Honeybees work as a community to collect pollen and make generous amounts of honey for the queen, her eggs, and harvesting. Native bees don’t create honey, nourish themselves as they go, and leave the exact amount of pollen for their eggs to eat before they emerge from the nest. 
• Honeybees have aggressive guard bees at hive entrances. Native bees don’t have time for this as they are busy eating, nest building, and collecting pollen for their eggs. They typically say ‘oh hello, excuse me, I’m off’ to anyone looking around their haciendas. Most don’t even have barbed stingers.
• Diverse native bee populations are not susceptible to mono-species diseases, pests, or Colony Collapse Disorder.

Creating Solitary Bee Habitats 

It’s easy and beautiful as they love flowering ‘stuff’ and need four basic ‘things’ to create nests, lay and protect eggs, and store pollen and nectar: food, water, shelter, and a solitary space for their nest. You’ll find this CSU Fact Sheet and video provide lots of details on creating habitats.

Here are some key tips:

• Design gardens with plants that bloom in waves to provide food and nesting materials spring through fall. A mix of bloom sizes, colors, shapes, and timing will keep them happy. 
• Native bees are four times more attracted to native plants than non-natives.
• ‘Bird’ baths are for all pollinators: bees, butterflies, birds, and more. Creating a ‘beach’ or place to land in your water source offers pollinators a resting place while they hydrate.
• Insecticides and pesticides with any bee, bird, beneficial bug, or other pollinator are not a good mix.  Please evaluate carefully when considering the necessity of using these products and always follow directions to a T, for your safety too.
• Stacked ‘log hives’ offer great habitat, so do cracks in tree bark and undisturbed ground, leaf mulch also creates nesting opportunities. Wooden homemade bee ‘hotels’ that are south facing are welcome refuge for happy homemaking solitary bees, too.

Bees out after a spring snow!

Be sure to keep your eyes peeled for these fascinating bees and consider their needs when working in the garden!

Pollinator-Friendly Fall Garden Cleanup

By Jessica Harvey, CSU Extension – Denver Master Gardener since 2020

As we wrap up the season and put our gardens to bed, there are a number of ways we can help provide habitat for our pollinators in the process. Many pollinators will nest in the hollow of stems or wood. Others will use things like leaves, mud, plant hairs, and resin to build their nests for the winter. Rather than chopping everything down and clearing out the remaining debris, let’s consider whether any of it may be used by a pollinator this winter, or even next spring.

For those pollinators that like to nest within hollow stems, consider deadheading rather than chopping those stems down to their base. Stems can range 8 to 24 inches long, from both flowers and grasses alike, to be of use for cavity nesters. A nest within a hollow stem will typically house eggs, a food source and a natural plug of some kind that can be specific to the type of pollinator that are nesting within. A couple of great examples are leaf cutter bees (Megachile) and Mason bees (Osmia and/or Hoplitis). 

Remember to allow those same stems to decay and fall on their own in the spring as you don’t want to remove them until after the young have emerged for the season. If you grow raspberries doing so is easy, since you may need those prime canes for next year’s production.

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  Raspberry canes in the Spring. Photo: Jessica Harvey
  

Check out this great handout with diagrams highlighting some of the different cavity nesters from University of Minnesota Extension and their Bee Lab. 

Not to be forgotten, consider pollinators that are ground nesters as well. It’s important to leave some bare earth for these guys to burrow into for their nests. If you have pets or children, you may consider a place out of the way within your garden.

Another excellent resource is CSU Fact Sheet No 5.615 Attracting Native Bees to your Landscape which provides more information on different nesting materials and ways you can provide additional habitat specifically for native bees. 

Just like any other living thing, the main concerns for pollinators are food, water, and shelter. As we clean up and leave some debris intact for them as shelter, it’s also important to try to provide some clean water. It may be hard to do this during the winter but consider adding a tray with pebbles near your hollow stems or bare ground, and keep it topped off during the fall and spring. No need to buy anything specifically marketed as such, it can be as simple as the drip tray from a container you aren’t using.

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  Drip tray in community garden. Photo: Jessica Harvey

As we wrap up for the season and begin planning for the next, also consider whether you have a year-round source of both pollen and/or nectar within your garden to encourage a strong pollinator population. Ground covers, winter blooming crocus and early blooming grape hyacinths (Muscari) will help to bridge some of the gaps.

CSU Factsheet 5.616 Creating Pollinator Habitat gives a glimpse of all the things to consider as you plan your garden as a pollinator habitat, including some plants to consider for all season provisions.

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It’s important to remember our pollinators not just during the peak of the season when we need them for our flower, fruit, or vegetable production. They provide so much for us and we need to try and return the favor wherever we can. 

Denver Master Gardeners Look Back at the Growing Season – Part 1

Compiled by Linda McDonnell, Denver Master Gardener since 2013

It’s time to take stock of the gardening year – the ups, downs, and lessons learned. In this two-part series, eleven Denver Master Gardeners share the highs, hiccups, and take-aways from the season. Let’s see what they’ve been up to!

A NEW ROCK GARDEN Steve Aegerter, Denver Master Gardener since 1999

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  Photo by Steve Aegerter

If you attended the Rocky Mountain Chapter of the American Rock Garden Society’s 2021 Spring tour, you had the opportunity to visit Steve’s new rock garden, which was planted only a month before the June event. Steve explained that “Plants were either grown from seed or obtained through Denver Botanic Gardens, Colorado Native Plant Society, or the local American Rock Garden Society.”

The garden contains fourteen low-water plants including  ‘Butterfly Yellow’ mullein (Verbascum roripifolia), Freemont’s evening primrose (Oenothera macrocarpa freemontii), and a unique pale yellow upright bellflower, Campanula thyrsoides.

Steve is pleased with the garden’s progress and looks forward to it thriving on little to no supplemental water soon.

PILL BUG INVASION Felicia Brower, Denver Master Gardener since 2020

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  Photo by Felicia Brower

Heartbreak is waking up early to check on your plants, only to find them withered and discover that their stems have been destroyed. The majority of my cucumbers, squash, and beans were decimated no matter how many times I tried to replant them. I had three varieties of cucumbers, six varieties of squash, and five varieties of beans. All but two varieties of beans were killed. Out of the two beans that survived, half of the black-eyed peas were eaten but my Zuni Gold beans, a regional bean cultivated in the Southwest over many generations, were left untouched.

Moisture and too much organic matter in my raised beds lead to this explosive pill bug population. I’m working on amending that now, and next year I’ll take pest control seriously early on.

PICTURE PERFECT ‘RED ACRE’ CABBAGE Latasha Dunston, Denver Master Gardener since 2020

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  Photo by Latasha Dunston

Seed grown ‘Red Acre’ cabbage (Brassica oleracea) was a highlight of Latasha’s West Washington Park community garden. An earlier attempt to grow this plant didn’t work, but this year, the results were stellar. “I kept the base leaves and root in place when I harvested, and the plant produced four new heads!” She’s hoping for more in a fall harvest, too.

ADD THIS ONION TO YOUR “MUST GROW” LIST Jill Fielder, Denver Master Gardener since 2013

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  Pixabay.com

This season, Jill’s best new find was bunching onions also known as spring or Welch onions (Allium fistulosum).

Jill reports that these flavorful gems can be planted when the weather is still chilly and harvested at any point during the growing season. Early on, use like tender scallions. Later, use the greens for stir fries and the bulbs as you would any small onion. Seed in a full row so you have plenty to harvest as the season progresses. Eat the entire tasty plant. There’s even a French Purple variety that offers rich beautiful color for snipping into salads or sprinkling over bubbly enchiladas. Didn’t plant enough the first part of the season, so planted more mid-summer. All were delish!

DAHLIA ADVENTURE & DREADED TWO-SPOTTED SPIDER MITES Cindy Hanna, Denver Master Gardener since 2010

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  Photo by Cindy Hanna

Last fall I was given a treasure trove of dahlia bulbs that had been dug out of a bed in Park Hill. I was told to, ‘clean them off, split as needed leaving a bud on each piece, make sure they are dry, and store in a bin of perlite in a dark room until Spring. In Spring when they begin to sprout, plant according to varied directions online.’ High maintenance. They were slow to sprout and bloom but, wow, worth the work and wait!

When it comes to pests, I’m a bit of a live-and-let-live gardener. So, when my Master Gardener friend who is an avid plant and bug expert visited, I feared the worst. She identified two-spotted spider mites in my vegetable beds. If there had only been two, I could have ignored them. But there were thousands living on the underside of the yellowed foliage, sapping the energy and beauty from my cucumbers and beans.

RAVE REVIEWS FOR “GARDEN IN A BOX” Lynn Ireland, Denver Master Gardener since 2020

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  Photo by Lynn Ireland

Rather than starting from scratch, Lynn decided to add pollinator-friendly plants to her established gardens. A highlight of her project was “Garden in a Box”, a collection of low-water plants, purchased through Resource Central in Boulder, which also comes with planting directions and design tips.

Several water districts offer “Garden in a Box” programs, some with rebate offers. Lynn suggests “It’s the perfect way for a novice gardener to begin or add to their gardens.”

Stand-out plants in the garden expansion included Agastache, Aster, Sea Kale, Mexican Sunflower, and Pitcher Salvia. “According to the hummingbirds, native bees, and Japanese Beetles, these two gardens have been bountiful all summer. I’m already excited for next season!”

Watch for more garden recaps next week…

How to Lure Butterflies to the Garden

By Linda McDonnell, CSU Extension Master Gardener since 2013

A quick note of thanks for supporting last month’s Denver Master Gardener on-line plant sale. We hope the plants are healthy and productive additions to your garden and that next year, you’ll join us for an expanded in-person sale. Now, let’s talk butterflies…

Butterflies are prized for their striking appearance and graceful flight paths. A butterfly sighting in my garden is always a stop-and-appreciate-nature moment. Perhaps more importantly, butterflies are valuable pollinators and an important element in the food chain.

Painted Lady on Echinacea (Pixabay.com)

Here are five features of butterfly-friendly habitats.

Host Plants

Most butterflies require specific host plants for caterpillar development. Perhaps the most well-known butterfly/host plant partnership is the monarch and milkweed plant, Asclepias spp. (It’s worth noting that Colorado is on the edge of the monarch migratory corridor, so we see them rather infrequently.)

Two common butterflies in our state are the black swallowtail, whose caterpillar develops on parsley, dill, and related plants and the painted lady which seeks thistles, hollyhocks, and sunflowers.  Colorado State University has a list of our state’s butterflies and their caterpillar host plants here.

Food Sources

Mature butterflies seek sugary nectar for energy and nutrition and pollinate plants by moving nectar from one plant to another. An ideal environment has a season-long sequence of nectar producing blooms. Examples include spring blooming lilacs (Syringa vulgaris); mid-summer asters (Aster spp.) and Bee Balm (Monarda); native shrubs such as Rabbitbrush (Chrysothamnus nauseosus); annuals including Marigolds (Tagetes spp.) and Cosmos (Cosmos spp.); and weeds like dandelions and some thistles. Even the honeydew secretion from aphids provides sugary sustenance for butterflies.

Avoid double-petaled flowers which make it difficult for the insects to reach the nectar source. This article offers many suggestions for plant selection.

Black Swallowtail on Lantana (Pixabay.com)

Water Source or Mud-Puddle

A shallow dish with water or a mixture of garden soil and water will attract butterflies. A rock or other flat landing pad in the dish encourages drinking. It is reported that males are especially attracted to the nutrients in a mud-water cocktail. 

Sunny Open Areas and Wind Protection

Swaths of sunny plants are ideal for foraging while densely planted trees and shrubs provide shelter from harsh winds.  An ideal butterfly habitat provides both.

Insecticide-free Plants

Insecticides can be lethal to butterflies in all stages of development. Eliminating or reducing the use of insecticides will increase the populations of both the butterflies and other beneficial insects such as lady beetles and green lacewigs.

Resources and References

Colorado State University Fact Sheet 5.504 “Attracting Butterflies to the Garden”

The Denver area has two great sources for butterfly education: The Butterfly Pavilion and the Butterfly House at the Chatfield Farms location of the Denver Botanic Gardens. Both make for fun, educational outings.

Wild About Natives: Native Plants for Colorado Pollinators

by Kathy Roth, CSU Extension-Denver Master Gardener since 2018

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  Leafcutter bee (Megachile spp.) on a native sunflower. Photo credit: Lisa Mason of Arapahoe County Extension

May is a wonderful month to celebrate spring and is typically when Colorado gardeners experience the last frost of the season (~ May 9th in the Denver area, later at higher elevations).

Plants set in the ground this month will likely be well-established and possibly even blooming by Pollinator Week (June 21-27).  Pollinators include butterflies, moths, hummingbirds, bats, beetles, flies, and bees.

In this post we will look at several features of pollinator-friendly landscapes and provide numerous resources for further learning.

Creating a Pollinator Habitat

A pollinator habitat is a welcoming environment which provides food, water, shelter, and space. It includes a variety of plant species, offering nutrition and a nesting opportunity from early Spring to late Fall. Clusters or swaths of the same plant encourages efficient foraging. (CSU Fact Sheet 5-616)

Flower shape, fragrance, color, and pollen are among the plant traits which attract pollinators. To learn more about the preferences of several pollinators, visit pages 10-11 of this publication from The Pollinator Society.

Attracting Native Bees

Did you know there are over 20,000 bee species throughout the world with 946 of these being native to Colorado?  And that unlike honeybees, most native bees are solitary and inhabit underground nests or dried plant stalks?

This CSU fact sheet explains that “studies have shown that native plants are four times more attractive to native bees than introduced ornamentals.”  It goes on to say that “native bees vary greatly in size, shape, and color” and that “most of the native species in Colorado are simply not inclined to sting or do not have enough venom for a painful sting, even if they try.”

The Colorado Native Plant Society (CNPS) discourages the use of chemical pesticides, which can harm pollinators. However, if pesticides are necessary, apply near dawn or at dusk, when pollinators are less active. Never apply pesticides when pollinators are present and follow all label instructions.

Interested in learning more about native bees? Lisa Mason, Arapahoe County Horticulture Agent, invites the public to assist in a “Community Bee Watch”; for more information and to participate in this citizen science project, contact Lisa at nativebeewatch@gmail.com.

Perennials and Shrubs for the Pollinator Garden

Native perennials are ideally suited to Colorado’s growing conditions and require less water, fertilization, and soil amendments than non-natives. You may already be familiar with some native perennials such as Blanket flower – Gallardia aristate, Blue Flax – Linium lewisii or Yarrow – Achillea millefolium, but these are just a few of many.

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  Blanket flower. Photo credit: Pixabay

This CSU publication has an extensive list of perennials to choose from with details on bloom time, color, moisture requirements, pollinator attraction, and more.

CNPS offers landscape tips and plant recommendations in this brochure.

Native shrubs offer an outstanding opportunity for pollinator sustenance and shelter. Three highly recommended shrubs for the pollinator-friendly landscape include:

Left to right: Woods Rose, Rabbitbrush, Boulder raspberry. Photo credit: USDA

Rabbitbrush – Chrysothamnus nauseosus (Bright yellow flowers late summer; up to 6’ tall if not pruned in early Spring.) 

Boulder Raspberry – Rubus deliciosus (Large white summer flowers evolve into berries for wildlife.)

Woods Rose – Rosa woodsii (Pink flowers in summer; red/brown prickly stems; red-orange hips in Fall. Caution: suckers readily!)

See last month’s Wild About Natives post for additional shrub recommendations.

Tips for Designing a Pollinator Garden

Creating an attractive, environmentally sensitive garden can sometimes feel overwhelming. Here are two landscape plans with plant lists to inspire your creativity.

The Denver Botanic has several gardens dedicated to native plants. Visit in-person (check COVID admissions requirements) or online.

Email questions about specific plants, with relevant photos, to gardeninghelp@botanicgardens.org. Denver Master Gardeners will provide a science-based response. CNPS is another valuable resource for native plant education.

Thanks so much for your interest in native plants, watch for the next Wild About Natives post in June.  

Gardening With Seasonal Allergies

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There are an estimated thirty five million people in the United States who suffer with seasonal allergies. If you’re not affected, you likely know someone who is. For gardeners, pollen and molds are the most common allergens.

Wind-Pollinated versus Animal-Pollinated Plants

Pollen is a powdery substance from the male part of a flower (stamen) or cone which can fertilize the female ovule. Pollen travels by animals, insects, or wind.

Wind-pollinated (anemophilous) trees, shrubs, perennials, and weeds produce  airborne, toxic pollen. Common characteristics of these plants include small, inconspicuous, often petal-less flowers, which generally lack bright colors and have little scent or nectar.  Examples include Cottonwood trees, Gambel oak, Rocky Mountain Maple, Ragweed, Dandelion, and turf grasses. A comprehensive seasonal list of Denver’s highly allergic plants can be found here.

According to the U.S. Forest Service, wind pollinated plants “release billions of pollen grains into the air so that a lucky few will hit their targets.”

By contrast, animal or insect-pollinated plants are not usually responsible for pollen allergies. If a bee or butterfly feasts on the plant’s pollen, it is less likely to be the cause your watery, itchy eyes. Flashier and generally more colorful, these plants produce pollen which is stickier and contain large, heavier particles. The “stickiness” is what helps the animal transport pollen from one plant to another.

Mold Allergens

Molds are found in partially decomposed compost piles, dried leaves, branches and bark mulches, are present nearly year round in Colorado and can be very toxic.  Spring clean up is prime mold allergy season.

Climate Change and Allergy Season

William Anderegg, a researcher from the University of Utah found “…a strong link between warmer weather and pollen seasons provides a crystal-clear example of how climate change is affecting people’s health across the United States.” Further, his study concluded that as compared to 1990, the current pollen season starts twenty days earlier, lasts ten days longer and contains twenty one percent more pollen.

Tips for Gardening with Allergies

Here are a few things to consider to manage allergies while gardening:

• Mow lawns short so turf does not set seed or have someone else do the mowing. 

• Replace turf with groundcovers or suitable plants.

• Substitute rock mulch for bark mulch, which can harbor mold.

• Reduce exposure to a compost bin – mold can be present in unfinished compost.

• Pay attention to local pollen counts.

• Repurpose your mask. It will keep pollen from your nose and mouth.

• Cover up – hats, long sleeves, glasses also help.

• Change clothes when you come inside and shower promptly.

Additional Reading

National Jewish Hospital, Pollen Count for Denver, Colorado

As Climate Change Extends Allergy Season, Pollen Travels

PlantTalk Colorado #1758, Cottonwood Trees

Harvard University. Allergies? Tips to Minimize Your Mold Exposure

Written by Linda McDonnell, Denver County Master Gardener since 2013

More Thanks for Our Gardens

Giving Garden Thanks – 2020
By Parry Burnap, CMG since 2016

My psyche unsettled in waking and sleeping hours by
flames, floods, blowdowns, protests, and infections,
across the lands, on our streets, within our families, in our lungs.
My heart aching from the sacrifices of the most vulnerable among us,
smiles covered, hugs restrained, and gatherings digitized.
2020, my 65th year,
called into question the little I thought I understood.
Tectonic forces cleared the way for an unknowable time I likely will never see.
These days were a long time coming and will be a long time still.

Safe at home with more time and attention that I could not spend elsewhere,
I walked steps to the garden, further than any vehicle could have taken me.
Pollinators loaded heavy with yellow dust buzzed clumsy in the dance of life.
Answers revealed themselves in cycles of rebirth and exquisite order
within riotous transformation.
Dumbstruck by color and light, I was surprised by Joy.
Nourishment and sanctuary, the garden was my place and time,
my guide to here and now, where I start over and over again
to do the never-ending work at hand.