Colorado Gardening Calendar for April 2024

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

Last week’s snow covering forsythia starting to bloom. Photo: Molly Gaines

Signs of spring are everywhere in Denver. Daffodils, crocus and other spring flowers in full bloom one day; covered in ice and snow the next. Oh, to be a gardener at 5,280 feet!

While it’s too early to spend a lot of time planting, it’s a perfect time to prepare your soil, garden beds, tools, pots and lawn for the 2024 growing season. Below are a few gardening activities to consider before Mother’s Day, May 12 (around the safe zone from hard frosts) for planting most plants, flowers and vegetables.

Crocus are always a welcome first sign of springtime. Photo: Molly Gaines

As you plan your garden, it’s worth noting that some of the Denver metro is in a new gardening zone. Last November, the USDA announced updates to its “Plant Hardiness Zone Map,” updating this go-to tool for gardeners for the first time since 2012. The new map, which can be found here, places parts of Denver in Zone 6a rather than 5b. Zone numbers reflect the average extreme minimum temperatures and help determine what plants will thrive in each zone.  Higher numbers equal incrementally warmer low temperatures. For background about how to use this map as a planting guide, visit this helpful article from the National Gardening Association’s learning library.    

New USDA Plant Hariness Zone Map now places parts of Denver in Zone 6A. Credit: USDA

Vegetable Garden

• Clear remaining debris. Pull emerging weeds.
• When the soil is dry, add a fresh 2-3-inch layer of compost to your beds. This supports soil health and plant vigor. Gently work compost into the top layer of your existing soil with your hands, a trowel or a cultivator. Let rest a few weeks before planting.
• Plant frost-tolerant spring plantings, such as peas, spinach, arugula, radishes, Swiss chard, etc.
• Start indoor seeds for warm-weather vegetables such as tomatoes, peppers, squash, melons, etc.
• Reference this Vegetable Planting Guide to plan what you will plant when.

Trees & Shrubs

• The snowpack is solid Colorado-wide this year, well above 100 percent. This includes Denver. That said, if this month is dry, be sure to water your trees and shrubs.
• Early this month, prune deciduous trees, conifers and summer-blooming shrubs.
• Later in April into mid-May, prune rose bushes. For details on exactly how, why and when to do this, visit here.  This is weather dependent so watch for low temperatures and delay if a cold snap is predicted.
• Remove broken branches from trees and clear dead leaves and decayed fruit from the base.
• If you’re looking to plant a new tree, consider the Park People’s annual fruit and yard tree sale that begins April 20. Trees range from $50 to $80, and sales support the Denver Digs program. More details can be found here.  

Lawn Care

• Prep your mower, sharpening the blade as necessary and conducting other maintenance. Lawn mower blades should be sharpened at least once per season.
• If you use a pre-emergent weed product, apply in early April. For more details about how to use, visit here.
• Fertilize as desired, reading labels for proper application. Keep in mind that fall is the most important time for lawn fertilization. Applying only in the spring can mean excessive top growth and shallow root systems.

Perennial Beds

• Cut back perennial plants if this wasn’t done last fall, leaving 3 inches of the plant above the soil.
• Similar to your vegetable garden, the soil in these beds will also benefit greatly from compost, with the exception of native plants which generally prefer unamended soil.
• Pull emerging weeds now. Stay on top of them from the start.
• Divide overgrown perennials such as chives, sedum, grasses, phlox, daisies, hosta, etc. This will lead to healthier plants and better growth.

Other April Gardening Thoughts

• Assess garden supplies. Purchase or plan to borrow anything needed. Sterilize and sharpen garden tools.
• Empty any pots or containers still holding last year’s dead plantings. Clean and disinfect them to prevent disease in new plantings.

These pots need to be cleared of last year’s plantings, disinfected and filled with new soil for plantings. Photo: Molly Gaines

• Denver Water recommends waiting to turn on your irrigation until after the last freeze, typically in early May. Hand water until then.
• Sow wildflower and pollinator seed mixes.
• Prepare for frost, hail and other bad weather. Have sheets of plastic, old bedsheets and five-gallon buckets in easy reach for late-season snow or spring and summer hail. Remember the hailstorm that hit Denver late June last season?

Sad peas in a bed covered with hail. June 29, 2023. Photo: Molly Gaines

Springtime in Denver is special. I love watching new life slowly unveil itself. It’s a time full of promise, new beginnings and high anticipation of the color, flavor and textures around the corner. The more prepared you are in April, the more enjoyable your summer gardening season will be.

As always, if you have questions about plants, planting and any other gardening and yard related topics, visit the CSU Extension Yard and Garden website for tips.

Colorado Gardening Calendar for February 2024

By Margerie Hicks, CSU Extension – Denver Master Gardener since 2010

Blue fescue grass poking through snow at Denver Botanic Gardens. Photo: Margerie Hicks

February is one of the best months to enjoy the interesting patterns, textures, and shapes that dried grasses and perennials form in contrast to the snow. It is also a time to read or otherwise educate yourself about gardening trends and ideas. And finally, it is a time to complete the few but important tasks needed in February to prepare for the coming growing season.

Winter Interest

Autumn joy sedum keeps its color and form. Photo: Margerie Hicks

If you refrained in the fall from cutting down ornamental grasses, perennials with balls of seeds like echinacea, or plants that keep their color and form, you now have interesting winter patterns and shapes to enjoy. You have also helped provide shelter and food for wildlife, such as birds and insects.

If you don’t already have any sedum Angelina, make a note to plant some in the spring to enjoy next winter. It is a ground cover that is light green in the spring, yellow in the summer, and orange with green accents in the winter. It provides a wonderful splash of color in the winterscape.

Sedum Angelina adds multi-season beauty. Photos: David J. Stang, CC BY-SA 4.0 via Wikimedia Commons

Gardening Edification

• Expo: The annual Colorado Home and Garden Show runs from February 24^thto March 3^rd. Master Gardeners will be on hand to answer gardening questions at the large CSU Extension display. Be sure to stop by and say hi.
• Books: You may have some gardening-related books waiting to read on a cold winter night, but in case you want suggestions check out our earlier post,  Winter Reading for Gardeners.
• Websites: CSU Extension’s website offers research-based fact sheets and videos on a wide range of gardening topics. Additionally, the internet is filled with gardening information and pictures. The most reliable sources have an “.edu” extension on the address, indicating an affiliation with university horticulture/agriculture research.
• Gardening classes:  Local garden shops and the Denver Botanic Gardens offer classes on many topics that may pique your interest. You can also find a wide array of webinars offered by CSU Extension here.
• Take our reader survey:  We’d love your feedback and ideas for future posts. Find the survey here. Survey closes February 18^th.

February Tasks

Deep watering tool. Photo: Margerie Hicks

There are a few tasks that should be done and many that could be done this month. A good overview can be found in this Late Winter Garden and Lawn Care fact sheet. Key tips include:

• Water:  All trees, shrubs, and perennials will benefit from regular winter watering, especially those that are less than two years old. Water once a month on days when the temperature is 40 degrees or warmer with no snow cover. Click here for a fall and winter watering fact sheet that will make your efforts most effective.
• Mulch:  Woody plants benefit from mulch to preserve soil moisture. Rock or gravel mulch is useful in retaining heat. Apply as needed.
• Prune:  This is a good time to prune broken and unwanted branches from trees and shrubs, especially fruit trees.

Enjoy your gardening leisure in February. May will be here soon enough.

Speaking of May don’t forget to mark your calendars for our amazing plant sale!

If Hail Strikes, Don’t Despair

Hail has been in and around Denver recently, so it seems fitting to re-run this 2016 post on a garden’s recovery from an especially bad storm. Hopefully you won’t experience damage, but if you do, you’ll find this helpful and encouraging.

By Mark Zammuto, Colorado State University – Denver Extension Master Gardener since 2010

Gardening along the Front Range of Colorado is not for the faint of heart. We have to deal with poor soil, wild temperature swings, intense sun, a short growing season, and hail. Somewhere in the Denver Metro area, someone will experience the heartbreak of hail this season. It is hit or miss from year to year, but it is inevitable. The results can be devastating. In a few minutes, a gardener’s hard work can lay in ruin.

The first thing to remember when you experience hail damage is not to panic or lose hope. That is hard to do when everything in your garden has been shredded to confetti.  The initial inclination is to give up for the year and pull everything out. Don’t do it. Take a deep breath and stand back. Some plants may be done for the year, but others will come back even if they look terrible right now. Plants want to grow. They have an amazing ability to come back.

In 2015, our garden experienced two severe hail storms: one at the beginning of June and one during the last week of June. We knew that most of our perennials would come back with time, but our vegetables were in a sorry state. Most were reduced to green sticks with a few tattered leaves hanging on for dear life. At that moment, it was hard not to throw in the towel for the season and head to the farmer’s market for produce.

After much wailing and hand wringing, we went out in the garden and cleaned up the dead plant material. We took care to leave any foliage that looked like it might have a bit of life left. Then we waited. Within a week or so, our tattered vegetable plants showed signs of renewed growth. Soon they were leafing out with abandon.

We helped them along with light applications of liquid kelp fertilizer. By the end of July, we were harvesting vegetables from the same plants we thought were lost in June.  It was not our best harvest, but it was very good given the challenges we faced.

One small confession – we did buy a few new plants to hedge our bets. It was late in the season to buy vegetables at the garden center. The selection was not great.  The replacement plants got a late start and needed to get established. In the end, the replacements did not do as well as the original plants. Although the foliage on the original plants was shredded, those plants had been in the ground for over a month and had strong established root systems.  It’s not always what you see above ground that matters most.

If you have the misfortune this season to be hit by hail, remember:

• Don’t panic.
• Clean up the dead foliage.
• Leave foliage that still has life.
• Do light applications of fertilizer.
• Be patient.
• Find more information on assessing hail damage here.
• Click here for tips on coping with hail damage to trees.

Colorado Garden Calendar – December 2022

Photo: Jodi Torpey

By Linda McDonnell, CSU Extension – Denver Master Gardener since 2013

Gardening slows down in December but doesn’t stop completely. There’s still time to finish some chores from our November list, so be sure to revisit it. For the next few months, prioritize winter watering during dry spells to ensure healthy plants next year.

December’s also a great time to enjoy indoor plants, appreciate nature’s seasonal beauty, and start thinking about next year’s garden.

Here’s a run-down of tasks and activities for December.

Trees, Shrubs, and Perennials

• Winter watering is essential to long-term plant health – make it a point to water during four-week dry stretches. To ensure proper absorption, water early in the day when temperatures are above forty degrees. This post offers excellent advice on when, why, and how much to water – and photos of the impact of too little moisture.
• To help with moisture retention, replenish mulch in areas that have gotten thin.
• Shake snow from bent tree limbs and branches to avoid breakage and lightly prune any broken limbs to avoid further damage.

Compost

• Continue adding green and brown materials to your compost bin. Since decomposition is slower in cold temperatures, break your materials into smaller pieces to speed up the process. The University of New Hampshire offers more winter composting tips here.

Thanksgiving cactus approaching its fourth decade & going strong. Photo: Linda McDonnell

Houseplants

• Winter is the dormant season for non-blooming indoor plants. Reduce watering, stop fertilizing, and keep them away from drafts for the next few months.
• Increase humidity around your plants. Ignore popular advice to mist with a spray bottle – to make an impact you’d need to mist for hours on end! Instead, group plants together on a pebble-lined tray and add water to just below the top of the pebbles.
• Check regularly for pests such as mealy bugs and spider mites. If present, treat and quarantine the infected plant. Find remedies here.
• ‘Tis the season for holiday plants and live Christmas trees. Here are some helpful links to keep them at their best: Keeping the Ho Ho Ho in Holiday Plants, Tips for Caring for Your Christmas Tree, A Year in the Life of an Amaryllis, and Christmas Cactus Care.

Celebrate, Inspire, and Explore

• The winter solstice arrives on December 21^st. In the Northern Hemisphere, it marks the day when the sun is at its lowest height at noon as well as the shortest day of the year. Starting the next day, we’ll gain about two minutes of daylight daily till June 21^st. Yippee!
• Share your enthusiasm for gardening with a child – find a few activities here or wander the library aisles to find an inspiring book on plants or nature.
• Check out 2023 seed introductions from your favorite growers. It’s time to start scheming and dreaming about next year’s garden.

As always, CSU is available to help with gardening advice at the CSU Extension Yard and Garden website. We hope you’ll visit often.

We’ll be back in two weeks with our last post of the year. Until then, enjoy all the season brings.

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. 

Gardening With Seasonal Allergies

Pixabay.com

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

No More Buds? Turn to Earbuds.

By this time in the year, I’m at the point of good riddance! with the weeds and careful tending (shout out to this cold spell for sealing the deal). Pretty much everything is done and put to bed. I then spend the next two weeks really dialing into my houseplant game before I get bored and start Spring dreaming. My Fall break from the garden is short-lived so I start listening to old episodes of now-defunct podcast series and dream with new ones.  Here are a few of my favs:

Gardenerd Tip of The Week

Gardenerd.com is the ultimate resource for garden nerds. We provide organic gardening information whenever you need it, helping you turn land, public space, and containers into a more satisfying and productive garden that is capable of producing better-tasting and healthier food.

https://gardenerd.com/

My thoughts: The host lives in LA, so this one is great for winter listening as we get chillier, I love hearing about the warmth of Southern California and what’s coming into season. Interviews with other experts and educators in the horticulture field discussing plants, but also cultivating grains, discussing bees, and seeds. Each episode ends with the guest’s own tips, many of which are news to me and have been incorporated into my own practices. 

On the Ledge

I’m Jane Perrone, and I’ve been growing houseplants since I was a child, caring for cacti in my bedroom and growing a grapefruit from seed; filling a fishtank full of fittonias and bringing African violets back from the dead.

https://www.janeperrone.com/on-the-ledge

Houseplants, if new to the podcast start here for an overview, and guidance.

Jane is a freelance journalist and presenter on gardening topics. Her podcast has a ton of tips for beginners, and more advanced info for longtime houseplant lovers, as well as interviews with other plant experts. The website is also useful to explore the content of an episode if you aren’t able to listen. I could spend an entire morning traveling in and out of the archives. 

My thoughts: As the growing season comes to a close, my indoors watering schedule starts wobbling between what the plants need and my summer habits of watering too many times per week–welcome back,  fungus gnats! Here’s an entire episode on them

Plant Daddy Podcast

We aim to create a listener community around houseplants, to learn things, teach things, share conversations with experts, professionals in the horticulture industry, and amateur hobbyists like ourselves. We also want to bring the conversation beyond plants, since anybody with leaf babies has a multitude of intersectional identities. We, ourselves, are a couple gay guys living in Seattle, Washington, with a passion for gardening and houseplants. A lot of our friends are the same, though each of us has a different connection, interest, and set of skills in this hobby, demonstrating a small amount of the diversity we want to highlight among plant enthusiasts.

https://plantdaddypodcast.com/

My thoughts: Plants are visual, podcasts are auditory- episodic overviews with links to viewable content available on their website. Are you also seeing Staghorn Ferns everywhere? They have an entire episode (photos included!) on the fern and how to properly mount it for that vegan taxiderm look. Matthew and Stephen are self-identified hobbyists with a passion for plants all the way down to the Latin–it’s impressive.

Epic Gardening

The Epic Gardening podcast…where your gardening questions are answered daily! The goal of this podcast is to give you a little boost of gardening wisdom in under 10 minutes a day. I cover a wide range of topics, from pest prevention, to hydroponics, to plant care guides…as long as it has something to do with gardening, I’ll talk about it on the show!

https://www.epicgardening.com/

My thoughts: The Netflix-episode-when-you-just-don’t-feel-like-a-movie kind of podcast. Addresses the best varietals, composting, soil pH, and troubleshooting some common issues in the garden. With daily episodes archived back to December 2018, there is a quickly digested thought for some of your own curiosities. The website is also a wealth of knowledge. 

Eatweeds Podcast: For People Who Love Plants

Eatweeds: An audio journey through the wonderful wild world of plants. Episodes cover modern and ancient ways wild plants have been used in human culture as food, medicine and utilitarian uses.

http://eatweeds.libsyn.com/

My thoughts: most recent episode (and appropriately timed!)  On edible acorns. My fav topics include foraging and wild yeast fermentation; and when I really start missing the Pacific Northwest, The Wild and Wonderful World of Fungi sends me back to a misty forest wander politely decorated by les champignons. Posting of this pod is sporadic–only 25 episodes since 2014.

You Bet Your Garden

(no longer on air, but archives available)

 

You Bet Your Garden® was a weekly radio show and podcast produced at WHYY through September, 2018. The show’s archive is available online. It was a weekly syndicated radio show, with lots of call-ins. This weekly call-in program offers ‘fiercely organic’ advice to gardeners far and wide.

https://www.wlvt.org/television/you-bet-your-garden/

My thoughts: Host, Mike McGrath, spends much of the show taking calls and troubleshooting, reminiscent of another public radio behemoth with Click and Clack, the Tappet brothers. McGrath incorporates a lifetime of organic gardening tips with humor. McGrath features one tip to find a local “rent a goat place” (no joke) to get goats to eat the most troublesome weeds to a concerned caller considering setting much of her yard on fire.

Cultivating Place: Conversations on Natural History and the Human Impulse to Garden

Jennifer Jewell, the founder of Jewellgarden and Cultivating Place, achieves this mission through her writing, photographs, exhibits about and advocacy for gardens & natural history and through her weekly public radio program and podcast Cultivating Place: Conversations on Natural History and the Human Impulse to Garden, on gardens as integral to our natural and cultural literacy.

https://www.cultivatingplace.com/

My thoughts: sort of like On Being, but for gardening.

A fav episode:

If you aren’t so sure about this podcast thing, and just want a place to start, start here.

Do you really need a brain to sense the world around you? To remember? Or even learn? Well, it depends on who you ask. Jad and Robert, they are split on this one. Today, Robert drags Jad along on a parade for the surprising feats of brainless plants. Along with a home-inspection duo, a science writer, and some enterprising scientists at Princeton University, we dig into the work of evolutionary ecologist Monica Gagliano, who turns our brain-centered worldview on its head through a series of clever experiments that show plants doing things we never would’ve imagined. Can Robert get Jad to join the march?

https://www.wnycstudios.org/podcasts/radiolab/articles/smarty-plants

A Denverite Visits New Orleans in July, Leaves in Awe That Anything Grows in Colorado, Like, Ever.

Image by McKenna Hynes

I recently returned from a little summer vaca in the South. New Orleans in July (a questionably timed vacation, albeit) is showy and fragrant; the ferns suckle lovingly to any crack and crevice providing green brush-strokes and blots everywhere, palms fill beds and pots alike, all of my houseplants are thriving in the wide open, the sun is scorching, and as our pilot reminded us as we prepared to de-plane, its humid enough to confuse a frog. I was constantly amazed at how effortlessly everything seemed to grow.

While in New Orleans, I was frequently amused by how the rest of the country (mis)understands Colorado living conditions. For the most part, folks think we spend most of the year dreaming of gardens as we stare out our frosty windows waiting for the snow to melt, visiting floral places abroad, and wearing multiple layers of socks at all times. Soooo… basically gardening at 10,000+ feet? While these perceptions are laughable, I started thinking that even though we don’t live in perpetual wintry wonder, the challenges we face to make anything grow aren’t necessarily less surmountable than our fam in the lofty-actual-mountains.

We were welcomed back to Denver with a remarkable storm featuring lightning, torrential rains, booming thunder… and hail. Of course, the very next day was smokin’ hot with nary a whisper of the siege.  Maintaining a vibrant garden in the Front Range is an extreme sport with our baffling daily fluctuations; the entire notion of keeping anything alive here seems impossible at times, but we’ve gotten pretty good at strategizing. Here are a few resources I’ve tracked down this year to help us all maintain beauty, build our skills, and be stewards to our land and community.

Image by McKenna Hynes

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Resource Central is a nonprofit organization based in Boulder that helps communities conserve resources and build sustainability efforts simply and cost-effectively. Their water-saving initiatives include native plant sales with simple designs for home gardens and often include low water perennials. They also have a tool library in Boulder where you can borrow for a couple of bucks per day so you don’t just buy the tamper, hedge trimmer, turf roller, or post hole diggers you need so infrequently. 

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The cities of Boulder, Lafayette, and Louisville partnered with Resource Central to give customers a Garden In A Box for turf-removal. Their Grass to Garden initiative is available to all communities with tips and resources to convert high water-consuming turf to low water garden areas. For the North Metro area, they have resources for assistance removing and disposing of turf, landscape architect recommendations, and more.

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Denver Water coined one of our most successful water-wise strategies with xeriscaping. And to keep sharing the good water word, Denver Water also partnered with local landscape architects to provide us mere civilians with some FREE! FREE! FREE! creativity. For those of us who are new (it’s me) who struggle with vision (all me), and are easily overwhelmed by the thought of starting fresh with a blank canvas (still, totally, all me), they’ve curated a bunch of plans for a variety of situations. They have plans for sloped xeriscaping, budget-friendly xeriscaping, narrow bed xeriscaping, year-round beauty designs, and many more. July is also Smart Irrigation Month! Head to Denver Water for tips on maintaining irrigation systems, watering rules, and efficiency strategies.

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And for the grand finale top-notch gardening game-changer, check out Plant Select for all your future dreaming. Plant Select is a nonprofit partnership between Colorado State University, Denver Botanic Gardens, and professional horticulturists to identify smart plant choices for the Rocky Mountian Region. Their mobile-friendly site has a tool to help you find plants that will suit the conditions you’re facing. I tend to challenge the tool to see how obscure or specific I can get, and it always provides me with something unique and gorgeous. Plant Select: taking “right plant right place” to an accessible and fun platform. Say So Long! to the multiple Google tabs researching the same plant with contradicting information on each site; Goodbye! Big Box Store swindlers promising “You REALLY can’t kill this one!” and go get yourself some good, wholesome, ACCURATE information quickly and easily from Plant Select. They also feature some garden designs and ideas.

Image source

By McKenna Hynes

Apprentice Colorado Master Gardener since January 2019

Creep

After a few wild weather days in my garden, yesterday morning I was out assessing hail damage to my new perennial bed and dahlias when I spotted a metallic bronze and turquoise body perching on one of the unshredded dahlia leaves. For a moment I marveled at the size of the beetle–much larger than I expected–and then the color and pattern. So lovely and kind of mesmerizing. And then it hit me. I’ve been heeding the warning of the onslaught of the Japanese beetle (Popillia japonica) but had yet to see one with my own eyes. Frankly, I couldn’t remember what they looked like or where they like to hang out, except that they are badbadbad.

Image via McKenna Hynes

I managed to snag two fairly mediocre photos and then took a quick swipe at it into a bowl of soapy water AND MISSED! It seemed to vanish into thin air! It had been sitting and sunning NOT nibbling on the luscious leaf unto which it perched for seemingly ever, and the moment I gave it a little nudge to its sudsy impending doom, it disappeared. Cursing, bewildered, picking, and digging madly, no dice. 

Meanwhile, my wife is watching this ridiculous mission at six in the morning from the front stoop with her first cup of coffee and casual observance of just another peculiar garden act (she literally has footage of me scrambling to plant “just one more” seedling well after dark with a headlamp affixed to my noggin). She is curious, patient, surely entertained, and finally asks what I’m doing.

I explained to her the grave danger our flora faces and that the invaders have arrived. I showed her a photo of the insatiable beast to formally introduce the target. I did my best to order her into the cause. There are bowls of soapy water conveniently located throughout the premises, I flag to her with my best flight attendant gestures. She is charged with taking immediate action, and regular surveillance of all the beds. The alarms are sounding!

Fortunately, this is not a new issue in our area. We covered the arrival of the Japanese Beetle in 2018 and continue to reference the fact sheet from CSU to prepare you for the onslaught. According to the Colorado Department of Agriculture, the Metro Area has a high population level of the Japanese beetles comparatively to the rest of the state, due to water usage and higher moisture levels in residential areas. The Japanese beetle doesn’t love our dry arid climates but thrives in our commercially and privately maintained lawns and gardens that use external sources of water to imitate a moist and humid environment for the beetle to thrive.

Integrated pest management strategies can help prevent the Japanese beetle from settling into your garden area,  including picking them off individually, reducing water in turf areas where they lay eggs and their larvae grow big and strong and demolish your lawn, selecting less appetizing foliage, and even getting chickens or ducks! Also, Party with a Parasite presents the Tachinid fly, a parasite that lays their eggs on a living host– a la JB–which hatch quickly and get to feeding. Cue: Bye Bye Beetle, Bye Bye. I’m not sure how to recruit this insect to the yard but will refrain from swatting at this time, just in case. Please use caution, good judgment, and safety when reaching for chemical management strategies by using only according to the label, and educating yourself on possible collateral damages; what else might be impacted by the use of this product?

I’ve been checking each plant several times since yesterday morning and have not seen another invader. My wife, on the other hand, casually mentioned last night that she saw one. It was so pretty. Was it in the Dahlias?! Yeah. Did you plunk it into the soapy bowl??? No. 

Sigggghhhhh. My attempts at recruiting more defenders are plighted. New strategies underway. 

By McKenna Hynes

Apprentice Colorado Master Gardener since January 2019

Why Leaves Linger

Here we are in mid-January and  most deciduous trees and shrubs (excluding conifers) have shed their leaves. But long after the last frost and through a couple of modest snow storms, there are still trees around the front range with leaves that are stubbornly hanging on, as you can see from the photos I took in my neighborhood last week.

Marcescence is the retention of dried, dead leaves during the winter. Typically, as woody plants prepare to shed their leaves in the fall, cells at the junction of the twig and the leaf petiole (stem) release enzymes and form an abscission layer, which aids in the separation of the leaf. Marcescent leaves do not develop this thin-walled cell layer and therefore, do not drop readily.

Early severe cold weather can cause marcescence as the development of the abscission layer is halted and the leaves do not release. Front range gardeners will recall an extreme case in November 2014 when an exceedingly mild fall was interrupted by a one day temperature plunge from a high of 58 degrees to a low of 16 degrees. The result was subsequent damage and loss of many hardwood plants the following season and beyond.

Some plants are more apt to hold leaves longer, including several oak species, hazelnuts, American lindens and beech trees.  According to Jim Finley of Pennsylvania State University, “Marcescent leaves are often more common with smaller trees or more apparent on lower branches of larger trees, which in forest conditions would be growing beneath taller trees where the reduced sunlight might slow the abscission process.”  Lower leaves are therefore exposed to cooler temperatures, resulting in leaf retention. It should be noted that upper leaves can also exhibit marcescence.

Marcescent leaves eventually drop, either due to wind, snow load or the push of new spring growth. Under normal circumstances, marscence does not damage trees.

References:

“Winter Leaves that Hang On”, Jim Finley, Department of Ecosystem Science and Management, Pennsylvania State University.

Written by Linda McDonnell, a Denver County Master Gardener