2024 Denver Master Gardener Plant Sale – Saturday, May 18 & Sunday, May 19 2024 – An All-Weather Event You Can Count On!

By: Lori Williams – CSU Extension-Denver Master Gardener since 2016

The 2024 CSU Extension Denver Master Gardener Plant Sale features more than 150 of varieties of perpetual vegetable winners, including a huge selection of hybrid and heirloom tomatoes, delicious culinary herbs, and more than 25 chile pepper strains (sweet, hot, sweet-hot, hot and hot-hot)! For a full list of what will be offered, visit here. We offer gorgeous, healthy plants for your garden: many you’re likely familiar with and some fun new ones to get your garden possibilities growing! All veggies and herbs are $7 each. Annual flowers will also be available. Come early for best selection. Bring your own flat or totes if you can!

Renata Hahn, pictured here, is among the 50 volunteers who grew more than 150 plant varieties from seed (that’s 10,000+ plants!) for the plant sale!

With planting time just around the corner, many gardeners are looking forward to getting into the soil and chocking it full of robust bedding plants. Volunteers will be on hand to advise on varieties, planting practices and gardening in general – Ask US!! When you take your baby plants home from the sale, here are some important tips to first harden them off, as they will be fresh out of the greenhouse.

An exciting addition to the sale this year is a native plant selection. Five different species will be offered for $9 each, including: Large-Flowered Penstemon, Switchgrass, Mexican Hat, Butterfly Weed, and Evening Primrose. These are expected to go fast! With each plant purchased, native seeds will be given away (while supplies last). Salegoers can view a native garden planted last season, and the Front Range chapter of WildOnes.org will have a table.

Also during the sale, you’ll enjoy gardening demonstrations and an “Ask a Master Gardener” booth for your gardening questions. CSU Extension will have research-based resources for home gardeners, as well as education and nutrition information. New this year, Denver Master Gardeners will sell seeds for cool-season crops (like peas and spinach that can be direct sown).  A selection of native plants and perennials will also be offered!

Do you garden in containers or raised beds? Interested in interplanting veggies, flowers and herbs? Maybe you’ve been curious about block style garden layouts? Community gardens offer great gardening options, too. Our partners at DUG have all kinds of useful information here. Fresh vegetables and herbs will make you glad for the space and time you spend this season on growing fresh, flavor-rich, nutritious food for you and your loved ones.

Find all your faves & diverse new selections.

Denver Master Gardener volunteers are heroic in their commitment to get the healthiest, prettiest seedlings to YOU for your 2024 growing season – no matter the weather! A Colorado spring day can bring rain, sleet, snow, and sun – in no particular order. Regardless of temps, winds, or precip, our volunteers are excited to get these lovely bedding plants into your hands. We will be there, ready to help you! 

We look forward to seeing you May 18 & 19!

Maybe you’re also interested in becoming a Colorado Master Gardener? Come grow your experience and learn about the many gardening options, being a Master Gardener, and the amazing resources available to you through CSU Extension! 

Natives, Nativars, and Genetic Consequences

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

A LITTLE BACKGROUND ON THE SUBJECT

The question of whether certain gardening practices help or harm the natural world has become a major consideration in recent years. Consequently, gardeners have adopted strategies to support our ecosystem, especially by including native and adapted plants to foster genetic diversity and the flourishing of local mammals, birds, and insects. These creatures, having evolved alongside our native plants, are attracted to natives for food and protection, while spreading the pollen necessary for the plants’ seed production and propagation.

Gardeners’ enthusiasm for the use of natives has sparked the production and sale of this class of plants through catalogs and nurseries and its promotion in gardening literature.  Where once only new varieties of old standards were garden possibilities, we now have expanding availability of natives. Add the general concern about climate change and sustainability to the mix, and we’re pretty much sold on this class of plants!

When a new class of sexy plants bursts upon the market, the demand is ever-increasing and intense. There also aren’t enough true natives in a sufficient variety to fulfill our cravings for unusual colors, sizes, foliage, and blooms. Given this, huge numbers of native plant cultivars – known as “nativars” – have emerged to fill the gap. This seems like a textbook operation of market forces, except for one thing: the effects of planting nativars on our cherished natives and, by extension, on the entire ecosystem are big, big unknowns.

LET’S DEFINE SOME TERMS

Before getting into the tall grass on this question, we’ll add some definitions:

• “Native” refers to a plant that was growing in the Americas before widespread European settlement, which began about 200 years ago.
• “Cultivar” designates a plant selected and bred for certain traits that is (usually) propagated by cloning. Many are the results of crossbreeding between species and (sometimes) genera.
• A “nativar” is a cultivar of a native plant that often produces sterile flowers (and therefore won’t reseed itself). It’s usually identified by genus, species, and a cultivar name in quotes, e.g. Physocarpus opulifolius ‘Red Robe,’ as opposed to the native ninebark, known as just plain Physocarpus opulifolius.

A FEW THINGS TO THINK ABOUT

Natives have been growing and evolving alongside their pollinators and other wildlife without human intervention for millennia; plants, animals, and insects have formed a nice symbiosis that supplies all involved with sufficient food, shelter, and opportunities to reproduce. But now humans are introducing new factors into ancient relationships that may affect our ecosystems in unknown ways for a long period of time. Gardeners should therefore think carefully about the desirability of introducing nativars created by unnatural means into a natural environment.

Popular horticultural literature and educational programs haven’t addressed this issue, but organizations devoted to best horticultural knowledge and practices have compiled science-based publications (including extensive reference lists) that shed a great deal of light on the pros and cons of using nativars in home gardens.

Let’s examine seven misperceptions about nativars, courtesy of the Maryland Cooperative Extension:

• It’s always bad to use nativars. Nope. Sterile nativars (look for blossoms that lack stamens) aren’t harmful, and some nativars are being bred for disease and pest-resistant features.
• The number of plants in cultivated gardens is outnumbered by natives in the wild. Numbers don’t necessarily translate into impact. And wild areas often occupy much less land than developed areas.
• Urban nativars can’t interbreed with natives in natural areas. Wind-borne pollen can travel a long way, and some pollinators are migratory.
• Adding nativar genes into native populations increases genetic diversity. This might be true if diversity is adaptive, not random (as with plants introduced by humans). And a nativar bred for higher vigor can compete with natives to the detriment of the latter.
• Plants’ performance is best measured by how often they’re visited by pollinators. Disruption of the natural balance cancels out perceived advantages of increased visits.
• Nativars created by spontaneous mutations (“sports”) don’t affect the ecosystem. Sports can be produced by recessive genes resulting from inbreeding, and random mutations lack the adaptability characteristic of native plants.

RESOURCES

CSU Extension takes no position pro or con concerning nativars, but I’m offering some helpful online resources below for further research. And of course, Denver County Extension stands ready to assist with information about this and any other horticultural concern!

Native vs. “nativar” – do cultivars of native plants have the same benefits?

A Guide to Native Plants: Straight Species vs. Nativars

The Nativar Conundrum: New Research on Natives vs. Native Cultivars with Dr. Doug Tallamy

REFERENCES

Cultivars of Native Plants | University of Maryland Extension. (n.d.). Extension.umd.edu. https://extension.umd.edu/resource/cultivars-native-plants/

Keeping Nature Near. (n.d.). Grow Native! https://grownative.org

Winter Conifer Care for Year-Round Interest

By Terry Deem-Reilly, Denver County Master Gardener since 2003

Conifers! They occur naturally everywhere in Colorado (albeit less so at plains elevations under 6700 feet). And they’re everyone’s go-to tree or shrub for filling a hole in the landscape or adding hassle-free continuous color. They’re so numerous and large that we often forget that their successful cultivation requires more than finding suitably large and sunny spots for placement and marveling at their spectacular (and automatic) growth. There are, however, some steps to maintaining these gorgeous plants in the dryness and cold of Colorado.

First all, let’s define the term “conifer”: it’s basically a tree or shrub with needles that produces seeds in the form of cones. Find a thorough discussion of the division Pinophyta/Coniferophyta here.

Planting

A winter care routine begins with planting properly: take a look at CMG Garden Notes Tree Selection: Right Plant, Right Place before shopping for a tree or shrub. (This publication includes a link to the Front Range Tree Recommendation list.) Conifers generally prefer sunny sites and good drainage, but moisture needs vary by species. Determine how much watering you’ll need to do to maintain the health of your plant – including winter watering so be sure to consider access to a water source when selecting a location.

Next, make sure that the planting site is large enough to accommodate a mature plant; that cute Colorado blue spruce in its three-gallon nursery pot will eventually reach a height of 30 to 60 feet and require enough room for a 20-foot spread. Consider if a mature tree will interfere with power or water lines, or property access. Remember that winter dryness can take a toll on evergreens, so place it in a sheltered spot or take steps to prevent desiccation (more on that later). Mulching to keep roots cool and moist, especially during initial growth, is a must.

Selection

If you like the look of a particular species but can’t find enough room in your garden for it, look for dwarf varieties. If your planting options are limited to containers, check out Monrovia’s The Best Conifers for Containers (and How to Care for Them). If you’re planting in the ground but would like to stay strictly native, read the CSU Fact Sheet Native Trees for Colorado Landscapes (remember that natives have the advantage of NOT having to adapt to our growing conditions while they’re establishing themselves in the landscape).

Monrovia offers some good suggestions for selection, planting, and care in Your Complete Guide to Growing and Caring for Conifers (this is a commercial site, so be prepared to see lots of their stock!).

Initial Care

Once the plant is in place and (we hope!) flourishing, maintain care throughout the season as outlined in CMG Garden Notes Care of Recently Planted Trees. Consult the CSU Fact Sheets for Trees and Shrubs for specific advice on planting, pruning, watering, and diseases of conifers and other woody plants. Proper irrigation is especially important, so water when the soil around the tree is dry to a depth of one inch. Continue irrigation throughout the fall.

Winter Care

Needle desiccation in the winter months can occur at the Denver elevation when precipitation levels are low, and plants aren’t receiving supplemental watering. Water all perennial plants, trees, and shrubs to a depth of one inch when the air temperature is above 45F and the soil is unfrozen.

Be aware that not all needle desiccation and drop result from insufficient watering; many species shed needles naturally at periods ranging from one year to every 17 years. Deciduous conifers such as larch and bald cypress drop all of their needles in the autumn. If needles in the center of a tree such as a pine turn brown, that’s normal shedding, but browning at branch tips is a concern. Take a look at the CSU Fact Sheet Environmental Disorders of Woody Plants for more information on this subject.

Many Front Range gardeners love arborvitae and despair at their seemingly inevitable winter damage. Wrapping the plants in burlap and/or using a protectant like Wilt-Pruf® or CloudCover® can help, but as noted above, the best protection for vulnerable plants is proper siting. Plant arborvitae and other tender conifers on the lee (downwind) side of the garden, or next to a house or shed. Remember that plants can cope with a variety of situations, even temps of -15F and extended dry periods (with some help). Good luck with your winterizing!

Renovating a Native Plant Demonstration Garden

By Kathy Roth, CSU Extension – Denver Master Gardener since 2018

Denver Extension’s new Native Plant Demonstration Garden is in the ground! The old garden, installed in 2014, had fallen into a tangle of weeds and only a few native species remained. Given this, in May 2022, a group of interested Denver Master Gardeners decided to give it an overhaul and tasked themselves with brainstorming a new design. Their goal: showcase native plants that promote biodiversity, support pollinators and wildlife, and thrive in urban gardens.

Committee reviews initial design plans. Photo by Anne Hughes

The committee’s first order of business, using resources available from CSU Extension like this Fact Sheet and this publication from the Colorado Native Plant Society, was to determine what could be salvaged and what needed to be demolished. Field trips to demonstration gardens in neighboring counties fueled their knowledge. After discussion and research, they created a new design and planting plan.

^{Planting plan by Nancy Downs. Photo by Kathy Roth}

Next, the group made choices about installation. They decided against soil amendment, in part to avoid stirring up weed seeds, but also because natives do not require nutrient rich or high organic soils; natives grow successfully in unamended soil. For mulch, the group opted for squeegee. This was following Douglas County Horticulture Agent John Murgel’s compelling argument that rock less than 3/8” in size maximizes soil water penetration. 

Denver Extension is located in the city’s Harvard Gulch Park, so we were fortunate to get lots of help from Denver Parks and Recreation. Our start was delayed week after week by relentless spring rain which turned the site into a swamp. Finally, Jared McQueer, DPR Median Renovations Operations Supervisor, and his crew were able to demo and grade the site, construct the hardscape elements, and install irrigation. Surprisingly, we chose pop-up sprays instead of drip because DPR has had bad experiences with rodents damaging drip lines in city parks.

DPR crew demolishing site. Photo by Anne Hughes

Propagating and acquiring native plants can be a challenge. We lucked out because the partnership with DPR meant Holly Shields, DPR Greenhouse Supervisor, grew our plants in the City Greenhouse.

Plants staged in Extension Office. Photo by Anne Hughes

When skies finally cleared at the end of June, team member Dudley Clark kicked off planting week by coordinating construction of a temporary rabbit fence around the garden perimeter to protect the small plants from being devoured before they even got started. To our amusement, we discovered several days later that we had fenced in a rabbit! To everyone’s relief – including the rabbit’s – we corralled it and relocated it back to the park.

We used a planting technique called “bare rooting” to plant. Supposedly, it promotes immediate contact between soil and roots which translates to less transplant shock. For more on bare root planting, watch this video from Denver Botanic horticulturist Grace Johnson. 

Our planting crew. Photo by Anne Hughes

Volunteers checked the garden daily the first month to monitor water and to keep ahead of weeds. We’ve been lucky so far. There is some prostrate spurge, an annual weed that is easily pulled, but milkweed is a problem because although native, it spreads by rhizomes and quickly forms unwanted colonies.

We lost a few plants but not many. The Gambel Oaks have struggled the most and just when we thought they had adapted, something started eating the foliage. However, given how small the plants were and how hot it was the week we planted, we are amazed at how good everything looks and how quickly plants are establishing. We plan to leave the fence up through the winter but by next season the plants should be established enough to fend for themselves. 

Next up is signage. Our plan is to label plants and include QR codes that link to educational materials on the Denver Extension website. Come next spring, visitors will be able to see the garden’s progress and follow along through the seasons.

Denver Extension thanks the Denver Master Gardeners and the DPR crew for their help with this project.

Reducing Garden Maintenance

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

Except for those with a live-in gardener, we all want beautiful, lush gardens with little or no fuss and minimal effort. To achieve this, we need to plan for garden features and types of plants that eliminate some of the work. Here are three approaches to consider.

Apply Mulch to Control Weeds

If I were a poet, I would write an ode to mulch’s many useful properties. A layer of about three inches in beds will reduce maintenance by blocking out light and inhibiting weed germination. It also retains moisture to reduce watering needs.

Shredded bark mulch stays in place on this sloping garden bed. Photo by Margerie Hicks

There are various sizes, colors, and types of mulch available, depending on the purpose, location, and your personal preference. This CSU Extension fact sheet lists many varieties of mulch, along with the advantages and disadvantages of each. Some of the most common are:

• Wood/bark chips: Functional for many purposes.
• Shredded bark: Fibrous, coarse texture mulch made from finely shredded bark of redwood and western red cedar trees. It is useful on slopes as it reduces soil erosion and doesn’t wash away.
• Grass clippings: Functional in vegetable gardens where wood and bark mulches are not advised.
• Pea gravel: Besides weed control, it looks great in succulent and native plant gardens. It increases water infiltration and can improve the growth of perennials, especially in water-saving gardens.

Install Ground Covers 

Many ground covers form a thick layer that discourages weed growth. Over time the plants will spread and thicken for an increasingly better weed barrier. The many colors, textures, and sizes are aesthetically pleasing, too. This extensive list of ground covers is arranged by sun vs. shade and size of area to be covered and this list offers suggestions for shading loving, drought tolerant groundcovers. 

These groundcovers, described below, will spread to cover most of the bed’s surface in a few years. Photo by Margerie Hicks

Plants in the photo above:

• Hens and chicks form tight clusters of succulent rosettes; may have red and green hues.
• Ice plant ‘firespinner’ has succulent foliage covered with bi-colored orange and fuchsia blooms. Ice plants are available in many colors.
• Thyme ‘pink chintz’ is low growing with purplish-pink flowers.
• Dianthus ‘maiden pink’ produces single pink flowers above narrow foliage. Many dianthus varieties have the same thick weed barrier effect.

Others that combine weed barrier function and beauty:

• Turkish veronica is a low growing carpet-like ground cover with a profusion of tiny purple blooms.
• Sedum ‘Angelina’ has pleasing light green foliage in early summer; turns orange later in the season and into winter.

Eliminate or Contain Plants That Spread Rapidly

Many plants in this category may be plants you like, so you will have to weigh the advantage vs. the effort to control them. Just as mulch deters weed growth, it can also deter the unwelcome spread of some of these plants.

Russian sage whose spread is out of control. Photo by Margerie Hicks

Examples of plants that can become invasive:

• Mint gets out of hand quickly. Grow it in a pot that is at least 12 inches wide and deep to contain spread.
• Bamboo is a super spreader. Select ‘clump-forming’ varieties, which are usually less invasive than ‘running’ types. Create barriers if necessary or consider planting it in large containers and keep their size in check by removing unwanted new growth as soon as you spot it.
• Russian sage is a member of the mint family, spreads by runners and needs to be monitored to keep it out of places where you don’t want it. Pull up suckers in the early spring and divide the plants every four to six years to refresh them.
• Lamb’s ear can quickly overtake an area. If you like the soft silvery foliage, silver sage is an excellent substitute.
• Quaking aspen trees readily send out new plants from the root system. To grow a single quaking aspen as a specimen plant or shade tree, you must continually remove any new plants from the root system to avoid growing unwanted trees. Aspens are also prone to disease at the metro area’s elevation.

Many other plants could be included in this invasive category, depending on personal preferences. In fact, it is often said that a weed is any plant that is unwanted in a certain location. 

After you have accomplished some of these measures, be sure to appreciate your newfound time to spend on other gardening tasks or just sit back, sip some lemonade, and watch your garden grow.

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.

Planning a Garden for Thrills Spring to Fall

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

One of the most satisfying aspects of gardening is seeing dormant sticks, clumps, and bulbs that were placed so hopefully in the soil leaf, blossom, and fruit. At the same time, one of the most daunting aspects of gardening is ensuring that all of that leafing, blossoming, and fruiting doesn’t occur all at one time. A garden that ceases to bloom after the last tulip has disappeared or browns up from the fall equinox until the following spring won’t satisfy the senses nearly as much as one that displays continuous interest. Moreover, landscapes which produce pollen and nectar throughout the season provide important nourishment for pollinators.

Hellebores kick off the season. Pixabay.com

Other posts in this blog have stressed the necessity of matching plants to sites, soil, and sun exposure that will allow them to flourish. Horticultural considerations don’t disappear when the goal is season-long color and interest; selecting plants that like the same conditions and grouping them into the areas where they’re most likely to flourish are indispensable to having the three-season garden of your dreams.

The detailed first steps to success with any perennial garden can’t be adequately covered here but are well-explained in the Extension fact sheet Perennial Gardening. Remember the conditions in your site when reviewing plant lists.

Next, consider whether you’d like to include non-native or xeric/native trees, perennials, and shrubs; this decision will determine the amount of time and attention (not to mention water) you’re going to devote to a three-season garden. Xeric plants and Western natives won’t need much maintenance after the first season or two, but a lush English-style bed of roses, delphiniums, and pinks demands careful soil amendment and regular irrigation, mulching, and fertilization. Decide what look you’re after and what it will take to achieve it.

Mid-summer morning & the garden’s in full bloom. Photo: Linda McDonnell

To make plant selection a little easier, here are suggestions from plant lists showing seasonal bloom by non-xeric and xeric/native varieties, with links to the complete lists for easy reference.

Nonxeric or Non-Native Perennials

• Spring: early blooming bulbs, primrose, candytuft, viola, creeping phlox, hellebore, peony, geranium
• Summer: garden phlox, dianthus, lily, verbascum, hosta, campanula
• Fall: aster, chrysanthemum, Japanese anemone, lobelia

For the complete list, see the Plan Your Garden with our Perennial Flowering Plants by Season Guide. Some of the plants shown above also appear in 25 Perennial Flowers That Bloom From Spring To Fall. Timberline Landscaping in Colorado Springs has published a bloom calendar of perennials that do well on the Front Range.

Xeric and/or Native Perennials

• Spring: early blooming bulbs, columbine, amsonia, windflower, pasque flower
• Summer: chocolate flower, poppy mallow, asclepias, eriogonum, penstemon, oenothera
• Fall: helianthus, asclepias, winecups, hyssop, agastache

These plants, and many others, can be found in these Extension fact sheets: Native Herbaceous Perennials for Colorado Landscapes and Xeriscaping: Perennials and Annual Flowers. These resources also indicate water needs, light requirements, and plant heights and descriptions.

Want to see more native plants? CSU’s Low-Water Native Plants for Colorado Gardens: Front Range & Foothills includes not only common and botanical names; height; color, size, water and sun requirements; and wildlife value, but also design plans and photos of great local native gardens. Mountain residents will find the Extension fact sheet  Flowers for Mountain Communities useful for plant selection and advice on cultivation.

Shrubs and Trees

Hawthorn tree in fall. Pixabay.com

Our guide wouldn’t be complete without recommendations for suitable trees and shrubs to supplement your perennial display. Many plants in these categories offer blossoms, fruits, and/or color that add interest throughout the season; a number of them offer all three!

Here are examples of shrubs that add color and interest through the seasons:

• Serviceberry
• Fremont mahonia
• American plum
• Buffaloberry
• Western sand cherry

For a complete list, consult the Extension fact sheet Native Shrubs for Colorado Landscapes. Again, you’ll see botanical and common names, size, and sun, moisture, and sun requirements for each shrub.

Some trees that add interest include:

• European mountain ash
• Pine
• Colorado blue spruce
• Aspen (Foothills and submontane areas only!)
• Maple

See the fact sheet Native Trees for Colorado Landscapes and the CSU publication Recommended Trees for Colorado Front Range Communities for more details. Mountain gardeners should consult the fact sheet Trees and Shrubs for Mountain Areas for suggestions.

Finally, don’t discount the value of roses when planning for season-long color. Even with the plague of the Japanese beetle, roses (especially hip-bearing and species roses) dependably add color through the growing season. The Denver Rose Society publishes a list of the best roses for our climate: Recommended Roses for Colorado.

If problems arise, always, ALWAYS rely on research-based information to answer your questions;  Denver Extension stands ready to help!

Experimenting with Winter Seed Propagation

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

 I hope my winter experiment yields beautiful Echinacea plants this summer! Image: Flickr

I’m a fan of the gardening podcast “A Way to Garden” hosted by Margaret Roach, columnist for The New York Times. Recently she interviewed Heather McCargo, founder of the Wild Seed Project, a horticulturist-supported non-profit based in Maine. The organization is committed to building awareness of native plants, the importance of increasing biodiversity, and ethical seed collection. Find the full interview here.

Their discussion of outdoor winter seed sowing really piqued my interest. Had I ever given much thought to winter sun, precipitation and temperatures being necessary for native seeds to germinate? Honestly? No. 

The suggested timing for winter seed propagation – start after the holidays – also caught my attention. It all sounded pretty simple. Start by gathering on-hand garden supplies and seeds collected from my yard and other gardeners and find an appropriate winter location for the pots to live. The genuine bonus of growing a few of my own perennials was just too intriguing not to try. I was inspired!

Everything needed for winter propagation of seeds that not only survive winter but germinate because of winter. Photo: Lori Williams

Materials

• Containers roughly 4-8” wide, avoid biodegradable pots as they will likely break down in winter weather.
• Seeds – discover germination guidelines and other seed information for Colorado here.
• Organic, compost-based potting soil is recommended because it’s filled with different microorganisms. Please note, compost is not recommended for Colorado native plants as they prefer a ‘leaner,’ less organic soil. Find info on propagating our regional natives here and in CSU’s fact sheet 7.242.
• Coarse sand to cover seeds after planting assists seeds in staying lodged in planting medium and allows light to reach them.
• Group containers, flats, etc. and cover with wire screen, anchored with bricks or rocks, for squirrel protection.
• Label pots to avoid forgetting what seeds were planted where. Pencil on plastic tags really does work best.

January 17th was 38℉ & partly cloudy, a cold breeze bringing in a big snow, I wanted my seeds to benefit from the predicted precip. Photo: Lori Williams

Location

• A level, shaded area for containers to endure winter undisturbed. Shade is essential during sunny, warm days so pots don’t overheat and dry out. Keep containers level so seeds don’t float or splash out during heavy precipitation.

Ethical Seeds

The Wild Seed Project stresses collecting and using seeds native to your location. Collecting native seed from public lands and in the wild (in Maine, Colorado, and most of the nation) is typically a huge no-no (AKA unethical) so how do we collect seeds ethically? 

• Seed from our own gardens are the easiest to collect. 
• The friendly approach of asking ‘May I gather a few seeds from your XYZ perennial? I’d love to try to grow it.’  
• Seed swaps are another excellent resource and a request on social media can produce great results. 
• Wild Seed Project and other ethical seed providers offer native seeds for purchase. 

Buy seeds suitable to your growing conditions, of course, and be familiar with what those plant seeds look like. As a newbie gardener, I planted dried Echinacea flower petals twice thinking they were seeds. 

My Project

While I did not have native seeds for my backyard experiment, I did have ethically collected seeds from non-natives. I planted three flats with Echinacea and lavender seeds from my garden and seeds from a divine lupine that was a volunteer in a friend’s yard. On January 17th I placed my pots in deep shade against the house with bricks holding the screen cover in place. That evening 6.5” of snow fell and temps stayed cold for weeks afterward. 

Snow covered since January 17^th, it took the snow on my flats until the end of February to finally melt. Photo: Lori Williams

Outdoor winter propagation is challenging for the impatient gardener (me) but my long game of possibly growing some perennials of my own from seed has me hopeful. With more Colorado snow and cold ahead, my flats remain undisturbed in the shade. I resisted the urge to water them during the last several weeks of no moisture – and then we had a welcome icy rain turning into snow – YES! 

As my flats have yet to show any noticeable growth, I am watching for signs of success during our longer days accompanied by the sun beaming from higher in the sky. 

Webinar Invitation: Doug Tallamy on Solutions to Insect and Bird Decline

Leafcutter bee on native sunflower. Photo courtesy of Lisa Mason

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

If the recent headlines about the serious decline in the bird and insect populations make you want to crawl under a blanket and hide, consider attending ecologist Doug Tallamy’s free virtual talk on December 1^st at 5pm MT. Sponsored by the Coalition for Endangered Species, the webinar will explore Dr. Tallamy’s research on the decreasing insect and bird populations and most importantly, what each of us can do to work towards a solution. Register in advance here.

A highly respected advocate for restoring native habitats, Dr. Tallamy is the author of the New York Times best seller Nature’s Best Hope, a professor at the University of Delaware, a sought-after speaker, and the co-founder of Homegrown National Park.  

Hope you’ll attend. Blankets optional.

This webinar is approved for Denver County Master Gardener educational credit.

Looking Forward: A Lower Maintenance Garden with Native Plants, Fruit Trees, and Shrubs

By Felicia Brower, CSU Extension-Denver Master Gardener since 2020

Now that the 2022 summer season is winding down, it’s a great time to review what worked in the garden and what didn’t and to start planning for next year. (Keeping a garden journal throughout the season saves time and makes this much easier!)

Start by asking yourself the following questions:

• What grew well this season?
• What didn’t grow as well as you would have liked? Any idea why?
• Did you struggle with pests or disease?
• What do you want to plant next year?

After you have the answers to those questions, you can begin to make a plan to fix any problems that popped up or to repeat your successes next season.

As far as what grew well in my garden this year goes, I planted more localized seeds this year because seeds bred for our specific climate tend to have fewer days to maturity and produce more drought-tolerant plants than ones grown from other seeds I’ve used. They fare better in my garden and will be a staple every year moving forward.

Photo credit: Felicia Brower

That being said, my garden got off to a rough start this year thanks to pest problems, extreme heat, and watering issues. Many of the seedlings I started inside were immediately eaten after being transplanted outdoors, and it seemed like no amount of diatomaceous earth could help. I wasn’t watering enough to combat the weeks of 100° sunny weather, and the growth of a lot of my vegetables suffered because of it. I was recently able to get things under control (better late in the season than never!) and my vegetables and flowers have finally started growing the way that I had hoped they would. I’ll be spending the winter learning more about Integrated Pest Management (IPM) and effective watering techniques to make the most of water during a drought.

As I look at what I’d like to change in my garden next summer, one big one is that despite loving it, I want to spend less time doing maintenance in it. I spent much more time weeding and trying to problem solve than I would have liked, and a few adjustments could make a very big difference.

The biggest change is going to be adding more native herbaceous perennials and fruit shrubs and trees in the yard. My hope is that by making the investment to fill out those open spaces, the weeds I spent so much time pulling will be unable to take over, and I’ll end up with beautiful, lower-maintenance native flowers, shrubs, and trees.

Here are a few of the plants on my list for next year:

FLOWERS

I usually plant vegetables and annual flowers, but after seeing the perennials that I planted last year pop up this year without having to start anything inside, I’m making a big shift to focus on native flowers and herbs that come back without any effort from me.

Blanket flower. Photo credit: Canva

Having perennials show up in the spring will add much-needed greenery to the yard after a cold winter, and I look forward to the pops of color they’ll provide throughout the summer and into fall. I can’t get enough of the vibrant red and yellow petals of blanket flower (Gaillardia aristata) and plan on adding some big patches of it to my garden next year. I’ll also be looking into adding more penstemon (Penstemen spp.) to the landscape. With more than 60 native penstemons to choose from, these easy-growers range in size from a few inches to a foot or two tall with long flowering spikes.

Chocolate flower. Photo credit: Canva

Chocolate flower’s (Berlandiera lyrata) yellow daisy-like flowers have a wonderful scent and typically flower from June until frost. Goldenrod (Solidago spp.) produces tall bursts of yellow blooms later in the summer, from August until November and is known for being easy to grow and care for.

SHRUBS

Shrubs, specifically ones that produce fruit, are going to take a lot of space in my yard next year. Drought-tolerant gooseberries and currants grow especially well in our area, and their berries can be eaten fresh or used to make delicious jams and pies.

Gooseberries. Photo credit: Canva

I have a raspberry patch that I plan on expanding to different areas of the yard. These prolific growers will take up a lot of space and provide delicious snacks while I’m out harvesting and fresh berries for some new recipes I want to try. Serviceberry is cold-hardy and drought-resistant, making it a no brainer for someone looking for a low-maintenance addition to the garden. The fruit also happens to be high in vitamins and is comparable to blueberries but with a slight apple flavor.

Serviceberry. Photo credit: Canva

TREES

Trees are a big investment and a lot of planning needs to go into which trees will be planted and where. For fruit trees, I’d like to plant plums, since they’re considered very dependable for this area, and a peach tree. Peaches can be a higher risk tree because late frosts can damage blooms and prevent peaches from developing, but I think it’d be fun to have a self-fruiting dwarf variety that can still provide shade and habitat for animals even when it’s not fruiting.

---

After planting all of the fruiting trees and shrubs, I’ll have an abundance of produce in my yard for years to come that I’ll be able to preserve and share with neighbors and members of my community through programs like Grow & Give. It’ll take a few years, but after everything’s established, I’ll only need to worry about planting my vegetables annually, which I also plan to scale back on…eventually. For now, my focus is on finding the plants that I want to get in the ground this fall and next spring, filling out the landscape, and learning as much as I can about how to help everything in my garden thrive.

—

Watch for future ‘Looking Forward‘ posts where we’ll spotlight Master Gardeners who are applying what they’ve learned to expand, rethink, or improve their gardens.