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! 

Colorado Gardening Calendar for May 2024

By Valerie Podmore – CSU Extension-Denver Master Gardener since 2020

This is the month we’ve been waiting for! May is the best month for getting your plants from the Master Gardener Plant Sale on the 18^th and 19^th and planting them, with the caveat that anything can happen weather-wise, so be ready…remember 2 years ago?

Vegetable Garden

• This is the time to direct sow hardy, cool season vegetable seeds such as lettuce, kale, and spinach.
• Plant your (newly purchased!) veggies and herb plants when nighttime temperatures are consistently a minimum of 50 degrees, and make sure to protect them with cover when temps drop below 40 degrees. This includes tomatoes, peppers, and eggplants.
• Consider your planting location, i.e. Rotating your crops to prevent bacteria that might have infected plants last year from doing so again.
• Weeding is essential as much as possible, so let’s get on it!

Trees and Shrubs

• Just in case May ends up being sparse in the precipitation arena, don’t be afraid to bust out your hose and give your trees a good soaking, watering deeply once per week.
• This is also a good month to prune trees to remove any dead branches from needed but possibly damaging snowfall.
• Mulching is a great way of helping your tree retain water, just make sure to keep it between 3-4” deep and about 6” away from the trunks so it doesn’t hinder healthy root development and allows the plant to take up moisture.
• Prune summer blooming shrubs that bloom on new growth, such as roses before they begin to flower. Refrain from trimming shrubs that bloom on old growth such as lilacs until after they flower.
• This information sheet has great pruning information.

Lawn Care

• This is a great month to aerate the lawn to loosen up soil for better water absorption, as well as removing thatch (tight, brown, spongy, organic layer which can cause problems down the road in terms of lawn health) when it becomes too thick.
• After aerating is a wonderful time to overseed your lawn to regrow any bare spots which have developed over time.
• Watering is important for lawns as for other plants as this month heats up. Of course, if there’s rain or snow, hold off.
• Watering in the late evening or early morning helps retain more water as the weather tends to be cooler and more humid at these times.
• This is the month to treat your lawn for Japanese Beetle grubs. Use products like GrubGONE! which has been shown to do a great job of stopping this pest before it leaves your lawn and infests your plants.   

Perennial / Annual Flower Beds

• Continue cleaning out the garden, including spent flowers and cutting back foliage to help perennial plants direct their energy to growing.
• Look at possible locations where plants might not have performed as well as desired and where you can fill in or move existing plants.
• Waiting until late May to plant annuals will give them a chance to survive any crazy cold spells, although there are many that will do well in cool weather, such as petunias and pansies.
• This is also a great time to plant summer blooming bulbs!

May is such a great gardening month, let’s take advantage it and grow, grow, grow!

Visit the CSU Extension Yard and Garden website (https://extension.colostate.edu/topic-areas/yard-garden) for more gardening tips.

Colorado Gardening Calendar for October 2023

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

October is my favorite month to enjoy the vibrant, intense colors and crisp autumn breezes of Colorado. Gardeners need to adjust their routines to ensure a healthy, beautiful garden next year by completing the maintenance tasks outlined here that apply to your garden.

Vegetable Garden

Harvesting carrots and beets photo by a-lesa on iStock

• Harvest and Preserve: Your vegetable garden may still be yielding some late-season treasures. Harvest your remaining root vegetables and squash. Store them in a cool dry place for use throughout the winter. Consider canning or freezing surplus produce or donating some to a food bank. For canning information click here. The first frost will probably occur mid-month, so don’t be caught harvesting one night in a freezing drizzle (I’m speaking from experience); observe the weather reports each day.
• Clean and Compost: Remove spent plants and weeds from your garden beds to prevent diseases and pests from overwintering. Compost healthy plant material to create nutrient-rich soil for next spring. Learn more about composting techniques here.
• Plant Cover Crops: Protect your garden’s soil during the harsh winter months by sowing cover crops like winter rye. These cover crops help prevent soil erosion, suppress weeds, and improve soil structure. When spring arrives, you can simply turn them under to add organic matter to your soil.

Trees and Shrubs

• Blow out the sprinkler system: When water freezes the pipes may crack.
• Wrap the trunks of trees that have been planted in the last one or two years:  Click here for details.
• Prune and trim: See this Colorado State Forest Service pruning guide. Do not prune spring flowering shrubs or you will be removing next year’s blooms. In the future, prune these soon after the blooms fade. 
• Irrigate: Continue to water, and plan for monthly watering all winter on days the temperature is above 40 degrees Fahrenheit.

Lawn Care

child playing in leaves photo by Scott Webb on Unsplash.com

• Rake leaves:  First form big piles so the children in your life can play in them. Then compost the leaves at home or take them, ideally in paper bags, to one of the leaf drop sites provided by the City of Denver. Click here for locations, dates, and times.
• Fertilize: Click here for details on proper lawn fertilization.
• Aerate: Unless your lawn has been aerated since spring, see the sub section of this fact sheet called “Core Cultivation or Aerating” to learn more.

Perennial Flower Beds

Planting tulip bulbs photo by LianeM on iStock

• Plant spring bulbs: Tulip, hyacinth, crocus, daffodil and other spring blooming bulbs can be planted when the weather gets cool. See this fact sheet for important considerations in selecting and planting bulbs.
• Divide and transplant: October is the ideal time to divide overgrown perennials. This process rejuvenates the plants and can also provide you with new additions to your garden. Transplant them to new areas or share them with fellow gardeners.
• Cut back and clean: Trim back faded perennial foliage and remove debris from your flower beds. Consider leaving some plants uncut, such as ornamental grasses and dried echinacea blossoms, as winter habitat and seeds for birds. These and other plants, such as Autumn Joy sedum, provide winter interest to the garden.

Annual Flower Beds

Ornamental Cabbage photo by Santi WiWatchaikul on iStock

• Plant cool season annuals: Extend the beauty of your garden by introducing cool season annuals like pansies, violas, and ornamental kale or cabbage. These hardy plants can withstand the cooler temperatures of late fall and early winter, adding vibrant color to your landscape.
• Enjoy blooms inside: Before the frost, cut any remaining blooms, such as roses, bring them in the house, and put in vases to enjoy the last summer color.

Other Tasks

• Bring in house plants from the patio before the inevitable frost. First, hose off the summer dust and any insects, then let them dry while still outside.
• Wash and store pots; clean, sharpen, and oil garden tools; store for the winter.

October is a transitional month in Colorado gardening. Use this month to prepare your garden for the winter months ahead. Remember to adapt these guidelines to your specific microclimate and garden conditions, and always consult research-based resources such as https://extension.colostate.edu/topic-areas/yard-garden/ for the most accurate advice. Happy gardening.

CSU Flower Trial Gardens, 1000+ Flower Varieties Trialed for 2023

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

Have you enjoyed or wondered about CSU’s campus Flower Trial Garden in Fort Collins? It’s a flower-lover’s paradise where 1000+ bountiful and bodacious annual and perennial flowers are performance tested annually. A team of evaluators recently reviewed this year’s entries, and the winners will be announced shortly. These champion flowers will be making an appearance near you soon!

Here is a sample of stand-out flowers from the 2022 trials.

What You’ll Find if You Visit

The Trial Gardens together with University Center for the Arts is called the Garden Arts District. Passersby, astute and curious gardeners, lucky students, staff and faculty enjoy the area routinely. The gardens are open for viewing through October. If you visit, you’ll find:

• Perennial Trial Garden is directly in front of the Center for the Arts building. Handsome perennial container trials stand in impressive rows.
• Perennial Demo Garden on the building’s north side is robust in color and texture.
• Vibrant rows and swaths of annual trials wind around the center park.
• Shade annuals are on trial under the stately, northern Shade House.
• Next to that, the All-America Selections® display and trial ground is showy and full.
• Plant Select’s Demonstration Garden, adjacent to the gazebo, features an outstanding array of plant, butterfly, and bee varieties.

All kinds of garden-y goodness abound at the intersection of College Ave and Lake Street in Fort Collins. Photo Lori Williams

You’ve likely seen a divine flowering something in a public garden that immediately and deeply dives into your heart, and you ask, “What is that?!” only to discover no label or information. CSU has signage noting plant name/species and variety at every planted grouping. It’s a wish-list maker’s dream come true! Obviously and absolutely essential for evaluations and voting.

Exceptional trial flowers with precise plant information posted for accurate voting and fun for Latin tongue twisting, too! Photo: Lori Williams

History, Mission and Trial Criteria

The Flower Trial Garden is a seriously revered testing ground for seed companies, industrial growers, and horticultural researchers. To learn more about the garden’s history, the evaluation process and how trial research and data are used, watch this short video narrated by Dr. Jim Klett, CSU Professor Emeritus.

Colorado State University’s overall mission is simple: to provide education, research and outreach to anyone with a desire to learn. The trial gardens are an exceptional example of the University’s commitment to this mission.

According to CSU, the purpose of displaying and evaluating performance of annual and perennial cultivars in Colorado’s unique environmental conditions “allows students, researchers, industry representatives, homeowners and extension personnel to learn, teach and evaluate through horticultural projects conducted in the unique environmental conditions of the Rocky Mountain/High Plains region.”

Trialing Cultivars: Will You Grow in Colorado?

Approximately 25 different companies submit seeds or rooted-cutting entries annually. Find criteria here.

Colorado industry professionals work with CSU ensuring trials are scientific and participants receive performance results.

Evaluation Day in early August involves Colorado Master Gardeners, community members and horticultural leaders evaluating and creating “Best Of” entries lists.

CSU promotes the “Best Of” varieties to growers and sellers, encouraging them to bring these winners to market.

What Makes a Winner?

Not all flower varieties can withstand Colorado’s unique growing conditions, which include high altitude, intense solar radiation, drying winds, severe hailstorms, large fluctuations between day and night temperatures and a season-long need for irrigation. Plants are closely monitored for their ability to withstand these factors. Perennials are trialed for three summers.

In addition, genetic changes have occurred during trials. With more intense light and weather, sea level-growing, shade-loving New Guinea impatiens were trialed in Fort Collins and genetically became a NEW sun-loving, high altitude, outrageously popular plant! That’s the value of CSU’s trial gardens.

CSU’s efforts, along with help from the Larimer County Master Gardeners, reward Colorado plant enthusiasts with complete findings on trial favorites. Find the last three years “Best Of” Annuals, “Top Performer” Perennials, and “Cool Season” winners here.

Watch for the announcement of the 2023 winners soon!

Mr. Kitty Cat joined me while I perused the Perennial Demo Garden. Photo: Lori Williams

Rinse and Repeat: Extend the Vegetable Season with Canny August Planting

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

Cultivating a vegetable garden this spring was certainly a challenge – we had late snow, followed by almost constant rain and, finally, some killer hailstorms. Seeds and seedlings were drowned or drifted into neighboring patches of soil and planting was delayed due to soggy soil conditions. Then cool temperatures and heavy rains required us to protect heat-lovers like tomatoes and peppers and stunted their growth. 

Late June hail decimated some Denver gardens. Photo: Molly Gaines

As I write this, we’re experiencing some typical July heat while forecasters are predicting a temperature dip that will lower temperatures to a more comfortable level. We can look forward to an abundant second harvest in September and October if we take advantage of better planting conditions this month.

WHEN AND WHAT SHOULD I PLANT?

Before answering the questions of when and what to plant, determine this year’s anticipated first frost date. Do this by counting backward from the number of days or weeks to maturity for each plant species. This will give you the date on which seeds must be planted. 

Find the first 2023 frost date for your city on the website of the Old Farmer’s Almanac. This resource estimates Denver’s first frost to occur on or about October 6^th , however this is only an approximation – keep up with local weather predictions as summer turns into fall. And remember that we can be flexible, thanks to plant protectors and moveable containers! 

Next, decide what to plant. The Denver Urban Gardens site features a guide to vegetable planting for commonly grown vegetables. It shows the recommended number of weeks (not days) to plant before the first frost. The column headed “fall planting” has the information to reference for the late gardening season. Note that we’re inside of or past the optimal seeding date for a number of these plants. Given this, consider using vegetable starts instead of seeds, and/or grow in containers that are easy to move or cover as the first frost approaches.

If seeing drop-dead dates for planting better suits your style, check out the ‘Colorado Vegetable Planting Calendar’ on the Asia Farming website.

Plant radishes now for a fall crop.

Before heading to the nursery –- and certainly before starting to plant –- take a look at Pueblo County Extension’s publication, “Late Summer and Fall Vegetable Garden Planting” for advice on plant selection and improving the tilth of soil that’s been used to grow the summer crop. 

If you like perennial herbs – decorative or culinary –- look for them in pots when you’re out and about looking for vegetable starts and seeds. Herbs like winter savory, lavender, and thyme will overwinter and, in some cases, remain green for cold-weather interest. Mulch well and water regularly until the soil freezes in late November to promote good root growth for a fast start in the spring. Perennial herbs in small containers  can be brought inside during the winter and returned outdoors to perk up the garden as soon as nighttime temperatures warm to a safe level in spring. This website lists some perennials that survive Zone 4 and 5 winters and popular annual herbs for fall planting.

It’s not quite time to plant garlic, but if it’s on your fall schedule, the sheer number of available cultivars and flavors requires researching possibilities and ordering bulbs NOW. Here’s a good article about growing this crop in Colorado, featuring some well-performing varieties. Local nurseries are or will soon be stocking garlic bulbs but consult some mail-order sources for the more exotic types. And for everything essential to know about growing garlic in our climate, check out the Master Gardeners’ September 2020 blog post “‘Growing Garlic in Colorado.”’

PLANNING FOR DISASTER

Inevitably an unexpected run of bad weather will occur in September or October: a hard freeze, rains that drown seeds and seedlings, even a heavy wet snow that brings the growing season to a screeching halt by snapping plant stems in two and withering tender foliage. We can minimize this damage by using a few effective tools:

• Row covers and frost blankets (sheets from the linen closet will work in a pinch)
• Anti-freeze bags (these come in many different sizes and are great for bushy plants)
• Cold frames (require advance construction but are handy year-round)
• Morning watering when frost is expected that night (hydrated plants are more resistant to frost damage)

Good luck with your late-season veggies! As always, please contact the Denver County Extension with your gardening questions. 

Colorado Gardening Calendar for August 2023

By: Gail Leidigh CSU Extension-Denver Master Gardener since 2021

August is a fabulous month for enjoying your garden. Much of the work from earlier in the season will have paid off at this point. Since August is often hot and dry, it’s important to make sure your garden is getting the right amount of water, and to remain observant for stressed plants. Mark your calendar to get these gardening to-do’s done in your yard and garden.

Also this month and through September 15^th, CSU Extension is accepting applications for the next Colorado Master Gardener class. To learn more about our program, explore the resources at www.ColoradoMasterGardener.org and read Let’s Grow Together: Becoming a Colorado Master Gardener by Felicia Brower.

The vegetable garden at the Denver County Extension office. Photo: Merrill Kingsbury

A Yard and Garden Checklist for August

Vegetable Garden

• As your veggies ripen, harvest them, and if you cannot eat them right away, check out these good ideas to preserve them for later from Master Gardener Lois Margolin.
• How are your tomatoes doing? Growing tomatoes in Colorado can be tricky, with our wide temperature ranges and winds that prevent pollination. Some ideas for helping with your tomato problems can be found in this video on the PlantTalk website.
• Extend your gardening time by planting cool season vegetables such as peas, broccoli, and kale.

Trees and Shrubs

• Pay attention to signs of stress and desiccation in woody plants, and supplement with water as needed.
• Prune back summer blooming shrubs that have finished flowering, and that will bloom next year on this season’s growth. (It’s too late to prune spring blooming shrubs such as forsythia and lilac.)
• Always avoid trimming trees when they are water stressed by hot and dry conditions – they need to conserve all the energy they can this time of year.

Lawn Care

• During periods of high temperatures, a lawn may need as much as 2.5 inches of water or more per week.
• Mid to late August is a good time to over-seed bare spots in the lawn.
• The best defense against weeds in the lawn is thick and healthy grass, and you can encourage this by cutting the grass high – about 2.5 inches or higher.

Photo: Gail Leidigh

Perennial Flower Beds

• Some plants will start going to seed this time of year. If you don’t want the plant to self-seed, seed heads can be cut back. Or leave the seeds for the birds to enjoy.
• Weed ‘em and reap: Continue weeding the yard and gardens now, and reap the rewards later.
• Take note of what worked this year and what did not. Many perennials will be on sale at the end of summer and this fall, and it is a great time to fill in bare spots or replace plants that didn’t make it.

Annual Flower Beds

• Check the soil moisture in pots and hanging baskets frequently, as they will dry out quickly in the summer heat and wind.
• Clear and thin out plants that are fading, and make room for fall annuals that love the heat such as angelonia, ornamental kale, and daisy rudbeckia.
• Dead-head to encourage growth of new blooms.

Enjoy your garden this month!

Colorado Gardening Calendar for July 2023

By: Valerie Podmore, CSU Extension-Denver Master Gardener since 2020

Roses in bloom for a “hot” minute, photo by Valerie Podmore

With all the precipitation we’ve had this year, our gardens have been busting out all over with beautiful blooms, vegetables are loving it and of course weeds are growing like gangbusters. I bet many of us have not really had to water much yet…how great is that?!

This month let’s get out there and keep on top of the bounty that this amazing weather has brought us, knowing that in Colorado the weather can turn on a dime, so we need to be prepared for anything.

Vegetable Garden

• This is the month when we can start harvesting our ripening vegetables, fruits, and herbs.
• Look to plant vegetables for fall harvest. This information sheet has great ideas!
• Since July is typically hot and dry, we may need to water but make sure not to water from above to prevent mildew and other maladies from forming.
• This article is a great overall guide on caring for veggie gardens. I’ve bookmarked it for my future reference as a beginner veg gardener!

Trees and Shrubs

• While we’ve had ample water this year, we still need to watch the weather and make sure our trees and shrubs are adequately watered when we’ve received no precipitation in 10-14 days to prevent disease. Denver Water has a nice, succinct guide to help.
• Emerald Ash Borer has been detected in a small area of Littleton and Carbondale (both new locations) and this information can help you plan ahead if you have ash trees.
• Our landscape shrubs are probably growing beautifully right now and seeing some dead branches might drive us crazy (us = me), so know that while this is probably not the prime month for pruning, removing these dead canes can help. This pruning guide contains so much great information I’ve had to read it over more than once.

Lawn Care

• Our lawns are probably quite happy with all the moisture we’ve received, and let’s keep them thriving with proper care.
• Fertilizing can help if done correctly at the right time.
• If you are considering converting your lawn to less water-intensive landscaping, this info sheet contains a multitude of conversion methods and ideas.

Bunny in my garden, relaxing and digesting the flower leaves it just ate, grrrr! photo by Valerie Podmore

Perennial/Annual Flower Beds

• Both perennials and annuals can benefit from deadheading to promote more flowering and preventing them going to seed (if that’s what you want).
• Pull those weeds to prevent them taking over your flower garden!
• This document has a plethora of information about annuals and perennials during low-water periods because let’s be honest, we WILL get back to a lower water situation soon enough.

Oh, just one more thing (a la Columbo!), don’t forget that the “wonderful” Japanese Beetle will begin to make its appearance this month to destroy our hard work, so take a look at this article to learn more on this pest and how to battle it.

As always visit the CSU Extension Yard and Garden website (https://extension.colostate.edu/topic-areas/yard-garden) for more gardening tips.

Colorado Gardening Calendar for March 2023

By Valerie Podmore, CSU Extension-Denver Master Gardener since 2020

These Tulips have restored my faith in spring and gardening! by Valerie Podmore

I have a confession to make. I have not been thinking about the garden much this past winter and almost thought (dare I say it) I might just pack the whole thing in. However, my eye was caught this morning by the sight of tulips starting to pop through the soil and it made me happy, and I think I have caught the bug again! So, let’s see what we can do now that we are starting to see more sunshine, and the days are getting longer. MARCH is one of the best months to prepare for the upcoming growing season, so mark your calendar to get these gardening to-do’s done in your yard and garden.

Vegetable Garden

This year I am determined to try raised bed gardening and am beginning to research what it takes to succeed. Maybe we can learn together!

• I’m starting with this article to help me figure out what to plant as a new veggie gardener.
• The raised bed method of gardening is explained in depth here. I must work to not get overwhelmed by the wealth of knowledge!
• If you are like me and have delusions of veggie growing grandeur, you will possibly have more seeds than any normal human should be allowed to have! Many of these are probably no longer viable, so best to inventory your seeds and order any you might still need.
• Last week’s post about seed starting is a timely and great way to educate ourselves on starting our plants using the DIY method.

Trees and Shrubs

• Since we’ve had so much snowfall (we’ve certainly needed the moisture!), supplemental watering is possibly not needed, but anything can happen in March so remember to water your trees and shrubs if there’s a drop-off in precipitation.
• This is a great month to prune trees and shrubs for those who want to get outdoors and “DO SOMETHING!”

Lawn Care

• If you love late winter/early spring lawn and garden care (who doesn’t love a good spring clean?) there are great suggestions in this article.
• Early March is a great time to sharpen up your mower blades and add or replace oil, clean shovels and pots, and generally tidy up anything that has been languishing in wait for warmer days.
• Late March is a great time to start aerating as long as the ground is not frozen.

Perennial/Annual Flower Beds

• While most of our garden isn’t completely awake yet, we can still take stock of what plants worked last year and what we’d like to fill in this year.
• That brings us to seeds and bulbs! See what bulbs you’ve got that can be replanted from storage; what seeds can be sprouted indoors.
• If you attended the Colorado Home and Garden Show last month (probably good that I didn’t, as I would become way too over-ambitious!), use any ideas you gained for changes you want to make.

Don’t forget to visit the CSU Extension Yard and Garden website (https://extension.colostate.edu/topic-areas/yard-garden) for more gardening tips, and yay spring!

Colorado Gardening Calendar for SEPTEMBER 2022

By: Valerie Podmore, CSU Extension-Denver Master Gardener since 2020

Summer’s not done yet! by Valerie Podmore

Let’s not get downhearted at the impending end of growing season! September is one of the best months for continuing harvests, enjoying our gardens, and yes, preparing for the end of summer (sad face). Mark your calendar to get these gardening to-do’s done in your yard and garden.

Vegetable Garden

• Continue consistent watering practices. We might be cooling down, but we are still dry, so don’t let your hard work “die on the vine!”
• Plant fall vegetables! Some do really well in cooler weather and ripen quickly for harvest, such as lettuce, kale, arugula, Swiss chard, and spinach which can be direct seeded.
• Save heirloom plant seeds if you are looking to start your own plants for next season.
• Get your plant covers at the ready just in case we have a (pretty typical) cold snap or just in case temperatures dip lower than your veggies enjoy.
• Make sure to clear away any dead vegetation to prevent disease or pest proliferation.

mmmmm….the fruits of our labors. Photo by Valerie Podmore

Trees and Shrubs

• Water, water, water! Just like our vegetable gardens, our trees and shrubs need to be consistently watered. Weekly is a good schedule, but this fact sheet provides very thorough advice.
• Trim only branches or limbs which are damaged or diseased at this time.
• Be careful with fertilizing trees and shrubs. This link has good information on fertilization if there’s been particularly dry weather (when is it not?).
• While planting in fall might not be the #1 time, it’s still possible to find discounted plants and if you finish before the end of October, your tree or shrub will have some time to establish itself before the cold of winter.

Lawn Care

• Aerate this month to allow oxygen to get to the roots of your grass. This is an awesome turfgrass post for more information.
• Water deeply, giving your grass a good, long drink. Weekly for even 45 minutes is more beneficial than more often for less time.
• This great fact sheet has probably everything you need to know for keeping your lawn healthy.
• While the scourge of Japanese Beetles might be behind us, this is a prime time to apply grub-killers like grubGONE! and GrubEx to turf to help prevent them returning.

Perennial Flower Beds

• Water (I know, it’s like déjà vu!) weekly until the ground freezes to give the roots a chance to develop before winter.
• Cut back spent plants but consider leaving some stems and seed pods in place for pollinators and birds. This post from our Routt County Extension friends posits a different way of thinking about cleaning up (or not!) the season’s leftovers.
• Look at what needs filling in or doesn’t work and make plan for spring.
• Purchase fall planted bulbs – who doesn’t love plant shopping? This is the time that plant stores, catalogs or online sellers are stocking up so go crazy!

I can’t wait to shop! Photo by Pixabay

Annual Flower Beds

• Clean up annuals in containers and sanitize any pots you’ve emptied.
• Get some fall color such as chrysanthemums or pansies which overwinter quite well if mulched properly.

Other Projects

• KEEP WEEDING! That is all.
• Start prepping houseplants that have been outside to come back inside for winter. Check out this post for details.
• Finally, this is the month when Colorado Master Gardener program applications will begin! These will be posted on our main website with applications open September 1 – October 16. Do you or someone you know want to apply? Please DO!

Visit the CSU Extension Yard and Garden website (https://extension.colostate.edu/topic-areas/yard-garden) for more gardening tips.

Colorado Gardening Calendar for June

By Valerie Podmore, CSU Extension-Denver Master Gardener since 2020

Butterfly on lavender. Photo from Pixabay

So, who had the fifth earliest 90-degree day and the eleventh latest spring snowstorm in May on their garden bingo cards last month? Well, it’s June and who knows what else Mother Nature will throw at us! 

Thank you to those who attended the CMG Plant Sale during the great snowstorm of May 2022. Likely, you’ve either have planted your new purchases or will be doing so soon! 

JUNE is one of the best months for being happy that we can go outside into our gardens and watch (or MAKE) them grow. Mark your calendar to get these gardening to-do’s done in your yard and garden.

Vegetable Garden

• If you’ve planted your cool season-veggies (peas, lettuce, kale, and spinach) last month, this is the time to harvest to prevent these going to seed.
• Warm-season plants like tomatoes, peppers, and eggplant will thank you for continuing to transplant them this month to keep your harvest going.
• Water evenly, close to the soil rather than overhead to prevent fungus and other plant diseases from forming.
• Don’t forget to continue to perform the most fun activity ever…WEEDING! You don’t want your lovely veggies having to compete with these evil garden monsters.
• Apply organic mulch to keep the moisture up and the weeds down. Untreated grass clippings (i.e., chemical-free) are a good option.
• Make sure to join the Grow and Give program which supplies fruits and veggies to folks in our local communities who might have a need for our extra bounties.

Trees and Shrubs

• If there has been no precipitation in a month, make sure to water your tree(s). Trust me even with the recent snow, we are still very dry.
• If you are thinking of doing more xeriscaping, take a look at this information sheet on trees, remembering that less water for the landscape means less for trees and shrubs as well if we don’t set up the landscape in a water-wise way.

Lawn Care

• As mentioned in last month’s calendar blog, Japanese beetle control at the grub stage by using products like GrubGONE! that contain bacillus thuringiensis var. galleriae (Btg) must be applied to turf in May and early June to take effect. Check with a local nursery regarding availability of these products or order them online. Consult this Extension fact sheet regarding Japanese beetles for advice on dealing with this pest throughout the summer.
• This information sheet gives great information on watering during a drought, which we are experiencing even with late moisture we received.
• This might be a good time to start looking at more xeric plants as mentioned above in the tree/shrub section. Colorado and the west are getting dryer and we could look at different ways to reduce our water use including cutting back on traditional, high water needs lawns. Watch for our upcoming blog post on this topic, too.

Perennial/Annual Flower Beds 

• Our perennials require good watering during the month, low-level, slow watering to prevent fungus and other plant diseases caused by over-head watering. This applies to annuals as well, whether in containers or beds, to prevent them from drying out.
• Dead heading (the practice of removing spent blooms) will keep new flowers blooming throughout the month.
• If you have iris plants that have been in place for 3-4 years, consider dividing them after they finish blooming to keep them growing strong…kind of like us cutting our hair!
• This article contains a trove of information on creating and maintaining a perennial flower bed.
• Low-water flowering plants information (for both perennials and annuals) can be found here. An awesome read!

In closing, as June is Colorado Pollinator Month, take a look at this post on how we can attract these very important animals to our gardens.  Also visit the CSU Extension Yard and Garden website for more gardening tips.