Colorado Gardening Calendar for September 2023

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

Winecups reaching for water. Photo by Valerie Podmore

When I went on my (mostly) daily morning walk (I’m writing this in the 3^rd week of August by the way), the temperature was a lovely mid 70’s and my walking buddy said, “this is a really nice morning, almost like fall.” As we’ve had so many hot, hot July and August days, the thought of experiencing cooler ones is quite appealing! I’m sure our plants will enjoy that as well (not the walking part of course haha). Let’s look at our gardening to-dos for this month.

Vegetable Garden

Ok I admit, my first attempts at veggie gardening are not going great, mostly because I’ve not watered properly, I think. It could also be the location has much more shade than initially imagined. Remember that right plant, right place mantra? I didn’t! In any case, here are some tasks to perform this month for those of you who actually have real vegetables growing.

• Continue to harvest any ripe summer vegetables and clear out fallen leaves, weeds and other disease-causing debris.
• Plant cool weather vegetables now as they mature quickly and love less heat. These include lettuce, kale, arugula, Swiss chard, and spinach. Here’s a timely post on how to extend our growing season.
• Don’t forget to continue watering because we all know that Colorado can throw crazy weather at us…and it follows then to prepare for cold weather snaps too. There’s nothing worse than working so hard to grow something only to have it destroyed by Mother Nature. 

Trees and Shrubs

• Oh that watering thing again. It’s like some sort of Tamagotchi game (showing my age!) to make us desperately try to keep our plants alive! Keep an eye on the weather and water deeply when precipitation has been scarce. This information sheet has EVERYTHING you want to know about water.
• While we can prune, if necessary, try to avoid it during this month. Make note of branches that need attention and save the tasks for late winter or early spring.
• We may not realize it, but September’s cooler temperatures make it a good time to plant trees and shrubs as it gives enough time for the plant to acclimate in the warmer soil and prepare for the winter months. Here’s a great article on this very idea.

Lawn Care 

• This is a great month to revive our lawns by aerating and fertilizing or overseeding bare spots.
• As mentioned above, watering is still important to keep our lawns healthy so let’s continue caring for our lawns as fall is not the time to stop the good lawn care practices we’ve undertaken throughout the year.
• Tired of dealing with lawn? Now’s the time to start to plan a turf conversion. This page offers practical tips.

‘Autumn Joy’ sedum’s dusty pink blooms pop in September and last till frost. Photo by Linda McDonnell

Perennial Flower Beds 

• This is a perfect time to start cleaning up our plants as they begin to go dormant, by clearing away dead and mushy leaves, fruits or weeds which can cause disease.
• This quick read has good advice on clearing up the garden in the fall and pollinator-friendly clean up tips can be found here.
• Divide early blooming perennials such as iris, lily, hostas, bleeding hearts, and other bulb or tuberous species to keep them from crowding each other too much.
• For anyone who has a spare hour and some, and REALLY wants to nerd out on fall plant advice, take a look at this awesome video!

Annual Flower Beds

Because I’m lazy, I prefer perennial plants but of course we can’t minimize the impact that annuals have in the garden. The colors and variety are just so great!

• Make note of those annuals that you will want to replace next year.
• Get your pots of Chrysanthemums or pansies busted out to provide fall color, as these plants prefer cooler weather and add that color we sometimes need to combat that seasonal affective disorder that we have (well I’m speaking for myself here!).

As always, visit the CSU Extension Yard and Garden website for more gardening tips.

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.

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.

Celebrating Pollinator Week with Kids

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.

This Year’s Denver Extension Plant Sale Will Knock Your Socks Off

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

Denver Master Gardeners are again offering our friends and neighbors some matchless plant choices to kick off the growing season; be sure to save the date! We’ll be there regardless of the weather with not only great plants but also science-based gardening advice, so come on down! 

We’ll have a wide selection of vegetables and herbs grown by Denver Master Gardeners, along with an assortment of annuals and perennials.

All tomatoes, peppers, and other vegetables are $6.00. Annuals and perennials are priced as marked. Proceeds from the sale fund Denver Extension’s outreach efforts.

The vegetable and herb varieties offered are fabulous indeed:

Sweet Peppers
Ace Bell, California Wonder-Bell, Goddess Sweet Banana, Italian Marconi Red, Jimmy Nardello, Lesya, Nadapeño

Hot Peppers
Conquistador, Española Improved, Heritage Big Jim, Iberian Cayenne, Jalapeño Gigante, Jalmundo Jalapeño, Joe E. Parker, Las Cruces Cavenne, Lemon Spice Jalapeno, Mariachi , New Mex. Heritage Big Jim, NuMex Heritage 6-4 Chile, NuMex Joe. E. Parker , Passilla Bajio , Piñata Jalapeño, Poblano (Ancho), Primavera Jalapeño, Red Carribean, Sandia Select, Serrano, Shishito, Suave Orange, Vaquero

Heirloom Tomatoes
Abu Rawan, Amana Orange, Amish Paste, Arkansas Traveler, Black From Tula, Black Krim, Black Prince, Blondkopfchen, Brandywine Red, Burbank Slicing, Costoluto Genevese, Cour Di Bue, Dr. Wyche’s Yellow, Genuwine, German Pink, Gold Medal, Golden King of Siberia, Green Zebra, Heatmaster, Long Keeper, Martino’s Roma, Marvel Stripe, Marzinera, Minibel (Patio cherry), Mortgage Lifter, Orange Woodle, Principe Bourghese (Paste), Prize of the Trial (Cherry), Purple Calabash, Purple Cherokee, Red Fig (Lg. Cherry), San Marzano (Paste), Silver Fir Tree (Patio), Solar Flare, Stupice, Yellow Pear

Hybrid tomatoes
Ace Bush, Baby Boomer (Patio), Big Brandy, BushSteak (Patio), Celebritv, Cherry Sungold, Early Girl, Mountain Magic (Lg. Cherry), Red Beefsteak

Basil
Dark Purple Opal, Genovese, Italian Large Leaf, Sweet Italian, Thai Sweet Basil

Broccoli
DiCicco Heirloom, Belstar

Cabbage
Copenhagen, Michihili, Red Acre

Cantaloupe
Minnesota Midget Heirloom, Sarah’s Choice

Cauliflower
Purple of Sicily, Rober

Chard
Fordhook Giant, Ruby Red

Cucumber
Boston Pickling, Persian Gerkin, Marketmore, Space Master, Straight Eight, Arkansas Little Leaf

Dill
Fern Leaf

Eggplant
Black Beauty, Diamond, Fairy Tale, Gretel, Orient Express, Pumpkin on a Stick

Kale
Red Russian, Redbor

Lettuce
Cos-sunland (Romaine), Coastal Star (Romaine)

Milkweed
Showy

Oregano
Vulgar

Parsley
Giant of Italy, Moss Curled

Pumpkin
Cinnamon Girl (Pie), Duchess, Early Giant (Carving), Jill Be Little (Small decorating), Phat Jack, Rouge Vif D’Etampes (Cinderella)

Squash
Cube of Butter Summer, Delicata-Winter, Dunja-Summer, Honey Bear-Acorn Winter, Metro- Butternut Winter, Sunburst-Patty Pan Summer, Sunshine-Kobacha Winter

Tarragon
Mexican

Thyme
English Heirloom

Tomatillo
Grande Rio Verde (Heirloom), Purple Coban (Heirloom), Tomatillo Verde (Heirloom)

Watermelon
Blacktail Mountain, Golden Midget, Sugar Baby Heirloom

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We hope you’ll stop by for your favorite plants and try some new varieties too.

As always, please contact the Denver County Extension with your gardening questions. 

Low-Water Vegetable Gardening in Colorado

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

Water and vegetables go hand-in-hand. The more water you give to your growing vegetables, the bigger and better tasting the harvests tend to be. As water restrictions become common and conserving water becomes more important than ever, it’s going to be crucial for gardeners in Colorado to figure out how to resourcefully use water if they want to keep growing fresh vegetables.

There are a few key ways to cut back on water in the garden. Simple things like choosing vegetables that can survive (and even thrive) using less water, maximizing the water that you do use, and preventing water loss are all ways to keep your garden looking great without relying on excess water.

Chives are always the first thing to pop up in spring without any supplemental water. Photo by Felicia Brower

When it comes to choosing what to grow in your garden, it’s important to remember that different vegetables require different amounts of water. Vine crops need less water (and actually tend to be overwatered in the home garden), while beans and sweet corn typically need more water than other types of vegetables. Many perennial herbs don’t require a lot (if any) supplemental watering to do well. My parsley, chives, sage, thyme, and lemon balm are the first things to show up every year in my garden without any extra water to help them grow.

Not only do vegetables have different water needs, but some also need more water during certain parts of their life cycles. For example, peas need more water during their pod filling period while tomatoes need more water during flowering and fruiting. 

It’s also important to choose regionally-adapted vegetables. Vegetables that are selectively bred to excel in areas where drought is common are more likely to have fewer issues when they’re watered less in the home landscape. Search online for Colorado seed companies and choose vegetable varieties that are drought tolerant. While beans can often be huge water users in the garden, varieties like Zuni Gold, Paiute Gold tepary, and Sonoran White tepary are drought-tolerant and grow well without needing huge amounts of water. In fact, during some of my drier years, they stayed greener and kept producing while their neighbors wilted and struggled. 

Zuni Gold beans, a southwest Pueblo variety, are highly adaptable and drought tolerant, making them a favorite in my home garden.
Photo by Felicia Brower.

One of the best ways to conserve water is to maximize water efficiency. If possible, install in-ground drip irrigation or use cost-effective soaker hoses so that your water reaches the roots of the plants instead of being wasted on foliage or in spots without anything growing. Water at soil level near the roots in the morning, avoiding the heat of the day, to reduce the amount of water lost to evaporation and to avoid issues like powdery mildew on the leaves of your plants. 

Here are a few additional ways to grow a low-water vegetable garden: 

• Different soil types have different water needs, so water according to your specific soil type. Loamy soil needs deep, infrequent watering instead of regular, light daily watering while sandy soils need more frequent, less deep watering because they lose water faster than clay soils. 
• If you use overhead watering, don’t water your plants on very windy days. The wind will blow your water away and prevent it from reaching the roots. 
• Before you do any watering, test your soil’s moisture level. The surface of the soil might be dry but the roots might not be.
• Your garden layout can also impact how much and often you have to water your garden. Narrow rows need more water, so grow your veggies in beds, grids, or wide rows. 
• As with any plants in your home landscape, plant vegetables with similar water needs together. If you have a mix of drought tolerant plants and high-water plants, make sure they’re kept separate so you don’t overwater or underwater, both of which cause stress and can impact the quality of your harvest.
• Use mulch (green or otherwise) to keep moisture in the soil. You won’t have to water as much if you grow intensely (close together) or use another organic mulch to slow down evaporation. 
• Grow during Colorado’s shoulder seasons to take advantage of moisture from snow and spring rains and cooler temperatures, so there’s less water loss due to heat.
• Before you plant anything, take time to amend and prep your soil. Healthy soil retains water and is full of nutrients that prevent you from overwatering to try and make your plants stronger. 

As water conservation becomes more important in the west, it’s crucial to find ways to use less, especially for things like growing food. Follow CSU’s Colorado Vegetable Guide and the “Water Conservation in the Vegetable Garden” GardenNotes chapter for advice on best low-water vegetable gardening practices. 

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!