Avoid Landscape Failures

Garden Friend - I thought you might like to read my recent garden article that ran in The Denver Post about landscape failures.

Link to The Denver Post article, click HERE. The full article is below.

Colorado gardening tips: How to avoid landscape failures

These juniper trees were planted too close to the house and are much too large for the location. (Betty Cahill, Special to The Denver Post)

By Betty Cahill | Special to The Denver Post

April 30, 2024 

Landscape design and planting techniques are personal choices by homeowners, unless you are moving to a house that is already landscaped. Unfortunately, mistakes and missteps can happen when planting and during aftercare. And then, too much time passes, leaving the plants to grow and pose issues and dare I say become eyesores with eventual decline and possible plant death.

Avoid Volcano Mulch around trees which prevents air and water from reaching the roots. (Betty Cahill, Special to The Denver Post)

If improving your own planting plan is on your front burner this outdoor gardening season, then there are ways to change bad planting habits.

Plant placement

The most used landscape phrase by green industry professionals and gardeners in the know is “right plant, right place.” Saying it out loud does not make it so unless you take the meaning to heart (and mind). This means educating yourself about what the plant needs for light requirements, soil conditions, water requirements and, above all, size. (How tall will a tree eventually grow? How wide?)

The tag attached to a plant or tree is a wonderful tool and planting guide: study it, take a photo, file it. And guess what? Even though the tag says a plant matures to a certain height and width it won’t automatically stop growing when it reaches those dimensions.

Sure, the cute little shrub may look just perfect on planting day in front of your beautiful front door, but is it the right plant in the right place once it grows up and out?

Proper planting

Burlap should be removed as much as possible after the rootball is placed correctly in the planting hole. This tree was in the process of dying so was removed. (Betty Cahill, Special to The Denver Post)

Correct tree planting often determines its fate. Obvious signs of poor planting include seeing twine, wire baskets or burlap covering the root ball. If a tree is declining and eventually dies, there may be other causes besides improper planting. Under- and overwatering, soil conditions, pest infestation or poor location may be contributing factors. When a tree is eventually removed, it’s not difficult to see one or more of the causes of failure.

When trees are planted too deeply, they look like telephone posts from the ground up. There should be an obvious root flare visible when properly planted. Even if you hire out for planting, learn the correct method and monitor the actual planting. Trees can be pricey and a lifelong responsibility for care. Check with your local nurseries or the resources below for best planting practices.

Tree mulch should not be piled too high (often called volcano mulch), which doesn’t allow for proper air and water penetration. Also keep mulch directly away from the trunk so it’s not a place for insects to hide. Too much water close to the trunk may lead to rot.

Adding mulch for a finished look to landscape plantings and borders can be beautiful and healthy for cooling plant roots on hot days, while keeping weeds at bay. Mulch choices include shredded bark, chunk bark, bark chips and arborist chips. If you would rather use rock, there is pea gravel, river rock, cobble and stones.

Weeds still find borders and beds with landscape fabric, so avoid using it. (Betty Cahill, Special to The Denver Post)

Think twice about installing landscape fabric under mulch everywhere in a landscape. Weeds will return in a year or two and become more difficult to pull the longer they are left to grow in the fabric. Plus the soil underneath fabric becomes hard-packed and doesn’t allow plant roots to move deeper in the soil; they stay closer to the surface in desperate need and search for space, air and moisture.

Below are some common landscape oops and suggestions for mending. Both examples show plantings too close to the house and much too large for the location. Either live with it, replace it with smaller, more appropriate plantings or move it.

Tree planting don’ts

• Seeing a tree with so much visible twine is not only incorrect planting, but also sad. If a tree has dead branches and stressed needles, the only solution is to remove it and plant another tree nearby correctly.
• Burlap should be removed as much as possible after the rootball is placed correctly in the planting hole. Don’t place mulch too close to the trunk plant the root flare too deeply.
• Avoid volcano mulch around trees which prevents air and water from reaching the roots.
• Weeds still find borders and beds with landscape fabric, so avoid using it. A 2-3 inch mulch application helps keep weeds down and are much easier to pull. Plant roots will be much happier than being smothered by fabric.

Landscapes will never be perfect yet there’s always room for improvement. Enjoy the process and keep on keeping on.

Resources

Landscape Fabric: A Cautionary Tale gardenprofessors.com

Mulches for Home Grounds: extension.colostate.edu

Selecting, Planting and Caring for Trees csfs.colostate.edu

 

Betty Cahill is a freelance writer who speaks and writes about gardening in the Rocky Mountain Region. Visit her site at http://gardenpunchlist.blogspot.com/ for even more gardening tips.

 

 

 

Tips for Shrub and Perennial Pruning and Warm Up those Veggie Beds!

Garden Friend - I thought you might like to read my recent garden article that ran in The Denver Post about pruning for the new gardening season.

Link to The Denver Post article, click HERE. The full article is below.

Tips for perennials, shrubs and vegetables in the spring

Rose of Sharon blooms on new wood each year, so if the shape is a bit unruly or has gotten a bit too tall for the space or too close to a structure, by all means prune it now or by early May. (Timothy D. Wood, provided by Proven Winners)

By Betty Cahill | Special to The Denver Post

April 7, 2024

Spring in Colorado is grand if you’re OK with switching between a heavy jacket and a tank top. We never complain about spring rain or even snow since all moisture is welcome and needed for water use, landscapes and agriculture.

Here’s your April outdoor plant pruning and vegetable tips list for when the weather is cooperating.

Perennial cutback

The general guideline for perennial blooming plants is to cut back to the ground all the dead, brown stems and foliage that wasn’t cut in the fall. This is where new growth will soon emerge; some are already showing their green. This can be done when the ground dries out between now and before plants are really putting on new growth (April-May). To allow for new spring growth, get rid of all that dead foliage and any new weeds popping up. Toss it all in the compost pile or bin if the foliage is disease-free from last year’s growth.

The general guideline for perennial blooming plants is to cut back to the ground all the dead, brown stems and foliage that wasn’t cut in the fall. (Betty Cahill, Special to The Denver Post)

After cutting back, feel free to add some quality compost around perennials to give them a little nutrient bump for the season. Fertilizing blooming perennials is fine during the growing season; just don’t add too much or it may end up causing lots of foliage growth and fewer blooms. Excess fertilizer runoff is not good for our soils and waterways.

Wait a little longer to prune the woody types of perennial herbs like lavender and culinary sage. These plants don’t like being cut when they are still dormant, and it takes them a little time to push new growth in the spring that begins on the older, lower woody stems. Wait until you see tiny leaves on the culinary sage plants to cut off the clearly dead upper stems. This may be in late April or May. For lavender, that means cutting only a couple of inches down into new growth (obviously including any spent blooming wands from last year).

Popular spring and summer blooming shrubs

• Russian Sage (Perovskia artiplicifolia) is a favorite of many homeowners. However, if you’re looking for mid- to late-season bloom and low water use (once established), also consider these other great choices: blue mist spirea, catmint, leadplant, Mohave sage and lavender. Cut Russian sage to the ground in spring (leave a few inches up to a foot or so) to make room for another season of growth and bloom.
• Blue Mist Spirea (Caryopteris), which blooms in late summer, is often cut hard to the ground every year similar to Russian sage. This is OK, but it’s also appropriate to prune it every two to three years in spring. Cut down to where you see new, healthy leaves forming at the base of the stems. Basically, it means cutting off the spent top flower growth, totaling about half or a third of the entire plant.
• Butterfly Bush: Just like blue mist spirea, Buddleia davidii (butterfly bush) can be cut every couple of years each spring or every year. Cut down to about 12 inches above a set of new buds. For the spring-blooming butterfly bush (Buddleia alternafolia), wait and prune spent blooms to new growth right after blooming.
• Rose of Sharon (Hibiscus syriacus): There’s nothing quite so dramatic and head turning as seeing late summer blooms on Rose of Sharon. Yearly pruning isn’t entirely necessary. Rose of Sharon blooms on new wood each year, so if the shape is a bit unruly or has gotten a bit too tall for the space or too close to a structure, by all means prune it now or by early May.
• Hydrangea pruning may seem overwhelming. To simplify, examine the stems each spring and look for obvious swelling buds. If buds look like they will open soon, then these types should not be pruned now; wait until after they finish their bloom. They formed these buds last fall (old wood) for this year’s bloom cycle. Hydrangea shrubs that bloom on new wood will grow buds this spring, so they can be pruned in late winter to early spring. Pruning during the growing season may risk cutting off flower buds. There are five commonly grown hydrangeas in our area.

  

  A relatively new pink hydrangea called Invincibelle. This group blooms on new spring growth so a good thorough prune will bring rich rewards in summer blooms. (Ed Post, provided by Proven Winners)

   

  1. Hydrangea macrophylla (the very popular big leaf or mophead of pink, violet, blue and red flowers like Grateful Red and Endless Summer. This group is considered the classic hydrangea in looks and growth. The buds are set on the previous year’s growth, but some varieties also set secondary buds that flower later in the summer. Pruning now should be limited to removing dead wood, wait until right after flowering to tackle shaping or just leave alone if they are perfect for your viewing pleasure.2. Hydrangea arborescens is another popular group known as the Annabelle or smooth-leaf types. Bloom colors are mostly white or creamy white. There’s a relatively new pink called Invincibelle. This group blooms on new spring growth so a good thorough prune will bring rich rewards in summer blooms. Cut stems back about a third of total height.

3. Hydrangea paniculata are easy-to-grow hydrangeas with mostly lime green, white or white with pink-tinged blooms round to pointed in shape. They bloom on new wood, with flowering generally in the summer, and last several weeks. Cut back in early spring to right above a bud, leaving about two 2 from the ground. Cut out the thin, pencil-size wood which can’t hold up the large flowers. Limelight is a great choice for hedges and containers, and is available in tree form as well.

4. Another classic is the oakleaf hydrangea (Hydrangea quercifolia), which is native to the Southeast. It is deeply lobed with oak-like leaves and showy, white summer flowers. This group produces flowers on old wood like the macrophylla group, so simply prune any dead wood in the spring but wait and do pruning (if any) after it finishes putting on its show. These prefer some winter protection. Bonus with its red, orange to purple fall foliage!

Limelight hydrangea is a great choice for hedges and containers, and is available in tree form as well. (Chris Brown, provided by Proven Winners)

5. Hydrangea anomala petiolaris, or climbing hydrangeas, are beautiful when planted in areas with wind and late afternoon sun protection like a north- or east-facing location. Its aerial rootlets will easily cling but appreciate some support. With exfoliating cinnamon-brown bark and fragrant white flower clusters, what’s not to love? This vine can climb, so give it room. It blooms on old wood, so just prune out unwanted stray stems after blooming.

Vegetables

Get a jump on your early spring planting season by warming up in-ground and raised beds with 4- to 6-mil clear or black plastic. Anchor the plastic with boards, brick or soil. Leave it in place for a couple of weeks.

When soil temperatures are 40 degrees or warmer, it’s safe to plant hardy cool-season transplants including broccoli, cabbage or direct-seeded kohlrabi, peas, lettuce, onions and onion sets, radish, spinach, turnips and potatoes.

Welcome to the new outdoor home-grown gardening season.

By Betty Cahill | Special to The Denver Post

 

Betty Cahill is a freelance writer who speaks and writes about gardening in the Rocky Mountain Region. Visit her site at http://gardenpunchlist.blogspot.com/ for even more gardening tips.

 

New Perennials and Annuals for 2024

Garden Friend - I thought you might like to read my recent garden article that ran in The Denver Post about new plants for the 2024 gardening season.

Link to The Denver Post article, click HERE. The full article is below.

New must-have flowers and plants for the upcoming Colorado gardening season

Not just any petunia will do

The Elanos Rose Geranium, a lightly scented deep pink geranium with an upright spreading habit (14 by 14 inches) that deserves a place in mass plantings, borders, baskets and containers. (Deborah King, provided by Tagawa Gardens)

By Betty Cahill | Special to The Denver Post

PUBLISHED: April 3, 2024

Visits to the garden center to explore the new season’s plants might equal the excitement of arriving at a much-anticipated, never-been-to-vacation destination. Is it the newness of both activities that gets the heart thumping and ready for exploration?

Here are some of the newest, must-have perennial and annual plants for the coming outdoor gardening season. Note: This is a drop in the garden bucket when you see the plethora of plants waiting for you this spring.

Perennial plants

Joel Russell, the Colorado certified nursery professional and perennial manager and Buyer at Echter’s Nursery & Garden Center in Arvada, said “new plant introductions increase energy for the customer’s buying experience.” This year, Echter’s has 30 plants that are new to the market or new to Echter’s. Joel knows his customers and helps set them up for growing success by asking questions about where plants will be in the landscape, taking into consideration the plant’s sun and water requirements.

“Many customers want traditional hydrangeas and boxwoods, but the waterwise plants that need less water once established are very popular, and getting more so.”

Petunia Hybrida Itsy Magenta. Take container gardening to another blooming level with this small, bright magenta and superior growing petunia. (Deborah King, provided by Tagaway Gardens)

Russell’s top perennial picks for 2024:

• Scabiosa columbaria Giga Silver, common name Pincushion Flower. A new pincushion plant with more bloom power and size than the standard blue. Zone 5, full sun (very heat tolerant), well-drained soil, moderate watering. A touch of electric lavender outer petals with creamy white centers and dense silver foliage, 15-20 inches tall and 10-15 inches wide. Blooms spring through summer; deadhead to keep blooms coming. Deer resistant and drought tolerant once established. Works well for container gardening, borders, rock gardens, cutting. Loved by butterflies.
• Baptisia Grape Escape, common name False Indigo. Gardeners who know baptisia know they are not only low maintenance, but also long-lived from their deep tap roots. They look wonderful both in and out of bloom with their pea-like flowers and mounding, lush foliage. Grape Escape is a plant to behold, with deep magenta petals and creamy to yellow keels (lower petals) that bloom above the dense, green foliage from late spring to summer. Zone 4, full sun to part shade, average moisture (drought tolerant once established), poor soil tolerant, deer resistant, 42 to 48 inches tall and 32 to 40 inches wide. Plant as a specimen, back of the border, use for cutting, blooms look great in a vase. Choose location carefully; baptisia does not like to be moved. Attractive to many types of bees and pollinators.

Ross Shrigley, executive director of Plant Select, is the go-to horticulture professional for knowing plants that every garden should be growing. Plant Select is Colorado’s leading brand of plants that have been tested to thrive in challenging High Plains and intermountain growing conditions. Each year, it introduces plants that can easily be identified and found in many independent garden centers. Refer to the Plant Select website for hundreds of more plants in searchable categories to match your landscape. Design ideas are available, too, along with many other helpful resources.

This new Pincushion Flower works well for container gardening, borders, rock gardens and cutting — plus, butterflies love them. (Joel Russell, provided by Echters)

Shrigley’s top perennial pick for 2024:

• Teucrium Harlequin’s Silver, common name Eversilver creeping germander. To say that a groundcover has year-round appeal is big praise. Eversilver easily lives up to this status as a behaved, low-growing bright carpet of silver foliage. It blooms in early summer with pretty purple flowers and often reblooms in the fall. Take a piece of foliage and crush it for a delightful scent of what has been described as honey-pineapple. Deer and rabbits typically avoid it. Zone 5, full sun, drought tolerant once established and grows in well-drained, alkaline, rocky to sandy soils, 4 inches tall by 36 inches spread. Trim away any dead foliage each spring; otherwise no maintenance is required. Plant Everstilver in the toughest parts of the landscape — between streets and sidewalks (hellstrips), borders and rock gardens. Loved by pollinators.

Annual plants

Deborah King, annual supervisor/offsite project supervisor for Tagawa Gardens in Centennial, has one goal in mind with the scores of annual plants sold each new gardening season: “To provide a wide range for our customers as well as the very latest available in flowering plant material. Our annuals offer instant color with the changing seasons.” Deborah also sells the “best of” annual plants decided each year at the Colorado State University Annual Flower Trials. The trial program, like the Plant Select branded plants, are tried and evaluated for the top traits that gardeners want when purchasing annual plants: floriferousness, plant vigor, uniformity and ability to tolerate the tough growing conditions of the Rocky Mountain region.

King’s top annual picks for 2024:

• Best Petunia ’23 from CSU Trials, vegetative container: Petunia Hybrida Itsy Magenta. Take container gardening to another blooming level with this small, bright magenta and superior growing petunia. It blooms so well that the spent blooms are covered easily, so deadheading may be forgotten. Also does well in cooler temperatures and part shade. Plant in containers, window boxes, beds and baskets. Blooms spring, summer and fall until frost.
• Pelargonium Elanos Deep Pink, common name Elanos Rose Zonal Geranium. A lightly scented deep pink geranium with an upright spreading habit (14 by 14 inches) that deserves a place in mass plantings, borders, baskets and containers. Occasional trimming of faded flower heads is all that is needed; just stand back and watch it continuously bloom all season.

Resources

Plant Select: plantselect.org

CSU Annual Trials: flowertrials.colostate.edu

 

 

By Betty Cahill | Special to The Denver Post

Betty Cahill speaks and writes about gardening in the Rocky Mountain Region. Visit her site at http://gardenpunchlist.blogspot.com/ for even more gardening tips.

Get Your Tools in Shape for the New Gardening Season

Garden Friend - I thought you might like to read my recent garden article that ran in The Denver Post about getting your tools ready for the new gardening season.

Link to The Denver Post article, click HERE. The full article is below.

How to gets your tools prepped for spring planting  

Just like washing our hands to remove germs and bacteria, we need to do the same for our garden tools. (Betty Cahill, Special to The Denver Post)

By Betty Cahill | Special to The Denver Post

PUBLISHED: March 15, 2024

“If the only tool you have is a hammer, it’s hard to eat spaghetti,” says David Allen, a productivity consultant and writer. Could this analogy apply to using the right garden tool to effectively complete outdoor tasks?

No doubt, and taking it further: It is time to get tools in their best working condition for the new season.

Take a good hard look at your garden tool kit and then make some decisions. Are your bypass pruners making sharp cuts or are they doing harm by crushing the branch? If your trowel handle bends like a paper drinking straw when digging, then a new, hardworking one will change your garden life for the better. Maybe your tools just need a bit of spit and polish and a good sharpening session. And after your decisions are made, how about spaghetti for dinner?

The list of gardening tools to clean each season includes shovels, rakes, pitchforks, plant trellises, cages, stakes, accessories and containers. (Betty Cahill, Special to The Denver Post)

Clean and disinfect

Improve tool performance with a good cleaning. Just like washing our hands to remove germs and bacteria, we need to do the same for our garden tools. No need to spread any harmful pathogens from last year to established plants in the garden and new ones that will be planted soon. And when referring to tools, the list includes plant trellises, cages, stakes, accessories and containers (they’ll need cleaning and disinfecting, too). Some trellises and containers may not be easy to clean because of location and size, so do the best you can. Generally, wooden containers naturally repel fungi and bacteria. Where possible, wash with soap and water, rinse well and let dry.

Clean each tool well before disinfecting. Begin by giving each a strong blast of water to remove caked-on dirt and debris. Pruners can easily be dissembled by removing the nut or screws that hold the blades together, then the spring coil will slip off. (Keep track of the pieces.) Soaking in warm, liquid dish soap is all you need; use a stiff brush for hard-to-reach places. If there’s dried-on residue or sap, soak longer in soapy water or try a commercial product like Scrubbing Bubbles, which also disinfects. Read and follow label cautions associated with commercial products. Rinse well with water after cleaning and dry.

Lysol — or similar, store-brand versions — works well as a disinfectant for possible fungi, bacteria and viruses on tools. Simply place the tool in a bucket or box and spray all sides, or opt for the easy-to-use wipes. When finished, let the tools air dry.

Avoid using bleach products to disinfect pruners and other sharp-edged cutting tools. Bleach is very corrosive and can make pits in some metal tools. However, diluted bleach (one part bleach, nine parts water) can be used on rakes, shovels, spades, trellises, tomato cages and containers.

Undiluted 70% or higher concentration rubbing alcohol works well on small hand tools and pruners, although when used on tools to prune out fire blight, it might not be as effective.

All clean: Soaking garden tools in warm, liquid dish soap is typically all you need; use a stiff brush for hard-to-reach places. (Betty Cahill, Special to The Denver Post)

Rust can be removed a couple of ways: Soak exceptionally rusty tools in a jar or can of white vinegar for several hours or overnight. For shovels, soak a large rag with vinegar, wrap it around the shovel blade, cover with plastic and let it sit overnight. Use a wire brush after soaking to remove any residual rust. After soaking any tool, wash with soapy water, rinse and dry.

Also try using some elbow grease with sandpaper or steel wool for rust.

Sharpening

Want superior experiences preparing a meal and maintaining a garden? Assuming your answer is yes, both disciplines require sharp tools.

The easiest way to sharpen is to take your clean and sanitized tools to a reputable garden center, hardware store, small business or friend who specializes in sharpening gardening tools. Prices should be reasonable.

For DIY, a carbide file is great for smaller tools like pruners, loppers and small snipper shears. A mill file works well on shovel blades.

Once all your tools are cleaned, disinfected, and sharpened, give them a wipe down with some vegetable oil, which will help prevent rust through the season. Bypass pruners will benefit from a drop or two of hardware lubricant (like 3-In-One oil).

Tool tips

• During the outdoor gardening season, some smart gardeners brightly paint the handle of their trowels, making them easier to spot in the garden.
• A pocketed apron is handy for holding and carrying tools around while gardening. Plastic tubs decked out with a saddle bag to hold all sorts of tools (and perhaps an adult beverage for later in the day) are also popular.
• Take advantage of these warm late winter days into spring and do the work outside while soaking up some healthy vitamin D. Clean tools, sharpened pruners? Life is good.

Resources

How to Clean and Sharpen Tools

Laura, The Garden Answer

Video Betty and Alan Rollinger

 

 

Betty Cahill is a freelance writer who speaks and writes about gardening in the Rocky Mountain Region. Visit her site at http://gardenpunchlist.blogspot.com/ for even more gardening tips.

Seeding - What and When 2024

Garden Friend - I thought you might like to read my recent garden article that ran in The Denver Post about seeding vegetables, herbs and ornamental annuals inside and outdoors.

Link to The Denver Post article, click HERE. The full article is below.

The countdown to growing season is on. Here’s how to start seeding indoors

The timing, seeding and planting information on seed packets can vary per company. (Betty Cahill, Special to The Denver Post)

By Betty Cahill | Special to The Denver Post

PUBLISHED: February 27, 2024

With the first couple of months of the new year behind us, gardeners are focused on one thing: the countdown to the outdoor growing season.

Vegetable seeds that need to be started indoors very soon for transplanting outside in March to April include broccoli, Brussels sprouts, cabbage, parsnips, onions and cauliflower. (Betty Cahill, Special to The Denver Post)

Because spring weather in Colorado can be all over the map with moisture and temperatures, we know that dates don’t necessarily equate to the exact time or window to start planting outdoors. However, there are some flexible rules to follow so that we won’t be left behind.

For newbies (and as a review for more experienced gardeners), there are three defined and overlapping outdoor growing seasons to put plants and seeds (based on type) in the ground along the Front Range. For higher elevations, adjust the spring and fall seasons by waiting longer in the spring and plan for a shorter fall growing season.

The indoor seeding season is based on timing, plant type, and what the seed packet says about the time needed to grow indoors under lights or near a sunny window before planting them outside.

In a nutshell: learn it (plant type you wish to grow); live it (plant in the correct window); love it (eat the fruits and vegetables and enjoy every bloom that you plant).

Planting windows overview  

The cool-season planting window ranges anywhere from March to the middle of May. These include cool-season vegetables, which prefer growing in cooler daytime temperatures and are tolerant of cooler nighttime temperatures. (Betty Cahill, Special to The Denver Post)

This planting and seeding overview shows the big picture of the cool and warm-season seeding indoor, outdoor and planting for all three planting windows.

1. The cool-season planting window ranges anywhere from March to the middle of May. These include cool-season vegetables, which prefer growing in cooler daytime temperatures and are tolerant of cooler nighttime temperatures. They include spinach, lettuce, peas, potatoes and beets, and cool-season annuals like pansy, calendula, snap dragon and sweet pea.

If snow is on the ground or it’s raining or snowing from mid-March to mid-May, the cool- season planting window may either be delayed or skipped; it’s your choice. The good news is you can plant most cool-season plants in mid-summer (season 3) for fall eating.

Tunnels, cold frames, row covers and cloches are recommended to help you through uncooperative weather.

2. The warm-season window is anywhere from mid-May to the middle of July. This group of plants must have warmer daytime and nighttime temperatures to grow and mature. They are intolerant of frost and temperatures in the 30s and do not grow well in the 40s. These include ornamental perennials, vegetables such as tomatoes, peppers, squash, corn and basil (herb), plus annuals such as petunias, geraniums, marigolds, sunflowers and cosmos.

3. Mid-summer (mid-July to August), also called the fall planting season, is when the third season planting window begins. This includes mostly cool-season vegetables that mature in sixty days or less and warm-season crops that also have a shorter maturity date like summer squash, okra and basil.

This is also a great time to plant perennials that were missed earlier. The selection may be more sparse, but many perennials begin going on sale later in the summer into fall.

Indoor seeding charts

For seeding plants indoors, the windows and tips can be found on one of the four charts linked here. They include indoor seeding for ornamental annuals, perennial and annual herbs, and cool and warm-season vegetables. Not included is a perennial indoor seeding chart, although many perennial plants can be seeded indoors while others are only available as grown plants in garden centers and online.

The timing, seeding and planting information on seed packets can vary per company. Some mention soil temperatures or map zones as guides to direct seeding outdoors, or a certain number of days from frost dates, to start seeds indoors. Pay attention and familiarize yourself with the seed packet information. The charts here try to accommodate most seed company brands.

Seed packets will give you instructions on how and when to plant, like these leek seeds. (Betty Cahill, Special to The Denver Post)

Vegetable seeds that need to be started indoors very soon for transplanting outside in March to April include broccoli, Brussels sprouts, cabbage, parsnips, onions and cauliflower.

Tunnels or cold frames are recommended for early planting when freezes and frosts are the norm. Soil conditions for setting out new plants or direct seeding need to be spot on, too — not too wet, frozen or cold.

Warm-season seeds including tomatoes and peppers are generally started indoors in late March to April for mid- to late-May transplanting.

Keep in mind that if you miss the window to start your seeds indoors, you can always purchase cool-season transplants at garden centers in February and well into spring. Circle back later in April and May to purchase warm-season transplants.

Trees, shrubs, lawns

Most shrubs and trees can be planted as early as March and all the way to early fall. The exception for woody plants and perennials is to try to avoid planting when temperatures are extremely warm — unless it’s a scheduled installation or a must for your landscape. It can be done, but pay close attention to watering and providing some shade for several days after being planted if possible.

Turf grass can be seeded or sodded beginning in spring. Seed cool-season grasses including bluegrass, fescue and ryegrass anytime from March through September. Seed warm-season grasses like blue grama, buffalo grass and Bermuda grass from April through July. Avoid seeding after early August so the seed has plenty of time to get established.

People living at 7,000 feet elevation or higher should seed or sod cool-season grasses when the temperatures remain warmed up in the spring and before fall frost sets in. Warm-season grasses at high elevations can be seeded in late June to early July if typical monsoon rains are present over a period of time to help the seeds get going. Or seed in late fall so that the seeds will germinate the following spring.

Resources

Building Inexpensive Hoop Houses Video with Betty Cahill:  Part 1  and  Part II

Frost dates and climate summaries for Colorado: cmg.extension.colostate.edu/gardening-resources/online-garden-publications/frost-frost-dates-and-climate-summaries/

High-altitude native grasses 

 

 

Betty Cahill is a freelance writer who speaks and writes about gardening in the Rocky Mountain Region. Visit her site at http://gardenpunchlist.blogspot.com/ for even more gardening tips.