Category Archives: Uncategorized

Shedding Light on Houseplants

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Daylight saving time is on hiatus, the gardening season has drawn to a close and  the long shadows of winter will soon be here.  It seems like a good time to turn our attention to the light needs of indoor plants.

Most indoor plants hail from the tropics, making their ideal growing conditions far different from what we offer in our typical homes. Thin new leaves, loss of lots of older foliage and limbs stretching towards a window can all be signs that your plant is craving more light. Without adequate light plants are unable to store energy for growth.

Indoor light is more subtle than the light in our gardens, which can make it trickier to assess. For more precision, a photographer’s light meter or a simple light meter app on your phone will measure the light in foot-candles or LUX units. Horticulturists use foot-candles, so if you have a device which gives a LUX reading, search the web for an easy LUX to foot-candle calculator.

In general, growers characterize plants as needing high, medium or low light.  Here are some guidelines to help assess the type of light in your environment with greater accuracy.

High Intensity Light

  • 1,000+ foot-candles
  • 4-6 hours of sun per day
  • Crisp shadows and dark contrast at the brightest time of day
  • Within 2’ of east facing windows
  • Within 2’ of south-facing windows (October-March)

Medium Intensity Light

  • 500+-1,000 foot-candles
  • Within 2’ of north facing windows (April-September)
  • 2-6’ from an east or west-facing window
  • 1’ to the side of an east or west-facing window
  • Approximately 10-14 hours per day of fluorescent office light

Low Intensity Light

  • 50-500 foot-candles
  • Faint shadows at the brightest time of day
  • Within 2’ of north facing windows (October-March)
  • 6-10’ from south-facing windows (April – September)
  • Few plants survive in fewer than 50 candles

Knowing the light intensity will help determine the best placement of  plants and select  plants which will thrive. Variables such as humidity, drafts and temperature also factor into a plant’s health, so be sure to take this into consideration, too.  As always, knowledge and keen observation skills are key to successful plant care.

Additional information on plants and light:

Plantalk 1352: Interior Plants and Light

Plantalk 1314: Houseplants: Artificial Light

Starting Seeds Indoors

Christmas Cactus Care (effects of light on bloom)

 

Written by Linda McDonnell, a Denver County Master Gardener

 

 

 

 

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What’s In The Cauldron? The Meanings Of Plant Names

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“Fillet of a fenny snake,
In the cauldron boil and bake;
Eye of newt and toe of frog,
Wool of bat and tongue of dog,
Adder’s fork and blind-worm’s sting,
Lizard’s leg and howlet’s wing,
For a charm of powerful trouble,
Like a hell-broth boil and bubble.”

Doesn’t that just send a shiver down your spine? The immortal words of Macbeth’s witches tend to hang in the air, and you can almost hear the cauldron bubbling.
But what is that stuff in the cauldron?

Guess what? Most of it is plants!

Anyone who has worked in the garden has noticed that many plant names have odd, fanciful or gruesome names. If you really consider them, names like ‘dandelion’, ‘foxglove’ and ‘mistletoe’ are pretty odd, aren’t they?
The reason is multi-faceted. A large contributing factor is a socio-historical phenomenon known as ‘linguistic drift’, which is the term for the fact that words are changed over time. Originally, according to Oswald Cockayne’s ‘Leechdoms, Wortcunning, and Starcraft of Early England: The History of Science Before the Norman Conquest’, Dandelion was originally ‘Dent De Leon’, or ‘Lion’s Teeth’, referring to the dentition of the leaves.  Andrew Yang notes another good example in his work ‘Plant Names in Old and Middle English: Problems and Trends in Taxonomy’ : “The tan of mistletan, notes Sauer, “originally meant ‘twig,’ but it was later associated with tan [as OE] toe,” to form mistletoe.”

Another main contributing reason is pragmatic: it’s hard to forget a plant called ‘dead man’s fingers’ or ‘bear’s breeches’ as a rule, which made remembering and passing on plant knowledge much easier.

The Tryskelion Press gives us a short guide to the 16th century English plant name meanings in their August 2015 issue.

Old Name for Part Actual Part of the Herb Used
Eye Inner part of a blossom
Paw, Foot, Leg, Wing, or Toe Leaf
Guts Roots and stalk
Privates Seed
Hair Dried, stringy herbs
Tail Stem
Head Flower
Tongue Petal
Heart A bud or seed

Here’s a few examples of the common names in the 16th century and the same plants today.

Old Herbal Name Herb/Plant Name
Adder’s Fork Adder’s tongue
Adders Tongue Dogstooth Violet
Ass’s Foot or Bull’s Foot Coltsfoot
Bat Flower Tacca
Bat’s Wings Holly
Bat’s Wool Moss
Bear’s Foot Lady’s Mantle
Beggar’s Buttons Burdock
Beggar’s Tick Dianthus
Bird’s Eye Germander Speedwell
Bird’s Foot Fenugreek
Black Maidenhair Black Spleenwort
Black Sampson Echinacea
Black Snake Root Black Cohosh
Blind Eyes Poppy
Click Goosegrass
Clot Great Mullein
Corpse Candles Mullein
Corpse Plant Indian Pipe
Courtesy Summer Wind
Crocodile Dung Black Earth
Crow Corn Ague Root
Crow Foot Wild Geranium
Crowdy Kit Figwort
Crown for a King Wormwood
Cuckoo’s Bread Common Plantain
Dead Man’s Ashes Mandrake root
Death Angel Agaric
Death Flower Yarrow
Devil’s Apple Datura
Devils Dung Asafoetida
Devil’s Eye Henbane, Periwinkle
Devil’s Flower Bachelor’s Buttons
Devil’s Guts Dodder
Devil’s Milk Celandine
Devil’s Nettle Yarrow
Devil’s Oatmeal Parsley

So what was in that cauldron? Black mustard, Crowfoot, Holly, Horehound, Wormwood, and a lot of other rather powerful plants. I wouldn’t drink a cupful myself, but if you want to see visions and fly this brew would definitely do it.
Happy Halloween!

Sources

The Shakespere Standard, http://theshakespearestandard.com

Cockayne, Oswald.  Leechdoms, Wortcunning, and Starcraft of Early England: The History of Science Before the Norman Conquest, vols. 1-3.  Bristol, England: Thoemmes Press.  1864-66.

Gledhill, D.  The Names of Plants, 2nd ed.  Cambridge: 1989.

Andrew K. Yang, Plant Names in Old and Middle English: Problems and Trends in Taxonomy 

The Old English Herbarium (OEH) and Medicina de Quadrupedibus.  Hubert Jan de Vriend, ed.  Toronto: Oxford.  1984.

Tryskelion Press, Old World Names For Herbs And Plants, http://www.tryskelion.com/herbs_old_world_names_for_herbs.html

 

2018 Colorado Master Gardener/Colorado Gardener Applications Now Being Accepted

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We are now taking applications for the 2018 Colorado Master Gardener volunteer class. We are also recruiting Colorado Gardener Certificate students who take the classes without volunteering. The application deadline is October 18th, 2017 and weekly Wednesday classes run from January 24 through April 10, 2018 from 9:00am-4:00pm. Classes will be held at Denver Botanic Gardens and Jefferson County Fairgrounds. For more information about the program, please visit our website: http://www.cmg.colostate.edu/about.shtml

If you are interested, please call 720-913-5272 or email merrill.kingsbury@denvergov.org for an application.

If you live outside of Denver, please see this link for the CO Master Gardener Program in your county: http://www.cmg.colostate.edu/ask-cmg.shtml

Gardens in the Sky

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Denver Private Residence. Courtesy of Denver Green Roof Initiative

Green roofs or living roofs have been around for thousands of years. The Hanging Gardens of Babylon were constructed around 500 B.C. using tar and layers of reeds to waterproof structures, upon which lush plants thrived. Europeans have long embraced green roof design and today, about 10% of homes in Germany have living roofs. North America has been slower to adopt green roof design, but the practice is gaining momentum, particularly in urban areas including Chicago, New York, Portland and Washington DC. This November, Denver residents will vote on The Denver Green Roof Initiative, modeled after legislation in Vancouver, which requires commercial buildings in excess of 25,000 square feet to dedicate a portion of roof space to vegetation or solar panels.

Image courtesy of wikispaces.com

What are green roofs and why are they valuable? A green or living roof is one that is either partially or completely covered in vegetation on top of the human-made roofing structure.  There are two major types of designs – extensive and intensive. Extensive green roof systems include a thin waterproof membrane covered in a lightweight, shallow planting medium and low maintenance plants, often using a system of trays  Intensive green roofs involve a more complex system of layers, are more expensive, require greater structural support and allow for a wider range of vegetation, such as trees and shrubs (see diagram). Intensive green roofs can serve as parks or public spaces, such as the Mordecai Children’s Garden at the Denver Botanic Gardens or Highline Park, built upon an elevated historic freight line in New York City.

Anschutz Wellness Center -University of Colorado, Aurora. Courtesy of Denver Green Roof Initiative

Denver has the third highest heat island effect (the average daily urban-rural summer temperature difference over the past 10 years) in the country.  Green roofs moderate the HIE by cooling ambient air through evapotranspiration. They also provide summer and winter insulation to buildings thereby reducing the carbon footprint. Other benefits include decrease in stormwater contamination, reduction of pollution by filtering the air as it moves across the roof, additional wildlife habitat for birds, insects, spiders and other animals and absorption of noise. While green roofs, especially extensive designs, are expensive, they have been shown to last longer than traditional roofing resulting in long-term cost benefit.

 

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Denver EPA Headquarters Courtesy of Denver Green Roof Initiative

The 20,000 square foot green roof at Denver’s Environmental Protection Agency Region 8 Headquarters  was installed in 2008 in partnership with Colorado State University and other organizations. Using a system of 2′ by 4′ plastic trays, plants were studied for exposure to winter and summer extremes, wind exposure and soil conditions, among other factors. The roof contained four species of Sedums, including Sedum album (white stonecrop), Sedum kamtschaticum (Russian stonecrop), Sedum acre (goldmoss stonecrop) and Sedum spurium (two row stonecrop) and three varieties of Sedum spurium: ‘Dragon’s Blood’, ‘John Creech’ and  ‘Red Carpet”.  According to the researchers, “These plants were selected for visual appeal as well as survivability in harsh environments with temperature extremes, and for their capacity to withstand drought conditions better than most plants.” Another outstanding performer was the brittle prickly pear, Opuntia fragilis. According to Dr. Jennfer Bousselot, “It’s spectacular especially since it has been virtually untouched since the formal study ended in 2010. It has thrived on only light irrigation during the growing season.” Find extensive documentation of the project here.

 

Green roof design addresses many environmental concerns. Will it “take root” in Colorado?  To learn more about green roof design and Denver’s upcoming ballot initiative, here are some additional resources:

National Public Radio: Do Cities Need More Green Roofs?

The Denver Green Roof Initiative (includes ballot initiative)

The Denver Post, March 14, 2017. “Green roofs will benefit Denver but they shouldn’t be mandated”

 

Written by Linda McDonnell, a Denver Master Gardener

 

 

 

 

 

 

 

 

 

 

 

 

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Do Japanese Beetles Prefer Some Roses More than Others?

Colorado roses have been attacked by Japanese beetles for several years, leaving behind ravaged foliage and deformed flowers. Curiously though, some gardeners report that their roses suffer little to no damage from the insect. Are some rose cultivars less enticing to the Japanese beetle than others? This was the focus of Colorado State University’s 2016 observational study conducted at Littleton’s War Memorial Rose Garden. In the first year of this multi-year study, the following rose cultivars were not found to be damaged by Japanese Beetles: Angel Face, Debut, Hondo, Joseph’s Coat, Mardi Gras, Picotee, Popcorn, Prima Donna, Ralph Moore, Singin’ in the Rain and White Lightnin’.

Conversely, the following cultivars were observed to have the highest levels of Japanese beetle destruction: Pink Promise, Honey Perfume Whisper, Love and Peace, Day Breaker, Strike it Rich, Cherry Parfait, Eureka, Starry Night, Rainbow Knock Out, Lady Elsie May, Carefree Delight and June Lover.

Adult Japanese beetles destroy flowers at the same time bees are gathering pollen, making their impact even more significant. For this reason, CSU’s study identified roses with high Japanese beetle susceptibility and high visitation by bees. Topping this list were Rainbow Knock Out, Lady Elsie May and Strike it Rich. Also in this group were Prominent, Home Run, Easy Does It, Apricot Nectar, Gemini, Starry Night, Baby Boomer, Sweet Diana, Julia Child, Cathedral, Betty Boop, Mon Cherie and Cloud Dancer.

Early findings suggest that gardeners may be able to lessen damage to roses by planting cultivars that are less attractive to Japanese beetles. It also underscores the importance of close monitoring and care of plants to reduce the effects on pollination. In the future, additional information on why some cultivars are preferred over others is likely to emerge.

This CSU publication provides comprehensive information on caring for plants infested with Japanese beetles, the larvae stage effecting turf and more. An additional bit of advice – it has recently been found that crushing the Japanese beetle does not attract more beetles. So, while we’ve previously been advised to handpick and drown the insect in soapy water, feel free to stomp on them too. Since they are night feeders, they are easiest to find around dusk, when they are about to feast on your plants.

Written by Linda McDonnell, a Denver County Master Gardener

Note: The study cited in this post was presented to the Denver County Master Gardener Association by Dr. Whitney Cranshaw of Colorado State University in May 2017.

Photos courtesy of http://www.pixabay.com

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TREES, glorious trees

Trees. They are all around us.  In our gardens.  In our parks.  On the street.  Yet we barely notice them most of the time.  Gardeners tend to forget that they are plants like any other.  Non-gardeners tend to regard them as more or less permanent objects in the landscape.

I’ve recently been helping with the Al Rollinger Tree Survey being done by Denver Botanic Gardens and The Denver City Forester’s Department.  (For more information on this, see www.botanicgardens.org/rollinger-tree-collection-50-year-survey-project.)  This has taken me to different parts of the city, looking at trees in yards and on the street.  For each tree in the project we identify the tree, measure its diameter and height, assess condition, take a photo and get the GPS location. This close examination has given me a new appreciation of these giants of the plant world.

Denver is at the western edge of what was once short grass prairie all the way to Kansas City.  Trees are not native to this landscape apart from the odd plains cottonwood near water.  All the trees planted and growing in our city are imported here, whether from the higher ranges in the mountains (pine, spruce, aspen) or from the north and east (maples, oaks).

Why plant and grow trees?

Yes, it can be difficult to grow healthy, long-lived trees here.  Too little water, alkaline soil, heavy clay, too hot in summer, too cold in winter, traffic pollution, concrete and blacktop suffocating roots.  These are the same problems that challenge us in our back yards as we try to get our shrubs and flowering plants to perform for us. But with a little care and attention, we can grow healthy trees. Just look at the many benefits trees bring:

Environmental/Health

  • Provide oxygen
  • Reduce carbon dioxide levels
  • Improve air quality through absorption of pollutants
  • Absorb and retain water to reduce run-off and delay onset of peak flow (flooding)
  • Reduce soil erosion
  • Improve capacity of soil to absorb water
  • Provide animal, bird and insect habitat
  • Reduce noise levels
  • Reduce stress
  • Reduce UV exposure

Energy

  • Shade and cool our homes and streets
  • Save energy (natural cooling through shade v. AC)
  • Provide wind breaks

Social

  • Increase property values and reduce crime
  • Improve walkability of neighborhoods
  • Provide beauty

Get to know our trees

You can find out about every single tree growing in the street and public rights of way in Denver by typing in an address in the city’s “Treekeeper” program at http://beasmartash.org/do-i-have-an-ash-tree/interactive-map.  When I walk the dog around the neighbourhood, I look up now and try to identify the trees I walk by (or underneath).  If I don’t know one, I take a note of the address and check on the Treekeeper when I get home. (Because of the vast amount of data involved, the program doesn’t work well on a mobile device.)

Some trees are “champions”. These are trees that have attained a large size (based on species) through girth, height and crown size.  You can find out about Colorado State Champions here www.coloradotrees.org/wp-content/uploads/2016/06/2016-Website-Champs_Alpha.pdf and National Champions here www.americanforests.org/explore-forests/americas-biggest-trees/champion-trees-national-register/. 

Choosing and buying a tree

A tree can be a big financial investment and selecting the appropriate tree is very important if you want it to not just survive but to thrive for many years.  The CSU Extension Service publishes a very helpful list of trees recommended for the front range. You can find it here: www.extension.colostate.edu/docs/pubs/garden/treereclist.pdf

The non-profit organisation, The Park People, has a scheme called Denver Digs Trees for selling street and yard trees at subsidised prices (or even for free in some locations) every year.  The trees they sell are all considered suitable for Denver. You complete an application form in January or February and the trees are distributed in mid-April.  They will even come and plant your tree for you if you need help. You can find them here:  www.theparkpeople.org/Programs/DenverDigsTrees.aspx

Look for trees in Colorado nurseries and garden centers which grow their own trees.  A tree which started life here is likely to be better adapted to Colorado growing conditions than one imported from another state.

Before you plant

When planting a tree whether in your yard or the street, you need to get the position of all utility lines checked before digging . You can get the utility lines checked for free by calling 811.  You also need a permit from the City Forester before you plant a tree in the street i.e. the public right of way.  The permit is free and can be obtained by email. See here for details:

www.denvergov.org/content/denvergov/en/denver-parks-and-recreation/trees-natural-resources/forestry-trees-/property-owner-resources.html

Tree problems

Like all plants, trees can have problems.  Pests and diseases or hazards caused by natural events, like storm damage.  Often problems stem from human actions.  Improper planting, insufficient or too much irrigation, damage from garden tools like mowers and weed-whackers, root damage from nearby construction, damage from staking and guy wires, pet damage, root damage from landscape fabric or inappropriate mulching e.g. river rock.

Emerald Ash Borer

The biggest problem facing trees in Denver right now is the threat of the Emerald Ash Borer (EAB). This pest came from Asia where their ash trees are immune to it.  Unfortunately, American ash trees are not.  Its presence has been confirmed in Boulder since 2013 and in Longmont since 2016.  It threatens to wipe out all the ash trees in Denver if (when?) it gets established here.  That’s 1 in every 6 trees in Denver or 1.45 million trees.  For information and advice about EAB go to http://beasmartash.org/.

To try and mitigate the effect that EAB will have on our city trees, the City Forester’s Dept, in association with The Park People’s Denver Digs Trees program, is offering new street trees now for FREE.  By planting in advance of the arrival of EAB, the aim is to mitigate the effect of the EAB and increase diversity in the city’s tree population. You don’t need to have an ash tree already or any kind of street tree, just room to plant a new one.  To apply for a new street tree, go to www.beasmartash.org/what-can-i-do/apply-for-a-tree/.  They will even plant it for you!

Learn more about trees and get involved

The Park People run a program with Denver’s City Forester’s Dept which trains volunteers to become Community Foresters.  Volunteers assist the City Forester’s Dept by becoming qualified to lead and participate in tree planting and tree care projects in their neighborhoods.  Courses are run every year.  More information can be found at  www.theparkpeople.org/programs/communityforester.aspx

Get more information about trees

You can find useful information and get advice on all aspects of trees from the following:

Your local City Forester (arboreal inspector) – find him/her at www.denvergov.org/content/dam/denvergov/Portals/747/documents/forestry/forestry-inspections-districts-map.pdf

CSU Extension Service ‘Ask an Expert’ – ask.extension.org/groups/1955/ask

Ask a Master Gardener – www.cmg.colostate.edu/ask-cmg.shtml

The Park People – www.theparkpeople.org

The Colorado Tree Coalititon – www.coloradotrees.org/

A professional arborist – see the list of arborists licensed to operate in Denver at www.denvergov.org/content/dam/denvergov/Portals/747/documents/forestry/DPR-Forestry_current-licensed-contractors.pdf

Look up, learn more and enjoy our trees!

 

Anne Hughes/A Denver County Master Gardener

Photo by Anne Hughes

 

 

 

 

Grandma Always Said: How To Research Gardening Questions Effectively

IMG_20170228_123941189“Roses won’t do any good without blood.” my grandma always told me as, small girl, I watched her dump buckets of chicken blood over the roots of her roses in rural Wisconsan. Of course, she also told me roses planted during the waning moon would die straight away.
My grandma’s gardening practice was full of these details: fish heads in the holes dug for new lilacs, red thread tied around apple branches to protect them from blight. I still keep her copy of The Farmer’s Almanac fondly among my folklore books….but I don’t get my garden advice from it.
Gardening is a mystical business, half art and half science. Folklore abounds, and any gardening question will have five answers, three of them odd or downright off the wall.
The internet has not helped this issue in the slightest. Type ‘kill weeds in the garden’ into Google and you’ll get hundreds of answers, ranging from reputable to rapaciously folksy to alarming in the extreme. For example, I once read a recommendation for turpentine and salt to kill prickly lettuce around peonies. You get the idea….
So how does a gardener sort through the chaff to find the information they need in this muddle?
Here’s a quick checklist of the Four Research Rules, to help you vet your sources!

Reputable URL

When doing a web search, focus on URL’s with an ‘.edu’ ending. This means that an educational body has collected, researched and put out the information for public education and it should be fairly unbiased. If the site ends in .com, chances are a company is involved, and that can skew answers towards ‘buy this to fix your problem!’ The research is also more reliable on educational websites than on your garden-variety blog.

Reliable Information: The Most Accurate Information For Today

As with any other field, information on best garden practices changes with time. I generally ensure that my garden books are no older than 1970, and prefer books printed in the 90’s or later.

Repetition: It Makes Reputation

If only one source or one gardener is talking about a method, you might want to be wary. Best practices tend to spread, so if there’s no existing research on a method of doing something, you might want to try it as an experiment but don’t  rely on it until it’s proven.

Research!
If your source isn’t citing other sources or is using anecdotes to endorse a recommendation, buyer beware! Look for solid research, sources that you can look up yourself and references to specific studies, field trials, or specific experimental examples of the product/method/concept being applied. Some garden books are written poetically and that’s fine, but make sure there’s solid research under the fine words.

Happy garden researching!

-Olivia Wylie, Master Gardener

Five Annuals for the Garden

Perennials, shrubs and trees are the undisputed stars of landscape design, providing structure, texture, longevity and nourishment for pollinators (especially native plants). But annuals, too, can play a valuable role for their ability to fill out a maturing garden and infuse color when perennials have finished blooming.  Design-wise, these “one season wonders” offer a chance to change things up from year to year.  For the short-term renter or impatient gardener, annuals offer speedy gratification.

If you’re thinking “petunias, geraniums, marigolds – been there, done that,”  keep reading. Here are five other easy to grow annuals for sunny locations which will thrive when planted among plants with the same moisture needs.

CLEOME

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Cleome, or spider flower, is the tall kid in the back row. Intricate, long-lived  blossoms (6+ inches across) in shades of white, purple or pink will attract hummingbirds and pollinators. Seed pods create interesting tendrils. Xeric once established, plants can reach 5′ tall by the end of the summer. Let some seed drop and they may return next year.

RUBY MOON HYACINTH BEAN  (Dolichos lab lab)

Move over wisteria and clematis, this Plant Select vine is a show stopper. Burgundy tinged foliage with dark stems which support abundant amethyst flowers. In late summer, this vigorous vine is covered with large dark purple bean pods. Grow it on a trellis, let it climb a fence or freely mound in the full to partial sun garden.  Learn more about Ruby Moon here.

LOVE-IN-A-MIST (Nigella damascena )

Love-In-A-Mist sounds like the title of a romance novel, doesn’t it? This delicate, tough plant bears 1″ blue, white, lavender or bicolor flowers which bloom atop 8″ to 12″ finely cut “misty” foliage. It is best grown from seed but occasionally available as seedlings. The bloom morphs into an oval, burgundy striped seed pod which rivals the flower in beauty. Let it reseed for next year, but also treat yourself to some flower and seed pod cuttings.

COSMOS (Cosmos bipinnatus)

Single 2″ to 3″ daisy-like flowers seem to dance above 24″ finely cut foliage. Popular varieties come in pastel/white mixtures; a newly introduced dwarf cultivar is available too. Cosmos can be started from seed or purchased in 4 packs. Don’t let their delicate appearance fool you, they prefer low water conditions and strive in the summer heat. One caution – over fertilizing results in lush foliage and far fewer flowers. Cosmos are a long-lived cut flower, excellent planted in mass and attractive to birds. Will reseed easily, occasional deadheading keeps them at their best.

SUNFLOWER (Helianthus)

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Big and little kids alike delight in watching sunflowers grow. Sow some seeds in the spring and you’ll thank yourself later – so will the birds. If you prefer, keep your eyes out for sunflower transplants at the garden center. Visit Smart, Smiley Sunflowers for information on the wide variety of cultivars, including shorter and multi-branching options.

Written by Linda McDonnell, a Denver County Master Gardener

Photo credits:

Ruby Moon Hyacinth Bean: Plant Select

Sunflower: Jodi Torpey, Denver County Master Gardener

Cosmos, Cleome and Love-In-A-Mist: Pixabay.com, a source of royalty free images

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The Season Of Vigilance: Noxious Invasives, Introduced Weeds And You

-Olivia Wylie, Master Gardener Denver

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The saying goes ‘a weed is a flower whose virtue hasn’t been found yet.’
But you have to wonder with some of the weeds in the garden. What exactly, you think as you sweat and tug, is the virtue of bindweed’s strangling grip on other plants and your garden? What’s the virtue, you think with nervous venom as you pull on your gloves, of a spurge that can give you blisters, kill your dog, and is invasive?!

Unfortunately, the virtues of these plants are exactly what makes them weeds. Adaptability. Tenacity. Ability to survive harsh conditions. It sounds like a compliment when you’re reading a garden catalog, but with the wrong plant in the wrong place, it’s a recipe for disaster on a garden-wide, city-wide or even state-wide level.

Sadly this disaster has played out many times, and today we carry the burden of our forbears’ horticultural mistakes across the country. To combat this issue, a Federal Noxious Weed act was passed in 1974, and our own Colorado Noxious Weed Act was passed in 1996. The Act supports the creation of programs to combat the invaders, and the Department of Agriculture maintains a list of plants to look out for called the Colorado Noxious Weed List.

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This list is invaluable as a resource, and is broken down into several sections. Quoting from the Colorado Department Of Agriculture,

List A Species in Colorado are designated by the Commissioner for eradication.

List B Species are species for which the Commissioner, in consultation with the state noxious weed advisory committee, local governments, and other interested parties, develops and implements state noxious weed management plans designed to stop the continued spread of these species.

List C Species are species for which the Commissioner, in consultation with the state noxious weed advisory committee, local governments, and other interested parties, will develop and implement state noxious weed management plans designed to support the efforts of local governing bodies to facilitate more effective integrated weed management on private and public lands. The goal of such plans will not be to stop the continued spread of these species but to provide additional education, research, and biological control resources to jurisdictions that choose to require management of List C species.

Watch List Species that have been determined to pose a potential threat to the agricultural productivity and environmental values of the lands of the state. The Watch List is intended to serve advisory and educational purposes only. Its purpose is to encourage the identification and reporting of these species to the Commissioner in order to facilitate the collection of information to assist the Commissioner in determining which species should be designated as noxious weeds.’

But we all know what happens when we leave the work up to the government and sit on our laurels. It’s up to every gardening citizen to know your noxious invasives, your invasives, your introduced weeds and what to do about them!

Know Thy Enemy

We could spend entire articles on the exact definition of invasive species, and in fact a wonderful white paper on the subject can be found at this link. But here’s the skinny.

niNoxious Invasive- the long winded definition is quoted from the 1974 Act, and runs ‘Noxious Weed means any living stage, such as seeds and reproductive parts, of any parasitic or other plant of a kind, which is of foreign origin, is new to or not widely prevalent in the United States, and can directly or indirectly injure crops, other useful plants, livestock, or poultry or other interests of agriculture, including irrigation, or navigation, or the fish or wildlife resources of the United States or the public health.’

Put plainly, not only will Noxious Invasives make you livid, they can make you sick. These are the true thugs of the plant world. Generally these beasts will be found on the Commissioner’s A list. These include vile things like Myrtle Spurge/ Donkey Tail Spurge, Euphorbia myrsinites. Originally introduced as a ‘lovely and tenacious rock garden addition’ (a direct quote from an old seed catalog, the company shall remain unnamed!)  it was indeed tenacious. TOO tenacious. And if you decide to pull the stuff, it retaliates with sap that causes painful blisters. Get it in your eyes? You’re taking a trip to the ER my friend. Dogs that encounter the sap can actually die. Not such a great addition after all, and if you see it in your garden it needs to be eradicated by (almost!) any means necessary. Before you tackle it, PLEASE pull on goggles, a long sleeve shirt and pesticide-grade gloves. In fact, I prefer to pull on a thin pair of fabric gloves and my nitrile pesticide gauntlets go on over those. You can never have too much protection.

dtInvasive Species-  an invasive species is best defined as a non-native plant that could cause harm to the native ecosystem by competition pressure. When you pull prickly lettuce before it smothers your lovely little columbines, that’s a perfect example. These plants are tougher, more prolific, easier spreading or in some way advantaged over other plants, and if allowed will run roughshod over our native flora.
Dalmatian Toadflax is the classic example. I’ve taken out of town friends on a drive through the foothills and heard them exclaim ‘oh look at that yellow field!’ I look over and give a heartfelt groan, because I know that field has nothing living in it save a single invading species that has choked out native plant life.

isIntroduced Species-Where list A Noxious Invasives could be compared to a plant felony, plants that fit the Introduced Species are more of a misdemeanor: they’re trouble, but not ecological disaster. Defined as ‘an organism that is not native to the place or area and has been accidentally or deliberately transported to the new location by human activity’ in the 1974 Act, they’re your neighbor’s old mint bush sending shoots into your yard. In my Capitol Hill neighborhood, the quintessential example is the Cap Hill Weed (no not THAT weed),Campanula rapunculoides or Creeping Bellflower. Local lore says it was introduced in the 1920s to grace the great old mansions that once stood in their majesty along these streets, and it’s been with us ever since. It wanders from garden to garden in the older parts of town, sneaking under trees and into small areas, worming into bare spots in the grass and gaining a foothold most anywhere. Some people have simply accepted it as a garden plant like their grandmothers did, but most of us fight it tooth and nail because we’d like to have a garden with more than one plant in it!

Fighting The Good Fight

Delving into reclamation and eradication tactics for species that are toxic, invasive or introduced pests is a paper in itself, and many have been written. The Colorado Noxious Weed Species List has details on the treatment of every species it lists. But here’s some general tips.

  • Safety First. Wear gloves, wear long sleeves, wear safety glasses or goggles if you run any risk of getting poked in the eye or sprayed with sap
  • Get The Root!  Pulling does little good if there’s a root stocked with nutrients ready to shoot up new leaves under there. If you use pesticides, make sure your choice specifies ‘kills the root’.
  • Tenacity Is A Virtue. Don’t get discouraged if the plants come back again and again. keep using your favorite eradication method, and you can wear these invaders out!

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Sheet Mulching Re-visited

Last week’s blog included a link back to our October 2016 blog on experimenting with sheet mulching (also known by some as “lasagne gardening”) http://wp.me/p5JEJY-YZ so I thought we ought to re-visit and see how that worked. Sheet mulching is the layering of different kinds of compostable garden waste (sometimes with old newspapers or cardboard as well) on the surface of poor garden soil. The aim is to quickly add organic matter to the existing soil, improving drainage, water retention and fertility.

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I had several questions in my mind last fall when this experiment was carried out:

1. Will the cardboard decompose?
2. Is the “green” and “brown” balance right?
3. Will the raccoons and skunks churn it all up?
4. Will there be a crop of new weeds from the imported materials?
5. Will the cold Colorado winter simply stop any decomposition from taking place?
6. Will there just be a smelly slimy heap to remove next spring?
7. OR, will we have achieved that elixir of gardening – fertile, well-drained, moisture-retentive soil???

The experiment has been going on for some eight months now and these are the answers, so far:

1. YES. Some digging about at the base of the layers revealed no sign of cardboard except for a few stray bits of plastic tape that didn’t get removed when I broke down the cardboard boxes.
2. Probably YES. Though close inspection revealed that in some parts the grass clippings were laid too thick and would have done better if they’d been mixed in more with the dried leaves.
3. NO. Apart from a few little exploratory digs by some critters, the layers remained intact.
4. NO. Initially there was some germination from seeds (unidentified grass/cereal) which were in the chicken coop material I used, but these were easily pulled in the first couple of weeks. Since then not a single weed has appeared.
5. NO. Digging into the layers revealed pretty well composted good, brown material though not everywhere. Lots of worms too. Straw seems to have been the hardest to break down and is still recognizable in some places.
6. NO. See 5.
7. Well, MAYBE ….

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The native grey clay soil is still there beneath the sheet mulch

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Well on the way to being compost

There is no doubt that we now have deep layers of composted garden waste on our borders. The layers have not been totally absorbed into the soil below. They have shrunk in depth by a couple of inches which is probably mainly due to gravity and the reduction of air pockets. I accept that these borders may remain as “raised” borders for some time.

So, what happens next? I expect these sheet mulched borders to continue to decompose over the summer and, perhaps, by next spring will no longer be “raised”.

But I can’t wait until then to get new plants in.  Already, I have a planted a Japanese maple and some hellebores in one of the beds (both should benefit from the rich compost.  I dug holes in the compost layers, put in some native soil from elsewhere in the garden and planted and watered.

I was concerned that the compost itself would not hold the plant roots securely which is why I mixed in garden soil from elsewhere to give weight. It will also provide mineral nutrients that may not be present in the compost/mulch. Now, some six weeks later, the new plants are all well rooted and looking good.

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Japanese maple and hellebores just planted

So, is it worth doing? I’m giving the experiment a qualified “yes” at this stage.

I think it works for areas that have been neglected or are being cultivated for the first time. There is an initial effort in gathering the materials and building the sheet mulch layers, but then you just sit back and wait.

Does one big “hit” of compostable material work better than cumulative additions over the years? I don’t know. Time will tell as I compare these borders with others in the garden. Certainly, I got a lot more compost onto the borders than I could generate annually from my compost bins. (You don’t get a lot of kitchen waste from two people; and a modest-sized, young garden doesn’t produce much waste either.)

It might have been less work to simply go out and buy bags of compost from the garden center or big box store. That would have been expensive (my materials were all free). There are no regulations on what goes into bagged compost for retail sales.  At least I knew exactly what was in mine.

Aside from these thoughts, there has definitely been a great sense of satisfaction in doing the experiment.  It was interesting.  It was good exercise.  It was free.  I turned what other people thought was just rubbish messing up their yards into useful, re-vitalizing material for our garden and plants.

Anne Hughes/A Denver County Master Gardener