Plant Sale in Denver this Weekend!

By Alexis Alvey, Horticulture Agent, CSU Denver Extension

The Denver Master Gardener 9th Annual Spring Plant Sale will take place this weekend, May 17th and 18th!  On Saturday, doors will open early at 8:00am and stay open till 3:00pm.  On Sunday, the sale begins at 10:00am and ends at 3:00pm.   The sale is located in front of the CSU Denver Extension office at 888 E Iliff Ave, Denver 80210, in the northeast corner of Harvard Gulch Park, with the cross-street being Emerson.

The Spring Plant Sale offers a unique variety of heirloom and modern tomatoes, sweet and hot chili peppers, select vegetables and herbs, and annual and perennial flowers.  Denver Master Gardeners have been working hard all spring in the City Greenhouses in Denver City Park, operated by Denver Parks & Recreation, growing almost all of the veggies and herbs available at the plant sale.  It has been a great opportunity and hands-on learning experience for the Master Gardeners.  Working alongside Parks & Rec staff, they began seeding in March and have provided the tender loving care that each plant deserves.  The plants are now super healthy and ready to be taken to your home!  Below is a list of all the varieties being grown by the Master Gardeners.  The remainder of the plants are obtained from Colorado nurseries and helps support the local horticulture industry.

At the Spring Plant Sale, Denver Master Gardeners will help answer any of your gardening questions and will help you choose the best plant varieties for your particular needs.  All proceeds from the sale support the CSU Denver Extension Horticulture Program.


The Spring Plant Sale is a great community event, so make sure to stop by the other booths including Plant-A-Row for the Hungry where you can get free seeds!, the gently-used gardening items for sale booth, the Rosedale-Harvard Gulch Neighborhood Association, and the 4H Kids-Grown booth!  For more information, call 720-913-5270.  The event is rain or shine (or snow!).  Cash only, please.  See you there!

Why Trees Are Frickin’ Awesome

Alexis Alvey, Horticulture Agent, CSU Denver Extension

I have always loved trees and I’m sure that many of you gardeners out there feel the same why.  I have always been enchanted by the beauty and power that they convey, their leafy greenness and tall trunks reaching up towards the sky.  I could go on, but I won’t since I know that I’m preaching to the choir.  Shockingly, there are some folks out there who don’t feel the same way and who don’t like trees (insert audible gasp here)!  Perhaps with a little more convincing, we can get more people to understand the need for trees so that our city officials can make the correct decisions about our urban forest.  So here are some awesome and quantifiable benefits of having trees in our cities:

•         According to a study by the US Forest Service that evaluated the benefits of community trees, for every dollar that a city invests in a community tree program, trees will give back $1 - $2 in environmental benefits.
•         Shaded streets are 10-40 degrees Fahrenheit cooler since paved areas store about half the sun’s energy.  Tree evapotranspiration accounts for an important percent of this cooling effect. 
•         A well-placed tree can reduce home cooling costs by 10-30%.  In summer, trees block 70-90% of the sun’s radiation on a sunny day.  Plant trees so that they can shade air-conditioning units and west-facing walls.
•         Trees improve air quality by removing ozone, particulate matter, nitrogen dioxide, sulfur dioxide, and carbon monoxide.  The Forest Service’s UFORE model estimates 1200 – 1800 tons of atmospheric contaminants are removed annually in a major city in thee US by their urban forest.
•       One tree can absorb the same amount of carbon in a year that a car produces while driving 26,000 miles.
•         A large percentage of paved surfaces in cities can contribute to flash flooding in storm events.  By intercepting precipitation, trees reduce the speed and quantity of raindrops hitting the ground.  One study found that in a city with a tree canopy cover of 22%, runoff was reduced by 7% by those trees.  There is also a reduced cost in constructing stormwater retention ponds.

So that’s quite a lot of environmental benefits that trees provide!  But did you know that trees also provide psychological and social benefits as well?  Nature has a restorative and calming effect on human beings.  (If you want to look deeper into this subject, take a gander at Richard Louv’s book, Last Child in the Woods.)   Some social benefits of trees include:

•         A landmark study conducted in the mid ‘80s found that hospital patients recovering from abdominal surgery who had a view of a wooded scene vs a brick wall out their windows recovered more quickly, required less pain medication, and had fewer complications.  Postoperative hospitalization was reduced by 8.5%.
•         A study in 2001 found fewer violent and property crimes occurred in areas of dense trees and grass.  The authors concluded that plants may mitigate the psychological precursors to crime, such as irritability, inattentiveness, and impulsive behavior.  Landscape plants may increase the perception of safety of inner-city residents by providing an open and inviting place to congregate.
•         A study in Massachusetts found that trees added 5-15% to the sale price of hypothetical homes on lots with and without trees.
•         The US Forest Service reports that consumers spend 12% more for goods and services in tree-lined business districts.  Visitors also tend to shop more frequently, stay longer, and spend more for parking.

Trees are really great with all their environmental, psychological, and social benefits!  If you want to find out how much in benefits your tree is providing, check out the National Tree Benefit Calculator at www.treebenefits.com.  For instance, the calculator estimates that a 14 inch Kentucky Coffee Tree gives back $100 per year in benefits.  Pretty frickin’ awesome!!!

United in Orange!

Alexis Alvey, Horticulture Agent, CSU Denver Extension

Even though it’s January, you can show your Broncos support all season long with these orange-hued flowers!  Plant them in the spring in mid-May after the risk of frost has passed, and all your neighbors will know what a dedicated fan you are!

• Agastache aurantiaca

-          Agastache aurantiaca, or Coronado® Hyssop, is an enduring perennial native to the southwest.  Its spikes of muted orange flowers add subtle color to the garden in late-summer through fall.  Just as alluring is its fine, silvery foliage which highly fragrant.  It grows well in moderate to dry soil conditions, in partial to full sun.  In 2001 it was chosen as a Plant Select winner and has certainly proven its merit in Colorado gardens.  Will grow to 15 inches tall by 12 inches wide.

• Coreopsis ‘Jethro Tull’

-          Coreopsis, or Tickseed, has become a staple in the low-water garden.  ‘Jethro Tull’ is more compact and longer-blooming than many other Coreopsis cultivars.  The golden-orange flowers look superb in any garden border.  Be sure to plant in full sun.  Will grow up to 18 inches tall by 24 inches wide.

• Gaillardia ‘Mesa Bright Bicolor’

-          Gaillardia, or Blanket flower, is typically a perennial, but this beauty has more of an ephemeral nature.  Don’t expect ‘Mesa Bright Bicolor’ to overwinter – instead, treat it like an annual.  The vivid orange and red-colored flowers were striking enough to turn many heads when it was planted at the CSU Annual Flower Trial Garden in 2011.  This cultivar is compact with medium green foliage and will grow to 14 inches tall by 20 inches wide.

Photo source: www.flowertrials.colostate.edu

• Gazania krebsiana

-          Gazania krebsiana, or Tanager® Gazania, is a low-growing, drought-tolerant, tender perennial.  A South African hybrid, it’s been proven to thrive in Colorado’s tough growing conditions and is a 2003 Plant Select winner.  It may reseed moderately in zone 5, and in protected sites is winter hardy.  Season-long, bright orange flowers will surely dazzle your garden!  This Gazania will grow to 4 inches tall by 10 inches wide.  Be sure to plant in full sun.      

Photo source: www.plantselect.org

Let’s unite in orange and cheer on the Broncos to a Super Bowl win!!!  For more information on Plant Select, visit www.plantselect.org

2013 - Out With A Bang!

Alexis Alvey, Horticulture Agent, CSU Denver Extension 

It is the end of the year, that time when the phone is silent, the e-mail box is noticeably empty, and anyone walking into our office is more interested in free Christmas cookies than asking gardening questions.  I am always grateful for this time period when the Horticulture Program can take a much-needed breather before heading full-swing into Master Gardener training in January.  Reflecting on 2013, here are just some of the awesome things that the Denver Master Gardeners and the Denver Horticulture Program have accomplished!

- Nearly 5,000 volunteer hours were donated in 2013 by Master Gardeners to 44 gardening projects throughout Denver!

- Master Gardeners answered nearly 7,000 gardening questions this year!

- 430 pounds of produce were grown in 2013 in our Vegetable Demonstration Garden and donated to the St. Francis Homeless Shelter.

- The most successful Denver Master Gardener Plant Sale ever!  Our two-day sale sold-out!

- A new Native Plant Garden & CO State Children's Home Memorial was installed in front of the Denver Extension office.

- First Native Plant Master class hosted by CSU Denver Extension.

- Master Gardeners taught hands-on gardening sessions at the Colorado Governor's Mansion to young adults who are recovering from substance abuse.  There were five "graduates" of the program and eight total participants.

And also of note: 

- CSU Denver Extension provided help with the Emerald Ash Borer delimitation survey in Boulder.

- 14 new Master Gardeners joined our team of 122 active Master Gardeners here in Denver.

- First statewide webinar partnering with the CSU Alumni Association, and

- New Master Gardener volunteer project at the Haven in Fort Logan which led gardening workshop for women there recovering from substance abuse.

Thanks to all who have helped make this such a wonderful year!  We are looking forward to a fantastic 2014!!  Happy holidays!

Native Plants for Sustainable Gardens

Alexis Alvey, Horticulture Agent, CSU Denver Extension

I hail from the East Coast and moved to Denver last year.  By no means am I an expert yet on Colorado native plants, but having gardened all my life, I AM an expert on making gardening mistakes and learning how to fix them.   And during the past year, I’ve learned that there are a lot of things that can go wrong when trying to garden in Colorado!

Like many Coloradans, in my spare time, I enjoy going up to the mountains and going hiking or trail running.  I love checking out the vegetation and the stunning landscapes that Colorado has to offer.  And I always think, oh, wouldn’t it be so awesome if I could recreate this in my own backyard!  How nice it would be to have wildflowers blooming in my garden like these on the trail to Mt. Evans….  

Or how relaxing it would be to create a meadow instead of lawn like this alpine meadow near Dillon….

Or how enchanting it would be in the fall to have a grove of aspen outside my window like these at Willow Creek Reservoir, near Granby.  

And based on all the inquires we get at the Denver Extension office, I know that I am certainly not alone in my desire to recreate a little piece of natural Colorado in my backyard.  But unfortunately, what we want, we often do not get, especially when it comes to native plant gardening.  For example, this aspen which is in the front yard of an avid Denver gardener is nearly dead. 

To learn some tips on how to garden successfully with native plants and avoid common pitfalls, click on the link below to listen to a free, recorded webinar I just did on this topic!

https://cc.readytalk.com/cc/playback/Playback.do?id=gp3stu

Gatsby Gardens

Posted by: Alexis Alvey, Horticulture Agent in Denver County

I'll admit that I am a dork at heart.  But unlike most of my colleagues, I don't just geek-out about plants - books and American literature will induce the same type of nerdy enthusiasm.  (And don't even get me started on plant books!)  So when I found out that a new film was being made about The Great Gatsby, a book that I've read not once, not twice, but three times, I pretty much flipped-out.  (And Leonard DiCaprio as Jay Gatsby was a huge bonus!)  I was super-excited to see Gatsby's enchanted gardens, where "men and girls came and went like moths, among the whispering and the champagne and the stars" on the big screen.  Did the exquisite gardens live up to the magnitude of greatness I had created in my head?  Well, unlike the critics, I thought Baz Luhrmann's over-the-top directing did a great job of conveying the splendors and excesses of New York during the Roaring Twenties.

Being that Colorado is a tinderbox and entrenched in wildfires at the moment, I thought I'd use this blog post to provide a brief reprieve by describing some of the lush, green, Gatsby-esque gardens I've had the pleasure of visiting on Long Island, NY.



The front entrance to the Old Westbury Gardens mansion

The Long Island Gold Coast, which encompasses Gatsby's legendary West and East Eggs, occupies the North Shore of Nassau County, from Great Neck to Huntington.  Over a dozen estates, once owned by some of the most famous people of NY, have been converted to public use.  Most of these mansions were built from 1890 to 1925, and they were the playgrounds of the great barons of the Industrial Revolution, including the Vanderbilts, Roosevelts, Whitneys, Pratts, Morgans, and Woolworths.

Old Westbury Gardens is one of my favorites.  Located in Old Westbury, it was the home of John S. Phipps, his wife, Margarita Grace Phipps, and their four children.  John’s father was Andrew Carnegie’s business partner, and as such, he was heir to the US Steel fortune.  Completed in 1906, the magnificent Charles II-style mansion sits amid 200 acres of formal gardens, landscaped grounds, woodlands, and ponds.  It has been open to the public since 1959.  Perhaps you have seen it yourself, because it has been the site of many films, including Cruel Intentions, Hitch, and Gossip Girl.


Old Westbury Gardens

One of the key questions that Old Westbury Gardens wrestles with, is how do you maintain a historic landscape in the modern age that is for public use?  What happens when old, magnificent trees start to decline and invasive pests come in?  Old Westbury Gardens has invested great amounts of time, effort, and financial resources for tree preservation.  There is an old allee of European Lindens (Tilia x europaea) that traverses the property from the ornate entrance gate to the mansion.  If one tree goes, the whole effect of the allee is compromised.  These trees are routinely pruned for deadwood, and an integrated pest management program has been created for them, which focuses on improving the soil environment.

Another former Gold Coast mansion and now public garden has taken a different approach to a similar problem.  Planting Fields Arboretum is located in Oyster Bay on Long Island and was the "country cottage" of William Robertson Coe and Mai Rogers Coe.  William made his fortune in marine insurance and Mai was the daughter of one of the partners of Standard Oil. 

Planting Fields Arboretum pool

Their 65 room Tudor Revival cottage, Coe Hall, was completed in 1921.  The arboretum is comprised of 409 acres of greenhouses, rolling lawns, formal gardens, woodland paths, and plant collections.  At the time, the grounds were landscaped by the famed Olmsted Brothers. 

As a child growing up in Fairhaven, Massachusetts, Mai Coe was particularly fond of two European purple beech trees (Fagus sylvatica) on the grounds of her home.  So, when she moved to Long Island, she decided to bring them with her.  In December 1915, the two trees were moved by barge across the Long Island Sound to Oyster Bay, where they were dragged on skids by teams of horses and a steam roller.  Each tree was about sixty feet in height and about forty feet wide, and each weighed more than 28 tons.  Only one of the trees survived the transplanting.  For ninety years, the one purple beech tree towered majestically in front of Coe Hall, cooling the building in summer and tempting visiting children to climb it's enormous branches.  Then, in about 2005, the tree finally succumbed to disease and had to be removed.  But before it was cut down, the foresighted Arboretum Director, took a cutting from the original tree.  The cutting now stands about twenty feet tall, and in a few decades will become the majestic tree that its parent once was. 

Planting Fields beech tree cutting

Perhaps The Great Gatsby will inspire you to someday visit the gardens of Long Island's Gold Coast.  But in the meantime, we can focus on our own backyards and dream of the grandeur that once was.  Personally, I'm just glad I will never have to orchestrate the moving of a 28 ton tree!

"Promise America" to Not Move Firewood!

Alexis Alvey, Horticulture Agent, CSU Denver Extension

What do baseball bats, bugs, and ash trees all have in common? (And no, this is not some lame, bar room joke.)  Well, they are all part of the "Promise America" campaign initiated by the US Department of Agriculture.  This campaign has been launched to educate everyday homeowners and gardening enthusiasts alike about the invasive insect pest called the Emerald Ash Borer (Agrilus planipennis) which is killing literally millions of ash trees across America.  There are a handful of different species of ash trees that are native to the Midwest and the East Coast that are commonly planted as great urban street trees throughout the US, including Denver.  Wood from ash trees has traditionally been used to make baseball bats.  Unfortunately, all of our native ash, including White Ash (Fraxinus americana) and Green Ash (Fraxinus pennsylvanica), which are the two species planted in horticulture, are completely at the mercy of Emerald Ash Borer.    This tree-killing beetle was first identified in the US in 2002 near Detroit, Michigan and is native to eastern Russia, northern China, Japan, and Korea.  No one knows for sure how or when it got here, but most likely in the 1990s it came to the US in ash wood used for stabilizing cargo in ships or for packing or crating heavy consumer products.  It has now spread into seventeen additional states and two Canadian provinces and continues expanding its range.  Its spread has been accelerated by the movement of infested firewood.  Last year it was discovered in Kansas for the first time, and people are worried that it will soon be in Colorado.  Denver Parks & Recreation’s Forestry Division will begin monitoring for Emerald Ash Borer for the first time this season. 

Photo: Adult Emerald Ash Borer 

(Leah Bauer, USDA Forest Service Northern Research Station, Bugwood.org)

The Emerald Ash Borer is actually a relatively pretty insect (I say relative, because in my opinion all insects are kind-of gross.)  The adult beetles are a bright, metallic green, a half-inch long, and have a flattened back. But the problem is not the adult beetles, it is their larvae.  The larvae are a type of flatheaded borer.  (By the way, “You are such a flathead!!” makes for a great insult!)  Larvae hatch from eggs laid within bark crevices and under bark scales in the spring.  They chew through the outer bark of the tree and into the cambium where they feed in the phloem interrupting the flow of nutrients within the tree, ultimately girdling it. 

Signs and symptoms of Emerald Ash Borer infestation are yellowing leaves on branches and then dieback generally in the top of the tree canopy first.  Sprouting from the base of the trunk can also occur.  If you are lucky and look very very carefully, you may see small holes in the trunk that are 1/8” in diameter and that are D-shaped.  Complete defoliation and tree death typically occurs within 2-3 years.   

Photo: Green Ash dead due to Emerald Ash Borer 

(David Cappaert, Michigan State University, Bugwood.org)

Unfortunately there is no simple cure for Emerald Ash Borer.  This little beetle has had an enormous economic and ecological impact.  The devastation of the insect is remarkable - over 53 million ash trees have died or are dying from the borer and all of North America's 7 billion ash trees are at risk.  It is estimated that up to $26 billion has been lost due to the borer in just four Midwestern states.  This took into account the cost of lost tree value, tree removal, and tree replacement. 

Invasive pests have been incredibly problematic for our urban trees and native forests for the past century.  From Dutch Elm Disease to Chestnut Blight to Asian Longhorn Beetle, invasive insects and disease have changed the composition and ecological functioning of our forests as well as their look and feel.  So please, “Promise America” that you will not move firewood; that you will burn firewood where you buy it; and that you will plant a diverse selection of trees and not all the same species. Oh, and that old wooden baseball bat of yours may be more valuable than you think!  

Photo: http://stopthebeetle.info/

For more information, visit:

www.emeraldashborer.info

stopthebeetle.info

www.dontmovefirewood.org

Demystifying the Organic Food Controversy

Posted by: Alexis Alvey, CSU Denver Extension

Back a couple months ago, there was a big hoopla about a scientific article that reviewed the safety and nutrition of organic foods.  This eighteen page article was published in the esteemed journal, Annals of Internal Medicine by Stanford University* and concluded that, “the published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods.”  Wow, I thought.  Well that is a huge blow to organic producers, food activists, environmental leaders, and anyone else who gives a damn about where their food comes from!  My sentiments were felt even more strongly by others.  For weeks, my Facebook newsfeed was littered with status updates from various people and organizations proclaiming all sorts of things like, “Stanford is a pawn of big ag industry!”, “Academia should DIE!” and “Scientists don’t care about organic growers!!”.  Well, these emotional reactions kind of pissed me off a bit, because, one, I work in academia; two, I consider myself to be a scientist; and three, I went to an Ivy-League school (which isn’t a pawn of big ag industry, as least as far as I know).

In 2012, the CSU Denver Extension Vegetable Demonstration Garden at Harvard Gulch Park produced 750 lbs of organic food, which was donated to the St. Francis Homeless Shelter

So, like the good scientist that I am, I figured I would actually read the article before I made any judgments about the academic integrity of our higher education system.  Most of the eighteen page article was filled-up with nearly three hundred different citations and references, so it didn’t take me too long to read it.  I quickly realized that the authors were not presenting anything new; instead, they were merely reviewing existing studies, synthesizing the information, and trying to draw some sort of conclusion from 240 published studies on organic vs. conventional.  After reading the paper, the biggest conclusion I came to was that more studies are needed on this topic.  As the authors state, many of the studies they examined were “heterogeneous,” and from a statistical perspective, they were difficult to compare.  Furthermore, the authors admit that there have been no long-term studies comparing the health of populations consuming organic food versus populations consuming conventional food (controlling for socioeconomic factors of course).  These types of studies would be extremely difficult and costly to conduct, but are most certainly needed.  Nevertheless, the authors did find some really interesting results –

• The levels of the nutrient phosphorus are significantly higher in organically-grown produce compared to conventionally-grown produce;
• Organic produce has a 30% lower risk for contamination with any detectable pesticide residue than conventional produce;
• E. coli contamination risk does not differ between organic and conventional produce;
• And, the risk for isolating bacteria resistant to three or more antibiotics was 33% higher among conventional chicken and pork than organic alternatives.

I was also shocked to learn that bacterial contamination is really common in animal food products.  About 65% of both conventionally-raised and organically-raised chicken samples were contaminated with Campylobacter and about 35% of both were contaminated with Salmonella.  49 – 65% of pork samples were contaminated with E. coli for both conventional and organic.  Ewww.  How disgusting.  I will now be even more vigilant about cooking my meat, and will be more empathetic towards my vegetarian sisters.

Veggies growing at the CSU Extension - Jefferson County office

As I sat that night in my quite apartment munching on some hummus and baby carrots (and yes, the carrots were organic, but the hummus was not), I began wondering why people get so upset and so angry when they are presented with new scientific evidence that challenges their views and beliefs?  Perhaps the organic vs. conventional debate, like so many other issues in horticulture, can’t be boiled down to mere facts.  It is the passion, emotions, and values that underlie an issue that really motivate and move people.  There are so many disparate reasons why people buy or grow organic or conventional food that knowing the amount of phosphorus in an apple isn’t going to change people’s actions.  What about the apple grower who decides to use only organic pesticides because he is worried about chronic exposure to organophosphate pesticides?  What about the single mother on food stamps who is relieved to find conventional apples on sale for fifty cents a pound?  Is one person right and one person wrong?  There are many reasons why an individual may buy or grow organic or conventional food, and we should find it in our hearts to be nonjudgmental and open to all different viewpoints and choose what is best for us as individuals.

*Smith-Spangler et. al. Are organic foods safer or healthier than conventional alternatives? A systemic review. Ann Intern Med. 2012; 157:348-366