Friday, June 29, 2012


JBs worse today than we've ever seen them.  Will spray Demand CS (pyrethroid Lambda Cyhalothrin) tomorrow morning.

Here's how they look this afternoon on Robusta.  Unfortunately, I can't spray these plants because they are on the edge of my raspberry patch with lots of ripe fruit (which the JBs are also attacking).

Couldn't decide which picture was worse, so here are all of them.  By the way, they all met their end right after I took these pictures.


Saturday, June 23, 2012

Twin Cities Rose Club Rose Show

The Twin Cities Rose Club had its June rose show on Saturday and Sunday, June 23 and 24.

The show, "Roses for the Jubilee" was a British Style rose show honoring Queen Elizabeth II in her jubilee year.

Because of our very warm Spring and Summer weather this year, many of the members gardens were already "out of bloom" so participation was somewhat limited, compared with past years.  However, as you can see from the pictures that follow, we had some very remarkable displays, especially in the "Cluster Flowered" and "Large Flowered" classes.

Wednesday, June 13, 2012

Climate Change in the Rose Garden

Here is an article I wrote for the Twin Cities Rose Club Newsletter in February 2012, based on research I did using State of Minnesota Climatology data.  The graph in the article indicates that not only have Minneapolis and St. Paul moved into USDA Zone 5, but also that they are headed toward Zone 6, based on the statistically valid trend line.  Also, the "Minneapolis Star Tribune" has just published an article  entitled: "Minnesota Warming Trend Gains Steam", which further validates my research findings. Here is that article:  .

Climate change has important implications to us as rosarians, not only in terms of what cultivars we plant, but also in how we winter-protect our gardens and how we care for them in the hotter summers.  As such, this is quite important to every rosarian in the country.

While this article is specific to the Twin Cities, it can easily be interpolated to other sections of the country by studying the accompanying National Arbor Day Hardiness maps, which I believe are more accurate than the recently published USDA data.  As I point out in the article, the USDA data are already out of date by seven of the warmest years in history.

Winter is Warmer Now

By Jack Falker

You might argue why it’s warmer in Minnesota these days, but you can’t deny the fact that it is warmer, and that has important implications for Northern Gardeners.

In January 2012, the USDA released a new Plant Hardiness Zone Map for the first time in 20 years.  It covers the 30 year period from 1976 to 2005, so it’s already seven years out of date and, importantly, those seven winters were among the warmest in the last 50 years.  More about that later, but that makes the new USDA data pretty unreliable.  The new map (shown below) is nonetheless interesting, so let’s take a look at what it says about Minnesota.

The USDA says that all of southern Minnesota has moved from Zone 4a, with annual extreme minimum temperatures (EMT) of -30 to -25, to Zone 4b with annual EMT of -20 to -25.  If you look very carefully at the map, you can see a small area in the Twin Cities, mainly Richfield and Bloomington (including the airport), which is in Zone 5a (EMT -15 to -20).  This seems counterintuitive to the “heat island” theory, since the downtown areas are not included.  It looks rather like the area along the Minnesota River Valley has been measured.  This is much easier to see if you look at the interactive map the USDA provides, and zero-in on the Twin Cities.  Here is the address: .  If you play with it a little, you can actually get down to the streets in Bloomington and Richfield that are shown in Zone 5a.  In that regard, it is also counterintuitive that Zone 5a doesn’t extend into South Minneapolis and Edina!

Those of you who read my article “Are the Twin Cities in Zone 5 or Zone 4?” published here several years ago, will recall that I cited an extensive study that was done in 2006 by the National Arbor Day Foundation showing that essentially the whole Twin Cities area, including the inner-ring suburbs, plus the areas of southern Minnesota along the Mississippi and St. Croix rivers, are all in Zone 5a.  Based on my own record keeping and gardening experience in Edina, as well as regular observations at the Lake Harriet rose garden, this is correct.  The 2006 National Arbor Day Foundation Zone Map is included at the end of this article.  It is also available on line at: . This further raises the question: Why is the USDA still so far behind the curve?

Let’s take a look at the historic EMT data for Minneapolis/St. Paul from the University of Minnesota Climatology Working Group site (  For example, if we take the same 30 year period as the just released USDA study (1976-2005 inclusive), the average annual extreme minimum temperature (EMT) was -19.4 degrees, which is right on the low edge of Zone 5a.  However, if we update these numbers for the 30 year period just ending (1983-2012) the average annual EMT becomes -18.6, which is more convincingly in Zone 5a. That average is definitely being “pulled” by the warmer winters of the last 10 years.  For the 10 years 2003-2012, the average EMT is -16.1 degrees, which is closing in on Zone 5b (EMT -10 to -15).  Although the winter of 2012 is still with us, it appears that our EMT was -11 degrees on January 19th, which is edging close to Zone 6a (EMT -5 to -10).  Having lived in Zone 6a (Detroit) until 1977, I can attest that this winter reminds me a lot of southern Michigan!

To see just how much things have changed in the last ten years, it is very interesting to look at the 50 year period 1963 to 2012 (inclusive), when the average annual EMT was -21.1, ( Zone 4b).  But again, the last ten years pull the average, so if you look at the 30 year period 1963 to 1992, you get a better historical picture, with an average annual EMT of -23.4 degrees.  What jumps out at you, as you look back at the 1960s and 1970s, is just how much colder it was back then.  For example, there was a period in 1970, between January 17th and January 21st when it didn’t go above zero for 4 ½ days, with a low temperature of -34 and a high of -3.  Now that was a zone 4 winter!  Another thing that jumps out at you is how many -20 degree days occurred in December and February, during those decades.  This is something we haven’t seen in several years.  Here is a graph of that 50 year period. Notice the upward slope of the graph, right out of Zone 4 into Zone 5.  And, If you follow the statistically valid trend line, it takes us into Zone 6 within ten years.

How This Affects Northern Gardeners

First, we need to remember that we are still in Minnesota and it can get pretty cold for a few days in January, even though the EMT averages indicate that the Twin Cities are now on the northern edge of Zone 5.  Note on the chart above that the temperature dropped to -21 in 2009 (one degree lower than Zone 5), but it didn’t stay that way for long, like it would have 30 years ago.

Probably the most important message to take away from this discussion is that, unless you live well outside the Twin Cities area, the “Minnesota Tip” method of winter protection amounts to a lot of unnecessary, back-breaking work.  The tenderest of hybrid tea roses, planted with their bud unions below the ground surface, should survive very nicely in the Twin Cities, with some mounding and a cylinder of leaves or a leaf bag, with its bottom opened, pushed down over the cut-back and tied-up plants.  These are tried and true methods of winter protection in Zone 5, Chicagoland (which is now, by the way, in Zone 6).  For roses that are a bit hardier, such as the Bucks, a three-inch layer of wood mulch should be sufficient.  My favorite Buck rose, "Earth Song", is rated Zone 5 hardy, and I have experimented successfully with just wood- mulching and natural snow cover over the last few years. The plants die back to the snow cover or the mulch, but grow aggressively, as soon as they are pruned and fertilized in the spring.  If I want to save more of the canes, I push a leaf bag over certain plants.

While the long-term implications of global warming are ominous, the short-term benefits for Northern Gardeners are obvious. In addition to less-rigorous winter protection for our roses, and the resulting lighter workload, we can also look forward to planting a greater variety of perennials and trees in the future.  And, let’s face it, walking around and playing outside in the winter months has gotten a lot more pleasant than those years when it didn’t get above zero for days on end.  Enjoy it!

Monday, June 11, 2012

Japanese Beetles Have Arrived in Edina

After several days in the 90s over the weekend, the Japanese Beetles have arrived in my garden, about two weeks ahead of schedule.  This promises to be a very bad infestation, because of our warm Winter and Spring.

I picked the first JB off Robusta (squirmy in my bare hand) and popped it in my pond, where a big goldfish had it for supper; a fitting end.

So, I will be mixing up some soapy water in my big coffee can tomorrow morning and scouting the rose beds for the first JB wave.

I'm really not looking forward to this.

Saturday, June 9, 2012

Terraced Rose Beds in Edina, Minnesota

Here is a picture of my terraced rose beds on a steamy June 9th afternoon.  In the foreground is the Buck "Prairie Harvest" and to the right are "Winnipeg Parks" and "Morden Blush".  In the left background is Buck "Prairie Star" and in the right background is Buck "Earthsong". These are totally winter hardy beds, with three inches of wood mulch serving both as ground cover and winter protection.

Friday, June 8, 2012

Deadheading (Or Things My Mother Told Me)

I grew up in a rose garden.  Some of my fondest childhood memories are of “Peace” and “Chrysler Imperial” nearly reaching into my bedroom window, and filling my room with fragrance every summer morning. And, yes, I knew the names of those roses as a child, because they were part of my life.  What I didn’t know was that “Peace” had just been smuggled out of France before the German occupation in the early 1940s.  Our next door neighbors in Detroit (zone 6) had extraordinary rose gardens, as well, and I wandered through those gardens often.  I cut the lawn of one of those neighbors (50 cents a week, front and back) and cultivated their rose beds.  I remember standing behind their garage on a summer morning, totally mesmerized by an extraordinary, bright-red, fragrant climber on the back fence.  I was 10 years old and it was 1950.

 Fast forward 35 years to 1985; I’m 45, living in Minneapolis, and back in Detroit visiting my parents.  My mom, then 77, leads me into her rose garden one summer morning and says: “Here, Jack, let me show you how to deadhead a rose bush.  “Ahhh, sure mom”, thinking, “here’s some useless knowledge”.  So, Mom says:  “Ok, you just take the spent bloom between your thumb and forefinger and snap it off; watch for where the new growth begins later, and cut it back to that point.”  I filed that away in 1985, among all the other seemingly unimportant things my mother told me growing up.

Well, it wasn’t too long after that, when the rose-bug bit (how did my mother know this?).  I had been growing vegetables for years, but had never planted a flower, much less a rose.  My first one was “Tournament of Roses” and others followed, especially “Peace” and “Chrysler Imperial” and, being an academic, I set out to read everything I could find about growing roses.  I collected a personal library of rose books, including some rare, old classics, checked some out of the library, and tried to learn everything I could about roses (after all, I grew up in a rose garden).  Then I joined the American Rose Society so I could start reading “American Rose”, which I have done religiously for many years.

What I found out about deadheading from all this study was that my mom (who was descended from multiple generations of European agrarians) had to be wrong about deadheading.  What all the new rose books said was: “Cut the dead flower off the flower stalk just below the first true leaves”; or “Cut the stem at a 45 degree angle, ¼ inch above the first set of leaves having five leaflets….  The dormant bud in the leaf axil will be stimulated to grow into a new shoot that will produce a flower within six weeks” (in other words, half the summer!).  And that’s what I did for years.

Fast forward another 20 years or so, and I discovered an article about deadheading in an issue of “American Rose”, which contended that the prescribed method of cutting to the first five-leaflet stem destroys much of the hard-won growth of the rose over a growing season.  Instead, the author called for the straightforward method of simply popping off the spent bloom between one’s thumb and forefinger and subsequently watching to find the point at which new growth would begin.  OMG… That’s what my mother told me!

So, I gave it a try and have been doing it ever since.  Here’s the trick:  Begin by simply popping off the spent bloom between your thumb and forefinger.  There’s a little swelling below most blooms at that point, which snaps off very easily.  You can feel it when you grasp below the spent bloom with your fingers.  This leaves a stem sticking up which begins to wither in a few days.  As you pass through the garden over the next week or so, you will see where new growth is beginning and you simply cut back the stem to that point with your garden scissors.  So, it’s a two step process that you finalize as you deadhead the next week’s spent blooms.  You can shortcut this method to a one step process (which I often do) by using your garden scissors to cut the stem back to a logical growth point the first time through, typically at the first three-leaflet set.  But this varies for each type of rose and you can use your own judgment as to where the best growth is beginning. For example, it doesn’t work the same for clusters of flowers on floribundas and shrubs, where you will want to cut off the whole spent cluster.  But, following this precedent, don’t cut back too far and you’ll get better and quicker growth for the next cluster.

What’s very interesting is that my old classics on roses: “How to Grow Roses” by McFarland and Pyle, copyright 1937, and “Hennessey on Roses” by Roy Hennessey, copyright 1942, say nothing about deadheading.  However, in his section on pruning, Roy Hennessey says: “Why sacrifice or greatly weaken your rose bush…when if you treat it with consideration it will thrive, increase in size and be able to give you finest blooms for years to come….  How far down do you prune an apple tree to get the best apples? The more foliage you have working on the first crop of bloom, the better the results for the rest of the season.”

When you use this little deadheading trick, what’s most noticeable is how much quicker your roses grow and how many more blooms you have over a full season.  Try it, experiment with it, and you will come to understand and like it.  Moral of this story?  Sometimes the old ways are the best ways.  And always do what your mother told you (especially if she grew beautiful roses)!

Let me know how it works for you; e-mail: with observations or questions.