Potassium: A Special K-Ration Feast For Your Roses

Providing a Potassium (“K”) feast for my roses in the six weeks prior to the first hard freeze of early winter has been an important part of winterizing my roses for over 20 years.  And yet, few, if any, rose-gardeners seem to know anything about it.  I have noted with pleasure the large number of rosarians reading my blog, not only in the U.S. and Canada, but also in other northern climates, such as Russia, Germany, France and the U.K., all of whom stand to benefit from learning this winterizing trick.  It doesn’t have to get as cold as Minnesota in your rose garden for this to be useful!

Here is a quote from Burpee’s American Gardening Series book Roses, by Suzanne Frutig Bales, which is the only place I have read about using Potassium for winterizing:

“Potassium is an important mineral for sturdy stems and foliage.  Weekly feeds of a gallon of liquid potassium (1 tablespoon of muriate of potash (0-0-62), dissolved in 3 gallons of water) per bush, or a granulated feeding of potash magnesium (0-0-22), during the six weeks before the bushes go dormant, will give the bushes an additional boost for winter, extending their hardiness into another hardiness zone, perhaps two.  Excess potassium, when available in greater amounts than nitrogen and phosphorus, is known as the ‘potassium feast’.  It will block the growth-promoting effects of nitrogen and phosphorus, hardening the canes in time for winter.” (emphasis mine)

Here in Minnesota, I begin my roses’ potassium feast in the second or third week of September.  That takes me through the end of October or beginning of November, which is about as late as I want to go.  There have been years, perhaps when I started a little too late, that I’ve had to thaw out my hose or turn off my water and turn it back on again in order to complete the sixth treatment.  You have to be the judge of when to get started in your area, but my advice is don’t wait too long, because it’s better to be too early than too late with this. 

I use Muriate of Potash (0-0-62) that I get in 50-pound bags at a local farm-supply store (Waconia Farm Supply near Minneapolis).  By the way, I define a farm supply store as a place that sells bulk fertilizers to farmers, not someplace that sells bird-seed to bird watchers.  A 50- pound bag of Muriate of Potash lasts me five years or more, because you really don’t use that much in a year (i.e., one TBP/three gallons of water).  I mix it in a clean, 60-gallon trash container and apply it with a sump-pump, through a hose and watering-wand.  This little trick of using a sump-pump for applying liquid fertilizers is a huge work-saver throughout the growing season.  I read about it in the Twin Cities Rose Club Newsletter several years ago. 

The Muriate of Potash I get from the farm-supply store is a reddish, crystalline substance that doesn’t dissolve as easy as most liquid fertilizers.  I use as much water pressure as I can muster, through a nozzle turned on all the way, to get it dissolved.  The sump-pump goes in after the tank is full.  It also makes your clothes red, if you get it on you (as I always do), but it washes out eventually. 

After about the third-week’s application, you will begin to notice that the canes of your roses are turning a pretty shade of deep red, so you can actually see them hardening-off for the winter, which is fun to watch.  When I tell people that I think the potassium feast actually does extend my roses’ hardiness into another USDA zone, they usually scoff at me.  All I can tell you on that score is that I haven’t lost a single rose to winter-kill in many years and I am not an aggressive winter protector.  (See my recent blog post: http://theminnesotarosegardener.blogspot.com/2012/08/no-tipping-please.html ). 

I also believe that this method of winter protection is particularly interesting for northern gardeners worldwide, as we see the continuing effects of climate change in the rose garden.  (See my blog post of several months ago:
http://theminnesotarosegardener.blogspot.com/2012/06/climate-change-in-rose-garden.html ).
While putting on liquid-potassium for six weeks seems to be a lot of extra work in the rose garden, I think it actually can reduce the overall work of winter protection, once you gain confidence using it in your own garden. 

I would really like to hear from you, if you take my recommendation and decide to start using potassium.  Please leave me a comment below or, better yet, send me an e-mail to:

jfalkersr@gmail.com.com .  If I don’t already have you on my blog distribution list, I will be happy to add you, as well as answering any questions you may have about growing roses in the northern hemisphere.

 Jack Falker in Minneapolis

Some Deadheading Examples

Last month I posted an article called "Deadheading (Or Things My Mother Told Me)".
http://jack-rosarian.blogspot.com/2012/06/deadheading-or-things-my-mother-told-me.html

 At the time, I didn't have any examples to illustrate what I was talking about, but yesterday, as I walked through one of my three Buck "Earth Song" beds, finishing up the process on some canes and snapping spent blooms off others, I saw a couple of perfect examples of what I want to show you about my somewhat different deadheading process, which, as I mentioned previously, goes back many generations to my parents' rosarian/agrarian roots in Europe.  Also, please note that this method was recommended in an American Rose article a few  years ago.

Here are the pictures I snapped yesterday with my iPhone.  Note the strong new growth jumping out right below the stems that I left on the plants on my initial deadheading pass a week or two ago.  If I had cut those canes back further initially, all of that strong, new growth would have been eliminated.  As soon as I snapped these pictures, I snipped off the old stems just above the new growth.  Using this method, I now have Buck "Earth Song" and "Carefree Beauty" roses topping six feet tall.

As usual, a picture is worth a thousand words!

No Tipping Please!

I know it’s early to be talking about winter-protecting roses  in mid-August but, if you decide to do what I recommend here, it’s time to get busy.  I would add that, while this blog-post is directed toward rose-gardeners in Minnesota, it applies anywhere in the Northern Hemisphere, where winter protection is necessary, because winter has definitely changed in the last ten years, putting the Twin Cities and environs squarely in zone 5, with other locations around the world in warmer zones, as well. (Take a look at my blog post: Climate Change in the Rose Garden:

http://theminnesotarosegardener.blogspot.com/2012/06/climate-change-in-rose-garden.html .

Because of climate change, extreme measures of winter protection, like the “Minnesota Tip”, in which roses are laid-over into trenches, in my opinion, seem to be a lot of unnecessary, back-breaking work for northern gardeners.  In addition, this method (which I personally used for many years) has the additional disadvantage of disturbing the natural growth pattern of the plants and often, when the roses are raised, results in bud unions and roots being too close to the ground surface for good horticultural practices.

There are several good, protective alternatives, which are most common in zone 5 (and incidentally work just fine in zone 4, as well).  All involve building up soil or mulch around the base of the plants and then applying leaf cover in some form, after the first hard freeze.  It has always seemed to me that doing this was much better for the plants horticulturally than tipping them out of their normal growth pattern.  Handling all the leaves in both the Fall and Spring is also a lot of work, but there is a method, commonly used in Chicagoland, that makes it a lot easier.  Simply take a leaf bag, fill it about two-thirds full of leaves, tie it up, cut a slit in the bottom of the bag, and push it down over the rose plant, which has been cut back to about 18 inches and bound together with baling twine.  This works even better if the leaves have been shredded before you put them in the bag.  Incidentally, do not use the new (and very expensive) compostable bags because they will fall apart over the winter leaving you with a pile of leaves, along with pieces of the bag, around each plant in the Spring.  The nice part of using the leaf bags is that you can simply roll them off the plants with the leaves still intact, dump them either in your mulch pile or yard-waste container and throw away the used bags.  The leaves remaining around the plants can be worked into the soil, along with the residual mounding mulch, making a good natural fertilizer. Construction blankets can also be successfully used as an insulator, in lieu of leaves or leaf bags, but they present the added problem of having to store them somewhere for eight or nine months of the year. 

Typically, with either method, the plants will be as well-protected and ready to prune, as they would be if they had been tipped; just a little shorter.  The major difference will be that their roots have not been disturbed and can immediately begin growing toward the first Spring bloom. 

Warmer winters have become the norm in other parts of the northern hemisphere, as well.  For example, looking at the Arbor Day maps in my climate change article, Chicago has moved from zone 5 into zone 6, as well as much of the lower-peninsula of Michigan, where previously it had just been around the Detroit area. This means that much lighter winter cover, with just leaves or several inches of wood chips, may be in order for these areas.  My advice would be, if in doubt, use the leaf bag method described above, but with less mounding necessary.

For those who are ready to accept my “No Tipping Please” thesis, it’s time to get busy right now.  Your bud unions are either above or right at the ground surface and they need to be covered immediately to get ready for winter and the mounding process to come.  My advice is to order in a load of mixed black dirt, peat and sand to raise the level of soil around your plants so that all bud unions are below ground level.  

Once you have given your previously-tipped roses a nice new layer of dirt and sand, you will want to mound them further in the late Fall before putting leaves (or leaf bags) around them.  If you don’t have a mulch pile started to use for mounding this year, order in extra dirt and sand to set aside and use this Fall.  Next Spring you can use the leaves and surplus mulch/dirt you take off your roses to build a mulch pile to use for the next winter’s mounding; and then, as you can see, it just goes on from there, year-to-year. 

As time and future winters go by, you will become more confident in the amount and type of cover needed each year.  In any event, I’m pretty sure you will agree with my “No Tipping Please” thesis going forward. 

E-mail me with any questions:  jfalkersr@gmail.com.

Jack Falker

8/17/2012