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.
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.
Good Advice
ReplyDeleteI have done this for several years. I also give each of the rosebushes a couple of tablespoons of Super Phosphate late in the season before they go towards dormancy. It moves slowly in the soils so also helps them through winter and with the boost for spring. Good blog you have here!
ReplyDeleteThanks Stan... Good idea on the Super Phosphate; I will put it out in a follow up blog. Send me an e-mail to jack@falkerinvestments.com and I will include you on my blog mailing list.
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