Monday, October 28, 2013

Rose Potassium Feast: Application #6

I put down the sixth and final liquid potassium application on my roses yesterday, getting them ready for winter.  In case you haven't been following my blog posts on this subject, here is a synopsis:

In the six weeks before the first hard freeze (i.e., down to about 25 F. at night), give your roses a weekly "potassium feast" in each of those six weeks.  Potassium blocks the growth-promoting effects of nitrogen and phosphorous, thereby hardening the canes in time for winter.  I've been doing this for more than 20 years and I honestly can't remember the last time I lost a rose to winter weather here in Minnesota. Of course, I do other things to protect my roses from the Minnesota winter, as well.  Here is my recent article on winter protecting your roses:

Here is a quote from Burpee’s American Gardening Series book Roses, by Suzanne Frutig Bales:

“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.” 

To clarify:  The proportions are: 1 TBP Muriate of Potash per 3 gallons of water (or 1 TSP per gallon).  So mixing in a 30 gallon trash container, you would use 10 TBP.  Apply one gallon of this mixture on each rose every week.  That’s not very much, but remember you’re repeating it six times. 

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.  My advice is don’t wait too long, because it’s better to be too early than too late with this. 

Here are a few pictures of yesterday's application, taken by Mary Eileen (a.k.a "The Head Deadheader"):

Each rose gets one gallon of the mixture for six consecutive weeks.  It has the added advantage of hydrating the plants weekly as we head into winter.  Note that it was a very nice day yesterday; a lot nicer than it has been for many of my sixth applications.

I mix the potassium in 34 and 64 gallon trash containers and pump it out with an inexpensive sump pump, through a hose and watering wand (you can see the pump's electrical cord going into the container). This little trick of using a sump-pump for applying liquid fertilizers is a huge work-saver throughout the growing season. Muriate of Potash 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.  Note how the potassium has red-stained the trash container in the picture below.  It will do that to your clothes too, but it washes out (eventually)  :)

Here I am with the 64 gallon container working on four of my Buck Earth Song plants.

I get Muriate of Potash (0-0-62) in 50-pound bags at Waconia Farm Supply, which is exactly 10 miles past the Minnesota Landscape Arboretum in Waconia.  A 50-pound bag of Muriate of Potash costs about $25 and lasts me five years or more.  For those of you outside of Minnesota, you will need to find a real farm supply store because it's pretty unlikely that you will find Muriate of Potash at your local nursery. 
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. 

 I believe that this method of winter protection is particularly interesting for northern gardeners, as we see the continuing effects of climate change in the rose garden. While putting on liquid-potassium for six weeks seems to be a lot of extra work, I think it can ultimately reduce the overall work of winter protection, once you gain confidence using it in your own garden. 

Here are two of my articles on the "potassium feast" from last year, as well as my recent article about winter protecting your roses:

1 comment:

  1. Rose is a very fragile plant which needs special care during the winters. This method is a good way to protect them from harsh winter winds and I hope it works well.