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fter the severity of last year’s winter,
so many of our members reported losing many, and in some cases, most
of their roses. Now with winter looming ahead, everyone is wondering
what is the best way to winterize their roses to avoid such losses.
Before following any advice found in rose
books and gardening magazines, we need to ask ourselves where the
author is from and what zone he is winterizing for. Advice for
winterizing roses in Arizona or in the southern part of the United
States won’t be of much help to us in New England. In addition, we
also need to understand why we winterize, make sure our roses are
‘zone appropriate’ and are in the best of health before they have to
endure the New England winter.
I have read several recent articles on
winter protection, but was curious to see what techniques were used in
the “good old days.” My curiosity brought me to old American Rose
Society Annuals and The Home Garden Handbook on Roses that
was published in the 1930’s. What I discovered was that the advice
given in the 1930’s and 40’s is basically the same as that given
today.
Most people think roses need winter
protection to keep from freezing during the cold winter months. In our
area this is not the goal. According to Frederick F. Rockwell’s book
The Home Garden Handbooks: Roses, “. . . it is not the cold
which causes winter injury to roses but the alternate freezing and
thawing, bright winter sunshine and drying winds, and late frosts in
the spring after the sap has begun to flow. Therefore, it is these
conditions rather than cold which winter protection should provide
against.”
Our goal in winterizing roses is to keep
them dormant and protected from the freeze/thaw cycle. During the
January “thaw” when temperatures may soar into the high thirties and
forties we want to prevent the roses from thawing and then re-freezing
a few days later when the temperature plummets. This constant thawing
and re-freezing results in winterkill. When the rose bush is uncovered
in the spring, black, dead canes are all that may be left. Roses need
to be kept dormant from the first cold of December through the last
frost of April. How we decide to do this depends on where we live and
even the micro-climate of our own personal rose gardens.
No method of winterizing will be
successful if our roses are not healthy. Roses that barely survived
the summer are not likely to survive the winter. Roses that have been
well cared for during the growing season will be better able to
withstand the hardship of winter. This means that roses should have
been fed regularly and kept disease and fungus-free. It should come
as no surprise that roses recovering from black spot or roses that are
scrawny and infested with other fungi are not going to survive the New
England winter. Roses are like people in this respect. If we go into
the cold winters run down and in poor health, we are more likely to
get the flu and colds. Taking good care of your roses in the summer
months is a key to having them survive during the winter no matter
what method of winterizing is used. It is also imperative that roses
in our Zone 6B be planted with the bud union several inches below the
soil.
I have read some interesting descriptions
of various methods of winterizing roses in zones colder than ours, and
the amount of work each takes varies. The Minnesota Tip is one of the
most remarkable and work intensive procedures I have read about. In
this method the canes are tied together and a trench is dug in the
rose bed right up to the base of the bush. The bush is partly dug up,
gently pushed over to lie down in the trench and then buried with
soil. The Minnesota Tip sounds like a very good method of winter
protection in a place like . . . Minnesota. It also sounds like an
incredible amount of work. Another method used in climates colder than
ours is one I saw used in “La Roseaie,” the rose garden in the
Montreal Botanical Garden. Tender rose bushes that need a lot of
protection are covered with special thermal blankets that are laid
over wooden frames built around the beds. This method is very
successful in this zone which is equivalent to USDA Zone 4.
Luckily most of
us don’t need to resort to blankets and the Minnesota Tip. Two
possible alternatives are rose cones and col-lars. A rose cone is made
of styrofoam and look like an upside down ice cream cone. (They
al-ways reminded me of dunce hats.) These white, very unattractive
cones are placed over the rose bush that has to be trimmed and/or have
its canes tied to fit inside. They also need to be weighed down to
keep from becoming air-borne and usually a hole is put in the top to
provide ventilation. The aesthetic effect of this winterizing
technique is not a pleasing one. Luckily this method is not as widely
used now as it used to be. The use of rose “collars” is a fairly
simple process of encircling the base of the rose bush with a material
such as a wire screen or plastic and then filling in this area with
leaves or mulch or compost.
In his 1930’s book, Rockwell states, “.
. . the simplest and most effective form of protection for garden or
bush roses is hilling up the soil about the plants.” This is the
method of winter protection Mike and I use and recommend. It is not
only fairly easy but also successful. Despite the harsh winter last
year we lost only two roses. It’s important to keep in mind that our
roses are “physically fit” going into the winter. We feed them on a
regular schedule from May to September as well as keep them disease
and fungus-free through a strict spraying program and make sure that
they are well hydrated through the growing season.
Our garden of
ninety bushes is winterized over the long Thanksgiving weekend which
follows Rockwell’s advice that the hilling up “should not be carried
out until just before the ground is likely to freeze hard.” The first
step in our winterizing process is to trim tall canes that may be
whipped around by winter winds. One of the most frequent questions
we’re asked is how much do we prune in the fall. The answer is that we
don’t prune our roses at all in the fall; we prune them in the spring.
We expect and accept some dieback and winterkill in the long canes
left on the bushes. Our focus is to protect the bud union. The second
step is to hill up the base of the bush, to a height of between twelve
and eighteen inches, with horse manure. If manure is not available,
mulch, leaves, compost or seaweed can be used instead. Once we’ve
hilled up our winterizing is done except for our potted roses. These
Mike buries in our manure heap or wood chips pile in the back of the
rose garden. We don’t spray our bushes with any oil nor do we remove
all of the leaves. If Mike feels very ambitious, after Christmas he’ll
collect the discarded Christmas trees in the neighborhood, cut the
boughs off and lay them over the rose bushes. The boughs act as a good
insulator and also add interest to the garden. When the time comes to
uncover the roses in the spring, the manure is just moved away from
the base of the rose bushes and remains in the rose bed. Black canes
may show above the hilled up roses, but the canes protected by the
hills of manure are green. Mike then prunes down until he can see the
creamy pith of the cane. This past spring some of our hybrid teas were
pruned to about four inches. It was hard to believe that they had
grown into full sized rose bushes eight weeks later.
It is important
not to remove the winter protection too early. In early April we may
be anxious to see how our roses fared, but remember to wait until “the
Forsythia blooms!” The blooming of forsythia bushes is nature’s way of
telling us that the soil has warmed up sufficiently. But the forsythia
does not bloom at the same time even in a state as small as Rhode
Island. The forsythias may be blooming in Pawtucket, but not in our
cool back yard in East Providence. So stifle the urge to uncover the
roses too soon. Also, if you think your rose bush is dead, make sure
it is really dead. A newly uncovered rose bush may look dead, but give
it a few weeks to bask in the warmth of the spring days to see if
there is any growth. We have shovel pruned a bush or two that we
thought hadn’t made it, only to find that its roots were still alive
and well.
Need more information on how to
winterize? Just come to our November meeting and take part in a
hands-on opportunity to winterize the roses in Roger Williams Park.
And if winterizing woes are getting you down, just keep in mind the
beautiful June blooms that make all the hard work worthwhile.
(February 2004 Rhode Island Rose Review)
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