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.
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
Rhode Island Rose Review)