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- I'm here today at the Tulsa Rose Garden,
and like many other public gardens across the country,
this garden has suffered serious losses
due to rose rosette disease.
Now, we've learned a lot from this garden
and similar ones, as well as in research trials,
about management of rose rosette.
And so I want to talk a little bit today
about tips for trying to keep your landscapes healthy
and free of rose rosette.
This rose garden's been here since the 1930s,
and about 20 years ago,
there were more than 5,000 roses on this property.
And unfortunately, when rose rosette arrived,
it was an epidemic, and they're down
to a just a few hundred roses at this site.
So, some of the things that we've learned,
looking back, is that when it first showed up,
the horticulturalist did not recognize
that rose rosette was the problem.
They saw the unusual shoots and distortion,
but they just clipped it off and kept working.
And what we've learned now is that pruning
is just not a very effective management strategy.
And so it would have been better,
they probably could have slowed down rose rosette
at this site if they had dug up
and removed those symptomatic plants.
There is often a lag period, even though
you may not see symptoms on your plants.
A lot of times, the microscopic mites are present
and the virus may be all throughout the plant,
just not currently expressing symptoms.
So the main recommendation is to discard plants
if you observe they have rose rosette.
One of the other issues was that
those gardeners continued to work in the landscape.
And as they moved around,
they could have been carrying those microscopic mites
on their tools, or their clothing, and so
as they moved from diseased areas into healthy areas,
they could have carried those mites.
So now, we encourage landscapers
that have more than one planting of roses
to always start with healthy plantings
and work with the suspicious, or plantings
where you've had rose rosette
as late in the day as possible.
And so, if any of those mites
carrying the virus are present,
we don't move them into healthy areas.
So at the end of the day, laundry your clothing
and come back fresh the next day.
For tools and equipment,
there's many different sanitizers that can be used
to clean those tools and remove those mites.
Some other things that this garden is doing,
just like others, is that
they are diversifying their planting.
So, back when they had 5,000 roses here,
they basically had a monoculture.
And so when the disease showed up,
it just raced through the planting.
And so now, we see lots of other types
of plant material being incorporated with the roses.
So this increase in diversity has helped quite a bit.
In research trials, Dr. Mark Wyndham
at the University of Tennessee
has done some work with green barriers,
such as ornamental grasses.
And if we have these larger barrier plants
planted in between roses, the mites,
if they were to move from this rose
and try to launch on the wind to other areas,
those green barriers intercept and are helping prevent
the rapid spread of rose rosette.
So anytime you can include different sized plant material
and increase your diversity, that's great
in breaking up the disease cycle.
We also believe that one of the ways
that rose rosette was spread in this garden
was the use of leaf blowers.
Often landscapers, after pruning roses,
will use leaf blowers and they'll pile those clippings,
and then scoop them up all at one time.
It's likely that using leaf blowers around roses
could launch some of those mites into the air,
so they move into other areas.
Also, using leaf blowers to clean up leaves
or long clipping should not be used anytime around roses.
Now, one other aspect of management
is, of course, the use of miticides.
And we talk a little bit about that
in one of the other videos in this series,
but at this particular rose garden, one great practice
has been what we call dormant pruning,
followed by the application of an oil.
So, in the winter months,
about a month before the roses break dormancy,
we remove most of those leftover leaves
and blooms from the previous season, cut back the plant,
and then apply an oil at the dormant rate.
It's a high enough percentage of oil
that it's smothering any overwintering arthropods.
And it also helps reduce other diseases,
like black spot or anthracnose that also affect roses.
Throughout the season, once the plants break dormancy,
miticides can be applied to help prevent
or suppress mite populations,
and consult with your county extension office
about what products are labeled for use in your area.
Some other things that are being done
is looking at different cultivars,
not just planting one cultivar, using different types,
they have different disease and insect resistance,
and so it's likely that there are some cultivars
out there that are tolerant or resistant to rose rosette.
There's another video in this segment
that talks more about that.
And so hopefully, we'll have some resistant
or tolerant cultivars to report in the future.
Another aspect of management is keeping your plants healthy.
And so anytime your plants are healthier,
they're better able to resist pest and disease issues.
And so maintaining fertility,
irrigating during periods of drought,
mulching to help conserve soil moisture,
and prevent erosion, is really useful.
If you're looking for other information about rose rosette,
please review other parts of this video series,
or visit the roserosette.org website
or the Combating Rose Rosette Facebook page.
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