It works on evergreens because they are evergreen, losing moisture through the leaves when the upper root zone is frozen and not yielding up moisture. I doubt if it helps to winterize roses or other deciduous plants.

It might help some with cane desiccation but that would be it. So if you use it just do the canes. The leaves are going to shrivel and blow off probably anyway so it would be a waste.

Yes, that had been what I'd been thinking, that sometimes the spring brings withered, dried out ends of canes that need to be removed and that often that goes with a dry, windy winter, rather than a cold one. But maybe that is more dependent on how much water their roots get, rather than loss at the top. I did finally bring in the hoses and timers for the season, but we've had rain every week anyway, so they should be starting the winter okay.

I think the benefits to the roses, if any, are probably minimal enough that it is not worth doing. By contrast, the broadleaf evergreens nearly always benefit as they keep going throughout winter and are the most marginal plants I grow in this zone.

I used to use it all the time to prevent RRD. Now that I no longer spray, I haven't gotten around to spraying that and only that.

I do believe that the company that makes it does now suggest that it can be used on roses -- possibly to fight RRD.

Sammy

I used it this fall on my roses. The first year I used it, I had a lot more viable cane left in spring, but I also had put burlap over the trellis and bushes. Last year I didn't use any Wilt Pruf and still did use burlap and had less cane to work with. So, I am going back to using it on the roses. It does seem to help some. Give it a try! Can't hurt!

Guess you're right, can't hurt to try. It wouldn't take too much work to do it, as long as the daytime temps on the upcoming weekend are above freezing (predictions are for highs in the upper thirties through mid-40s, which will still be quite a change from 60F this past Saturday).

I have never heard what you say about Wilt-Pruf as an RRD preventative, Sammy. Is there research that supports that? Would be worth asking Ann Peck what she knows of it. And, if it works, how long would the protective effect work for? Presumably when one winterizes with this stuff the waxy coating stays on the foliage for quite a while. I would be willing to try it as a preventative if a once every 2-3 month application would do it. Come to think of it, I'm not sure where the RRD mites go in winter--do they stay on the plants or are they killed? I know that once the virus is there, nothing one can do gets rid of it, but I know nothing about the perdurance of the actual mites on the plants they've infected.

My friend who recommended it has a wonderful garden, but I do not have her permission to quote her. She does spray, but not as frequently as many people do. She just adds it to her spray. At first when I called the manufacturer of Wilt Pruf, they said I should not use it because I would be using a product in a manner in which it was not suggested. But later they began suggesting the use of it. You could probably find some threads on the use, but it would go back maybe 5 years. If you search, it could be this site or the antique site.

Good luck.

Sammy

I found this on a prior thread--not clear to me whether there was any efficacy to the treatment and sounds like you'd have to do it often. But perhaps your friend is going to spray anyway, so then adding it in wouldn't hurt:

>Some have tried anti-transpirants to disrupt the mites, or miticides or Neem to try to kill the mites, and the disease still comes."

I am interested in knowing who specifically tried these methods and reported that the treated plants got RRD?

Hi Henry,

I thought I had posted a response in this thread earlier and only realized today that I hadn't when I found the temporary file I was using to write this response still on the computer's desktop. I'm sorry for the delay.

Anyway, I tried Wilt Pruf briefly in late May and again in mid June of this year. I only had enough Wilt Pruf for maybe 2/3 of the roses in May, but in June after the new Wilt Pruf purchase arrived I thoroughly gave them all a full shower of that anti-transpirant. For awhile, maybe three weeks, I didn't toss out any more plants to RRD (of the 48 that were sitting in pots all together with a few roses planted nearby), and perhaps if I'd tried reapplying it every couple of weeks, that would have worked. However, one variety--two plants--was horribly affected by the Wilt-Pruf treatment itself in June (and I think I recall that neither of those roses had gotten a full application of Wilt Pruf in May, if they had gotten any at all). The many other roses didn't show a very significantly bad response, but both General Gallienis reacted noticeably within half a day. One recovered, and the other one didn't. I am thinking that perhaps the really hot weather might have been the wrong circumstance in which to apply Wilt Pruf--that General Gallieni might have gotten by with Wilt Pruf applications in cooler weather. I don't really know why that variety was differentially affected though. Anyway, I quit trying to use Wilt Pruf regularly for protection during the summer and haven't gone back to using it, at least not at this point. By July I was back to having RRD-infected roses to toss out.

If anti-transpirants do work for RRD protective purposes, you'd have to remember to keep doing it regularly (and I've no idea of the definition of _regularly_ here), since I did a thorough job in June and by fairly early in July was having to toss plants again.

I did try Neem a few times, but nothing in a programmed way and nothing else I did worked either (pyrethrin). Just tossing the roses as soon as you see several symptoms seems the best bet, unless you've been keeping such a close eye that you know the disease symptoms are only a few days' old, in which case cutting out a cane is probably well worth a try.

I kind of think RRD is gone from this yard now, but with cooler weather here now, it's going to be difficult to know for sure. The three roses that have had a single RRD-diseased cane removed are going to have to spend the winter isolated in a pot until I can see what the new growth looks like next spring. Somewhere recently I read that sometimes a plant can already have RRD but can take up to a year to show symptoms.

Best wishes,
Mary

I have been applying it mid-December for about 5 years. I am convinced it reduces cane die-back in the spring.

Good to hear. Sounds like it would't be bad to do if I am doing the other shrubs. This year I haven't yet gotten to it, but the weather has been warm and wet in December, so I may yet try...

Put it on half the plants and measure the damage next April.

Otherwise you could be starting a lifetime of superstitious routine use ("I used WP and I have roses, so I better keep using WP.")

If I do it at all (which has to do with temps this weekend and how much time it takes to wrap X-mas presents) I'll just do a few in one bed and leave the others in that same bed un-done.

I don't think this is the best zone to test this prediction in though, since I only lose substantial amounts of canes every 3rd year or so. That mostly has to do with weather in Jan-March being very windy, dry and cold. Today it got to 60 again and we had thuderstorms--I still have rosebuds outside that I hope to bring indoors to open. So it is hard to think about real winter weather. However, I know from a lot of past experience that my broadleaf evergreens do benefit from Wilt-pruf spraying. If I had to guess, I'd expect the rose advantage to be slight to none, but might give it a try anyway.

Oh yes, Michael - nothing can beat doing your own little trials especially since there is no covert agenda to sell stuff.

There is a new product that may be of use, see:
http://www.eurekalert.org/pub_releases/2011-12/asfh-nef121411.php

Here is a link that might be useful: link for above

Thanks Henry. Sounds like this product could have a huge impact on winter agriculture. Seems possible it could extend the fall blooming season for roses if sprayed on buds and supporting new growth. Or, in my climate, we often have a setback in spring, as plants grow out prematurely only to have the new growth frozen. Is there any indication that it would protect hardened stems, that is, extend the actual plant hardiness of roses?

michaelg, I have not tried it. Part of my hybridizing is to test for natural hardiness.

A google search gives the manufacture's "claims".

Here is a link that might be useful: Google search

Thanks Henry for the link and the information. Like Michael, I would find it really helpful if there were a way to protect new growth in spring from the wild weather changes we frequently get. The springs that their new growth freezes (sometimes more than once) and they have to start over always take a toll on their energy and blooming power. I'll read what they say about application/makeup of this stuff.

Concentrate to make 4 gallons of spray costs $80-$100 plus shipping. Smaller quantities are available. Shop around, prices are highly variable.

Note that, although it last up to four weeks, it says to reapply to new growth. New growth is probably what rose growers would be concerned with

Let me know if you find a source you like for it--I'll probably try to get some to try in March, which is generally when the highest likelihood of killing to new growth is. I can do 2-4 week applications until early May, by which time the danger has generally passed and I'm getting the first blooms.

I will run it as a controlled expt with treated and untreated adjacent plants and will update this thread as to whether it made a difference. Let me know if you try it also Michael.

It doesn't appear Wilt-Prufing is going to happen this season, as everything else ate my weekend and now we are heading out of town shortly. But I think this treatment might have greater promise anyway, so curious to know whether it helps.