I never heard of it. It would seem to me that the petroleum jelly would cause more problem that it would solve. Insects landing on it would get stuck and die. It would melt in the hot sun and run down the canes possibly causing problems. It would not prevent cane borers which could drill right through it. Nor would it prevent die back as it's not a sterile environment.
Better to use Elmers wood glue which dries hard and seals the cane end.

Second Karl's suggestion and opinion!

Jeri

I didn't think doing anything was very common. They use to have a pruning paint for trees until they disovered the tree does a better job itself.
I don't even use methiolade and bandages when I cut myself,LOL!

See:

http://www.google.com/search?hl=en&q=%22petroleum+jelly%22+prunning+&btnG=Google+Search&aq=f&oq=

Here is a link that might be useful: references

I think if cane borers are a known problem in your area, dabbing something on would be a good idea. If cane borers are not common in your area, I would not bother. Herbivores have been nipping stems from plants for hundreds of millions of years, and plants have adapted to heal themselves quite effectively.

Hoovb,
Good point. That's the only reason I seal the ends of my cut canes.

Henry,
The only reference I could find using petroleum jelly on rose cane cuts was in conjuction with copper, not by itself.It says;
"Some have used alternative, cheaper protection such as mixing a copper into either petroleum jelly or acrylic paint and applying this to the wounds."

Anything used should end up being an impervious seal to prevent cane borers from entering the end of the cane. I know some who have used thumb tacks. I tried it once and it works but I used lots of thumb tacks which ended up being thrown away. I didn't want to take the time to remove them.

There are people who actually seal cane ends after pruning??? I can't imagine doing that after pruning my 3000 roses. I don't have that kind of time!

See:

http://gardenersanonymous.typepad.com/the_gardeners_anonymous_b/2007/02/pruning_climbin.html

Here is a link that might be useful: link

Paul, maybe you need a gardener. JK.

Carla

Thank you all very much for your experience and advice. I will skip the vaseline :)
All the best,
~Victoria

Here's what I do with Vaseline. After I finish pruning, I take a nice hot bath then put vaseline on my feet and hands, cover with socks and gloves and make a cup of tea and relax. Nice soft feet and hands!!!!! If you get the vaseline in the baby section it smells very nice.....

Victoria, Good decision!! Publication over the last 5 yrs. or so from Ag. U's have shown that ANY pruning cut not be sealed as sealing prevents natural healing from occurring. Some gardeners just hang on to old ideas most of which have been debunked like wearing your golf shoes when cutting your lawn so you aerate it at the same time. !/4 inch spikes penetrating 2 inch high grass? I don't think so!!!!!!

If you have a serious problem with cane borers, then you have to seal. I don't have any borer issues, but a friend who lives 5 miles south does. She uses a "generic" version of Elmer's white glue and yes, she puts a drop on just about every cut when she prunes (over 100 plants).

Concerning what recent scientific research has found (or not found), the following reviewed, published 2007 paper gives what appears to be a balanced review of the pros and cons as published in the literature (starts on page 132 and continues on page 133).

http://www.texasoakwilt.org/Documents/Stewardship/Pruning_Article.pdf

Here is a link that might be useful: full scientific paper

I don't think that a paper that discusses the prevention of Oak Wilt fungus has much bearing on a discussion about sealing cuts on rose canes to prevent cane borers. You can't make grand assumptions about multiple pathogens based on a study of one pathogen on an entirely different genus.

trospero
That's why I tend to ignore most scientific papers. Many don't mention roses or the issue does not pertain to roses.
Haven't lost a rose to Oak Wilt fungus yet and no oaks have died from blackspot.

Paul, the original question was: "Someone told me that dabbing vaseline on the cut canes would help prevent disease and dissuade insects. Has anyone ever heard of this? Is it done? Is it insane?"

Later in the thread the following statement was made: "Publication over the last 5 yrs. or so from Ag. U's have shown that ANY pruning cut not be sealed as sealing prevents natural healing from occurring."

The authors of the Oak Wilt paper gave a general review of the prunning literature. I mentioned the specific pages where the review was presented.

My experience with articles on pruning and sealing of the cut is they mostly refer to slower growing trees than fast growing roses. Even the slowest growing rose grows faster than most trees. If pruned properly a tree will heal well and shouldn't be sealed. I've not seen a pruned tree get invaded by cane borers. Rose canes, on the other hand, often get cane borers within minutes of being pruned. Failure to seal can result in the loss of the cane end.

More often than not the canes grow quickly resulting in any pruning cuts being removed by subsequent pruning to shape the bush or winter comes and forces dormancy (in my area anyway) and winter dieback that removes the previous cuts long before they have much of a chance to heal.
On older thicker rose canes where a pruned surface may be
around for a few seasons, healing will occur. A cane borer getting into a thick cane, although unsightly, generally won't kill that portion of it. I've seen many a thick cane with borer damage growing merrily along and producing normal, healthy blooms. Unfortunately thinner canes damaged by borers do die back to the next bud past the damage resulting in a damaged cane that only produces blind growth or immature stunted blooms.
If one lives in an area where cane borers are not a problem, sealing the pruned cuts are not necessary. In my area, unsealed cuts are quickly attacked by cane borers.
Petroleum jelly would not protect. A substance that dries quickly and hard will.
These are my findings and experiences in my garden and don't necessarily reflect other gardens.

Apparently the National Gardening Association has heard of using petroleum jelly with hybrid tea roses, see:

http://www.garden.org:80/regional/report/arch/inmygarden/2744

Quote from reference cited: "It's a good idea to seal the cut wounds with petroleum jelly or a white glue to keep out any cane borers looking for a place to lay eggs."

Here is a link that might be useful: petroleum jelly recommendation for roses