Putting honey on stigmas before pollination??

I was visiting with a rhododendron breeding friend last week and she says she uses honey on stigmas when she emasculates and doesn’t want to wait a day or so for the natural secretions to build so she can pollinate right away more effectively. I saw her make some pollinations. She uses raw unfiltered honey.

Have others done this? I wonder if the sugars, etc. could enhance/speed pollen tube growth and maybe help make some normally incompatible crosses possible.

It’s an interesting idea and perhaps something I might consider for otherwise impossible matings. I would worry here that the honey wouldn’t be compatible with our high evening humidity. I know honey doesn’t spoil by itself because the water content is completely occupied but what about when added water hits it? And, I don’t need ANYTHING extra to attract the ants! California is one GINORMOUS ant hill!


Hi David

My main concern for this is, honey has hydrophilic properties, this could effect the moisture content within the pollen grain and gamete. When checking for pollen fertility, a 20% sugar solution is used. Maybe if the honey was diluted down to this concentration, results could be very good.

Cheers Warren



I had wondered about using a sugar water solution on hesitant roses when the stigmas of such don’t generally look “sticky” and ready to accept pollen at any stage during normal development. I thought about trying such on speculation that some reluctant mothers might just fail to trigger tube germination.

Not sure what benefits honey would have over a sugar/boric acid solution. I suppose there are things in honey that might overcome the so-called “pollen population effect”, but bees don’t generally want to encourage germination of the pollen which they store, and in the above thread referenced by Henry, it was suggested bees create enzymes to actually quell such.

To that end, a Brewbacker Kwack medium might be the better solution for such. (Have there been subsequent improvements on this solution?)

David, how critical is the sterility and purity of the water in your pollen-germination studies? I have yet to try such as I don’t even own a microscope.

Thanks everyone! For the water in the pollen germination assays I’ve just used RO or distilled water in the lab. That is a good question how much city water with chlorine or water with various minerals would impact the results.

It might be interesting to see what pollen does under the microscope when exposed to honey…
(David, do you bother with Ca, K, or Na in your pollen germination mix?)

Good one Henry, for impatient types that cant wait until noon … like myself

… oops sorry meant … “Good one David” … slip-up part of being impatient

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Used it this summer and can’t comment on if worked … but from a pragmatic point of view l am hopeful as it eliminates one level of finicky movements and dropping pollens paint brushes and tweezers

In another post there was discussion of calcium aiding pollen tube growth, right?

So could we mix a little calcium in with sugar water, add some to a vial of pollen and shake it up, then brush the resulting pollen slurry onto stigmas? I wonder how long you’d have to do all your pollinations…30 minutes?

You could try making the solution be different pH levels, and try it on different types of roses.

It would be especially interesting on rugosas, I think. They are somewhat finicky about accepting modern pollen. It would be interesting if calcium (in what form?) or adjusting the pH of the pollen slurry would influence hip set.

Might as well dump in some ethyl methanesulfonate, too…just kidding, you chemists. Half kidding.


In another thread I linked to several articles dealing with supplements to pollination. Among other things, sucrose, calcium, boron and alterations of pH. In one case, the authors chose three seed parents with stigma exudate of pH 3, and three others with pH 8. I think we may assume that some species yield pollen tubes that favor low pH, and other species’ pollens favor high pH.

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Many thanks for the suggestion and for further input. This is a really interesting matter ! May I ask you, whether you have tried to put a calcium + sugar water solution on the stigmas before pollination ? In positive case, did you get some valuable insights?

I just used this solution gently on a very small scale, because the time frame for fertilization was nearly over and only less usable stigmas were availabe. After wetting these stigmas I waited 30 minutes before pollination. Different pH levels I have not taken into consideration. Due to the small amount of my first test attempts, I am cautious about saying it made a great difference, but I felt it could be of some help.

Definitely, I think that it’s worth a more quantitatively application.

Tried honey once. I switched to slight moistening of saliva on my index fingertip. Used it to pick up anthers and pollen wipe from bags and stick to them onto miscreant teflon behaving stigmas.

Works only once per dab for me and if wind non existent it stays in place … compared to falling off. Re-wet and dab a couple of times.

Figure with loose science don’t have to worry about residual adverse protein and digestive enzyme effects as drys quickly in sun and they should be denatured and non - functioning.

Not seen adverse effect so far, 128 crosses - 50% took - in data can’t tell if helped or hindered, but it sure reduced frustration level.