Pumpkin Honey

You might want to get after it now. The two apiaries I found (using google) that produce Pumpkin Honey, claim a mid-September Harvest. Both were small west coast apiaries, and don't appear to sell in bulk. Hope that helps.

Wrathwilde

This doesn't make a whole lot of sense to me. Right now you should be harvesting pumpkins not pumpkin honey. Any honey produced from a pumpkin patch should have been taken off months ago after the pumpkin plants had blossomed. Before the bees moved on to another source. This is about the only sure way to get the floral source you are after. It would also mean that the colonies were taken to a rather large pumpkin farm for pollination. If colonies were doing some kind of pollination and then taken to another location or even stayed in the farm after the bloom they will move on to another source. Any frames that weren't filled with pumpkin blossom will be filled with wildflower. Of course there is a possibility that it was all sorted, I guess.
My mentor, from smell, can tell when the bees are bringing in honey from goldenrod and I would assume that the same could be done for pumpkin. But to my knowledge the above is the proper way to collect a specific floral source honey.

I see your concerns (blossums and time of year) but in my limited experience would want to taste the honey first. In fact I would like a squash blossum honey but have never heard of such a thing.

In my celler lies some mead made from honey from so called pumpkin blossum. I used a D-47 and fermented it dry. I can't remember if I used KO3 and/or potassium sorbate but can't taste those chemicals in the after taste. My records show that I backsweetend it (one cup to 5 gallons) but now am thinking it's ready for competition. In hind sight, I'm thinking it could use a little oak. Also, be careful as this honey is very floral and kicks off massive aromas. Probably to the point of calling the aroma of the mead perfumey (unfortunately, BJCP judges may deduct for this). But that may be the backsweetning although I have another mead (not backsweetend) that would suggest otherwise.

Pumpkin honey is wonderful and orange in color, but I always seem to hit my suppliers just after they sell out. Pumpkins bloom over a long period of time, but the hives should be off the crop by now. That does not mean it is extracted or ready for bottling yet....