Pollen Processing/Storage

I’ll outline the method that we use for pollen processing and storage. This isn’t the only method out there, this is just the one we’ve be using for years.

I made a comment about using once blooming roses as pollen parents, and I believe that Kim and Dave asked me how we stored the pollen. So, here you go guys!

First, I collect unopened flowers. Yes, this means I collect the bud stage (making sure the reproductive organs are not visible).

Take them back to the lab. Remove the petals, just as we would if we were going to pollinate it. Once reproductive parts are exposed, remove anthers. We place them in paper boats for a few days. (Just make sure anthers are dry so they will release their pollen!)

Place dried anthers/pollen in a small tube. Technically, they’re ‘microcentrifuge tubes’. I like them because they are small, transparent and have a screw cap. When I started working in the mid 90s, we were using 35 mm film canisters. I don’t like them so much because the top was a simple snap on/off sort of a thing and I never felt like it did a good job of keeping the pollen contained (but that’s just my opinion…).

[attachment 482 Pollenintube.jpg]

Once pollen is placed in the tube, it’s placed in a small clear box with a layer of desiccant in the bottom. We use Drierite, which is Calcium Sulfate (anhydrous).

This box is now ready to go to the freezer. Pollen for the ‘active year’ is stored in the freezer part of a refrigerator (which is generally around -20?C). Older pollen gets stored in an upright freezer that does not have ‘frost free’ feature. Why? Because in order to be frost free, the unit will increase the temperature to just above freezing for a brief period in order to allow any condensation to melt and drain away, and then re-freeze. I just feel that the temperature cycling is not good for long term storage (but once again, that’s just my own opinion).

[attachment 483 Freezer2.jpg]

I usually collect several vials of the same pollen and keep one ‘active’ and the others in storage. Sometimes, accidents happen and the pollen you needed/wanted goes missing or just get dumped out…but I’m sure none of you have ever had that happen!!

When we are not using the pollen it is stored in the freezer. When we use it, I move the box to the refrigerator for ~1 hour. Then, I get a small cooler and put a few ice packs inside and place the pollen box (with the desiccant) in the cold cooler and head to the greenhouse.

Pollen vials are only removed from the cooler when we are actively using them. They are replaced once we are done with that particular pollen and then we grab the next pollen and repeat the cycle. Once we are finished pollinating for the day, the pollen goes back to the freezer until the next day.

We never have any problem with condensation building up on the inside of the tubes. Yes, there can be a little that forms on the outside, when in use, but a quick wipe gets rid of it.


thanks for taking the time to share this, being soooo busy that you must be!

Questions, if I may:


How come you don’t collect anthers from some of the flowers where the stamens might be just showing? …is it to eliminate chance contamination pollens deposited on the opening flower from visiting insects?

I ask this, especially because I have found that some CV (thankfully not the majority) are real stubborn in pollen release from anthers despite there being plenty of anthers to collect and dry…and in a few of those stubborn types I have noticed that the pollen can be coaxed out of those dried anthers in much larger quantities when the anthers were deliberately collected from stamens where the flower just starts to show these reproductive parts, or even better when the flower has pretty much fully just opened that morning (compared to stamens harvested from unopened buds). Any advice there??


With what “applicator” do you apply the pollen… e.g. your finger? or maybe a brush?

Using a finger seems very popular here, and I must admit that is what I use, but those vessels seem awful thin for finger prodding!!

Not that it matters in this thread about what I do (LOL…I am much more interested to learn what you do / advise), but I sometimes freeze-store pollen in baby food jars…yes they are hugely more space-uneconomical if utilised on a numbers scale like yours, but for five or so jars in any given time I find they work ok for me in the freezer section of the fridge, and their shape and size allow me to prod the anthers to get the pollen on my finger.


Thanks for that detailed way you collect and store the pollen. Is it Ok to print your method out for reference later.

Hi George!

I hope that I’m never too busy to answer anyone’s questions! Right now, I’m traveling, so internet connections are not always reliable…

To answer your first question:

Yes, the reason we collect the flower at the closed bud stage is to prevent any possible contamination due to another insect visiting the flower.

I know what you mean about some cultivars not wanting to give up their pollen easily. I’ve always dealt with this issue by just collecting more flowers, but this may not be an option for you. I don’t see a problem with the method you are using the coax more pollen from the anthers. Just be aware of the insect activity in your area. If you see a bunch of pollinators buzzing around at 8 AM (and that’s when your collecting pollen), then you may need to cover the flowers with something. -If you want to go to that extreme! Of course, it’s not necessary, it’ll just have to be a choice you make.

2nd question:

Yes, we use natural hair brushes to apply pollen. Why? Because over the 15 years of me inhaling rose pollen I am now VERY allergic to it. I even went to an allergist every week for 3 years for treatments to help with this problem. The treatments have helped a lot, but I still try not to touch it and even wear a mask when I pollinate now.

Once we have used a brush to apply pollen, we dip it in 95% ethanol and let it dry before we use that particular brush again. In our heat, it doesn’t take long for the brush to dry.

I’m sure the baby food jars work very well. Space is at a premium in our lab. I don’t even want to think how many freezers we’d need to store all of that pollen in baby food jars!!! I’d probably have a lab full of freezers and nothing else!


Of course you may print the method out! You can even tape it to the wall and use it for target practice, if you feel so inclined!! :stuck_out_tongue_winking_eye:

Thanks for answering all the questions Nat, it is great to know about your experiences, and advice!

I’m allergic to rose pollen and oils. I quit bringing really fragrant roses into the home because I’d wake up wondering why I can’t breathe, lol. I have to actively remember not to touch my face in the months of May/June because of rose pollen. However, I still keep going at this hobby =)

I lost a decent dentist to his becoming highly allergic to tooth dust. Natural scents usually don’t affect me adversely, but the soap and fragrance aisles are death traps. I can count on collecting pollen and pruning roses (as well as digging in the dirt) to trigger the atopic dermatitis, particularly on my hands. Gloves don’t work. Can’t feel anthing and it’s like working with hot pan mittens on. Slathering up with hand cream first messes things up, so I just grin (figuratively) and tolerate it.

Yep, my allergies are concurrent with rose pollinating season, and often it’s really bad when I’m doing the pollinating, so I wonder if I’m not also allergic to rose pollen.

Michael when I am assesing the perfume on my new roses and those with strong fragrance , always give me hayfever.


Would you see any problem with putting a few grains of Drierite right in each vial with the pollen?



Well…personally, I wouldn’t do it. Drierite is sold in a ‘small rock/pellet’ form. You have to realize that before I use the pollen, I shake the vial. (And, I mean every time I’m about to do a pollination!) It’s helpful for me to see how much pollen is in the tube, and I think that within a very short time I would pulverize the Drierite grain into a fine powder. Then, I wouldn’t be able to tell if I was really getting any pollen on the brush, or if was just a bunch of Drierite dust…

How much of your “hay fever” is due to actual pollen and how much to the thrips you’ve inhaled? hehehe

Ugh! That remains me that when I was driving home from work on Thursday that I felt like I had things crawling all over me. Unfortunately, I did and they were aphids! Not the best discovery while traveling 70 mph down the road!

Too funny! MANY years ago, I have a favored old, red 1970 Camaro. It was raining and I’d collected cuttings to take out to The Huntington on a day off to propagate. The 14 freeway intersects in the Newhall Pass with the 5. That’s where the freeway falls down every major earthquake. The truck route is often the easier way to get through, and as I was ‘flying low’, I took it.

Suddenly, something hit the right side of my head fairly hard, startling the devil out of me. Instinctively, I slammed my right hand into the side of my head, causing me to ‘see stars’! Nestled in the cuttings I’d collected, and which were sitting on the passenger’s seat, was a HUGE grasshopper! Though nearly knocking myself more senseless, I missed him and threw the Camaro into a spin on the truck route. Fortunately, no one else was there and I slid to a stop in the mud on the outer shoulders which are used as run away truck stops. The grasshopper had flown to the passenger’s shoulder harness where I cleanly chopped him in half with my clippers (and half through the shoulder harness, too, for that matter!). After piloting that car out of the mud, I flew on out to The Huntington where the cuttings were duly processed, but I’m sure to check any cuttings I collect after that for “hitch hikers”! (No, I do NOT like grasshoppers!)

An associated funny, Clair Martin loved to tell the story of being out in the gardens dead heading while a couple intently studied something on a rose bud. Being curious, he walked over to see a huge grasshopper munching away with the man and woman focused on watching him. Instinctively, Clair reached over with his clippers and cut the blamed thing in half, right in front of their eyes! Both gasped! The man laughing, the woman incensed! LOL!

Fab stories…love 'em over a morning cuppa coffee, thanks y’all!

I’m definitely not much into movies / TV series etc, however this grasshopper story immediately brings me to thinking Kung Fu series and grasshopper (loved that name and character!!!)

As regards those poor critters…OUCH!!!

Now back to another cuppa…


Natalie, as a matter of curiosity, how many blooms do you guys generally pollinate in a session?


It varies greatly from year to year. 2 major factors are the temperature and how much help I have in a given season.

I don’t have all of my data here at home, but I can tell you that in 2008 we pollinated ~1200 and in 2010 we pollinated ~3300.

Because of the lack of winter this year, we were able to start sooner and we have already surpassed 3000 pollinations this year.

I bought some dessicant that’s silicon based and is little round balls. It was a refill for some sort of device. Now I put three or four of the little balls down in the pollen vial and it makes me feel good that I know they will suck up any latent moisture.[flickr_photo src=http://farm8.staticflickr.com/7085/7263557740_95e41542da.jpg nsid=66449618@N07 id=7263557740]dessicant[/flickr_photo]