Seed germination article out

My short seed germination article came out in the most recent issue of HortScience!

Zlesak, D.C., The effects of short-term drying on seed germination in Rosa, HortScience


I compared keeping seeds moist after being removed from hips with allowing them to air dry for 4 days before submerging seeds of both treatments in water for 24 hours, stratifying them, and then following germination weekly over a few months. For some parents, short-term dring versus continual moisture didn’t make a difference, but for some like R. rugosa and R. rubiginosa short term drying reduced germination significantly. So, the take home message is if you do not need to dry seeds for storage or logistic reasons it may be better not to because of a chance of reducing subsequent germination. Some breeders harvest seeds and gather them them in envelopes allowing them to airdry until the whole family is harvested and ready to be bulked together for stratification.



Thank you David,

I often asked me this question about drying the seed or not. Thank you for this information. Very helpful.

I wonder if the results would of been the same with a 2 day soak.

Interesting. I did have a few batches I let dry out this year. We’ll see how they germinate.

One other thing I have to report. This week I have had 4 germinations from seeds that I have been pre-stratifying at room temperature (which I hadn’t done in the past). 3 of the 4 have had had 3 day bromelain soaks and then 1 day in H2O2. I usually only do a 1 day soak in bromelain, but I thought I’d try longer. The germinations are from:

Fabulous! x Betty Boop

Fabulous! x Miami Moon (at least it looks like MM)

Miami Moon (?) x OP

Love Me Tender x OP

Fabulous! is a wonderful germinator and the seedlings are very mildew resistant, however most of the seedlings I had from it did not make it thru our intense summer heat this year. I’ll try again with it. A lot of other seedlings from other mothers also succumbed. Maybe it was just a bad batch of soil.

David, thanks for sharing the article. One year I put seeds shelled from hips directly into ziplock bags without the moistened paper towels and noted a drastic reduction in germination as compared to other seeds treated by the standard method. Your paper confirms that observation.

I wish there were such a thing as a germination promoter that worked with all rose varieties. Wouldn’t that be nice?!

Jim Sproul

Congratulations on your article being published.

I have always been a seed saver, though roses only the last few years and have always allowed the hip/pod/fruit etc. to dry out completely then harvest the seeds and store them in paper envelopes for approximately 4 months. I then place them in the frig for 6 weeks in February take them out and soak them in water for 24 hours and plant under lights indoors.

My best germinators are the R. Rugosas which grow wild here in Maine.

Do you take the seed out of the still moist hip onto a wet papertowel into a plastic bag and into the frig immediately? Is mold a problem? How long are they in the refrigerator?

My questions probably have something to do with the long winters here, therefore long storage solutions. Thanks, Lori

Hi Lori. Good questions. With the rugosas I still got germination after drying, although significantly less. If you are satisfied with your germination % drying is fine. Anyway, what I did was what you described- seeds extracted from fresh hips and staight to moist paper towel. I stratified for 12 weeks in the fridge, even though that was longer than most of the roses I was working with really needed. I have long winters here in MN and the 12 weeks is what I typically do for everything so they don’t come up too early and my plant stands get too crowded with larger seedlings by spring. I have had a lot of mold problems with paper towels and difficulty separating roots growing within the towels. I’ve been happy with moist peat. There is less mold problems and then I can remove and pot them up from the baggies more easily. I have so many different crosses and such I just check the baggies weekly and pot what’s ready rather than take all the seed lots and plant them into separate pots and transplant from those pots later.

Take Care,


Thanks David. It’s been a great “hip” year and I think I’ll try some your way. I like that they are stored for 12 weeks. I’ve also had some luck with direct planting in the spring in a raised bed. My non-rugosas I have no luck with so I definitely need to try something different. Lori

at what conc. h2o2 becomes toxic to seedlings