Exogenous seeds - have we learned anything new?

It’s been a while since the last discussion of this matter, and I have been wondering if any new knowledge has been gained recently regarding exogenous seeds. Are they sufficiently viable to warrant planting? Would aborting them early be beneficial to any normally developing seeds in the hip? Sadly, I had such poor germination from hips containing exogenous seeds over the past two seasons that I could not determine anything, and a little new advice now would be very timely!


My seeds from Aint She Sweet x Freedom like that came up. I think its fine if they dont get dehydrated or burnt during formation. At least that has been the case of Aint She Sweet and Proud Land which do that to me. I think Stamen from Rosarians Corner (John Sheldon) has experience concerning these types of seeds and might have stronger information for ya.

Thanks Jadae! Since the ones developing now were from indoor polliantions, they might be in remarkably better shape than the ones I’ve had occur outside. I think I’ll spare them.


Stefan, Awhile ago I asked the same question,but had no definative response to the post on the forum. The first two years of hybridizing ,I suspected the exogenous seeds were’nt viable,as Jadae stated,because of being burnt or dehydrated during formation of the hips. I had no germination at all. Recently,I’ve kept the exo seeds seperate as a test. The last two years I’ve found that placeing a newspaper cone cap over the hips after pollination,the germination rate of exo vs. in hip seeds was no different. Following are ‘04’ crosses with exogenous seeds. 1.Radox Boquet X Morden Blush 2.Frederic Mistral X Morden Blush 3.Aloha X Golden Celebration 4.Aloha X Lambert Closse 5.Aloha X Lichtkonigin Lucia 6.Aloha X Morden Centennial 7.Aloha X Prairie Sunrise 8.Pearlie Mae X Jan’s Wedding 9.Pearlie Mae X Lambert Closse 10.Pearlie Mae X Morden Blush 11.Pearlie Mae X Morden Sunrise. Brad.

In the article that I wrote for the Winter 2004 newsletter about our elephant and flea crosses, I mentioned that we did not treat the exogenous seeds any different from the rest. We did have quite a few exogenous seeds from the Harlekin hips regardless of the cross. Guess that is typical of that plant as I saw that even the OP hips had a lot of them showing. The germination was rather poor, and in going back and looking at the remaining seeds I can see that many of the ones that did not germinate were the exogenous ones. They were easy to pick out as they had one dark end which was probably from the sun. Will not mess with that seed parent again – lesson learned!

I’ve noticed that Cologne and Fragrant Plum has extraordinary amounts of exogenous seeds. Although this happens with cross pollinations, and not with the openly pollinated hips.

Well I many germinations of Cologne x Constance Spry, and I’m sure many of them were from exogenous seeds.

Interesting differences in results. Enrique, did you protect your developing seeds too?

I don’t know if I’d give up so quickly on Harlekin, John. I had a bunch of open pollinated seedlings from her and all have been extremely healthy with thick, shiny leaves and very mildew resistant - at least as adults. (I can’t recall if they had mildew problems as tiny seedlings).


No, I have not given up on those seeds as I know that hips from the climbers often take more than one season to germinate. I was just taking a peek to see what there was that did not germinate. Will keep them a tad longer, but will not use it as a seed parent again.

Hey Judith, would your little hip bonnets you made work for this type of seed set?

Perhaps, although the covers did reduce the burning of the seeds somewhat, I can’t say my bonnets made any difference in the germination rate of my exogenous seeds. I’ll try again this season with doubled covers.

As far as Harlekin is concerned, the hips I had were so huge, they had mostly endogenous seeds which germinated at about 2-1/2 to 3 months while still in the fridge stratifying. Maybe worth a second try, John? :slight_smile: Maybe somewhat weather related?

Exogenous seed bonnets! Say that ten times fast :slight_smile: I wouldnt give up on Harlekin either. It is an interesting blend in a rather small area of rosedom (climbers).

Here’s my take on the subject. It seems to me that timing plays a part in exogenous seed production in some varieties (with more exogenous seed production towards the latter part of the year). I have wondered if it is an adaptation to quickly ripen seed “before winter” by not developing a full seed coat. Perhaps this would explain the decrease in germination when allowed to dry out also.

I didn’t get many exogeneous seeds last season and any I did get I stratified along with all the rest. I figured it didn’t take any more or less effort to include them than it did the ‘endogeneous’ seeds. I’m interested in this question raised by Stefan:

Would aborting them early be beneficial to any normally developing seeds in the hip?

Maybe like disbudding exhibition roses to allow more resources to be channelled into a single bloom to get a bloom of higher quality and bigger size.

Maybe rehydrating them with a good soak for a while would increase germination???

Keep the outies…

they germinate well enough.

I had several germinations of Cologne X Constance Spry…

The best one of the group was grown from an outie seed.

Just don;t be touching and prodding them.