A question about stratification .

Another question .
I have just been cleaning seed out of hips that I have collected at pruning time. These hips have been sitting out on the bushes during sub-zero nights [down to -4deg].
Will the seed still need more chilling time in the fridge ?


cheers. Rosalie

I've never seeded out nuts from hips, which where outside during the winter. But your -4° is not so much and the whole cold treatment will be sufficient to break the dormancy (if it is not inhibited by other stuffs inside the hip). Under controlled conditions the nuts are allways cleaned and separeted before the chilling.
Simply test it

cheers
Bernhard

edit:keep in mind that our conditions are a liitle bit different

Thanks Bemo. I know -4 isn't cold by european standards but it is in Western Australia Dreadful winter we have had here this year so far . Cold , and very very dry which go hand in hand , here.

As I don't imagine the pro growers sit and handshell their rosehips each year , how do they do it ?
I was just sitting at the table last night doing my few and enjoying a bit of quiet time after the kids were in bed . It was interesting too , seeing what shape and how many seeds etc were in each hip . Some hips were very fleshy and had a lot of "fruit" [for want of a better term] around the seeds and some were very thin walled with scarcely any flesh to speak of.
The fluff inside them makes a good substitute for itchy powder too.

cheers. Rosalie

I shell mine by hand. I cut them open with my secateurs and then use the blades to scoop them out. You might be surprised what the pro growers do. Sometimes you have very few hips to work with of a particular cross so the only way is to shell them is by hand. When they have really large numbers they will sometimes use a blender to remove the flesh. The seeds are really tough and usually make it through the blending process. The only instance I can imagine having that may is if you are collecting massive number sof hips to grow rootstocks by seed from multiflora plants.

When Bemo said that -4 isn't that much... he was more referring to the whole time. Day temperatures here are climbing upto 15 at the moment with nights down to the low minuses (-1, -2). This fluctuating cycle of low temps and moderate temps may not be enough to break dormancy. If it was a constant -4 maybe it would be.

Thanks Simon , that clears up that point . As our daytime temps have been rising up to low 20's last week [and still heavy frosts at night] , no one could blame the poor rose seeds for not knowing what to think.
Which brings me to another question do you have a recommendation then as to how cold and for how long I should refrigerate the seed for ? I have just sown some Russian Comfrey seed that I actually had to place in the deep freeze for a week ; well the seed packet said a week but I forgot about it and it ended up being 3 weeks
And that sort of brings me to another question . Is it only roses of the northern temperate regions that need this period of chilling ? or does it also apply to the others that are native to the warmer climates as well ?

cheers. Rosalie

Warm climate roses generally don't need so much. I sowed clinophylla seeds with none as soon as they arrived. Most still need at least some stratification... just not as long. Gigantea seeds take forever to germinate... not because of lack of stratification but because the seeds are hard as rocks.

Normal fridge temperatures are fine for statifying seeds. Thaty's about 3 degrees. I normally don't recommend a time because it depends on the variety. 6 weeks would be the min. though.