They need cold stratification. 6 to 8 weeks in fridge then warm at around 65 to 70. That would be best done in spring. Or you could sow outdoors in fall where you want them since you said you got loads and let nature do its thing. Or you could winter sow them in pots or plastic jugs cut in half, fill with medium and attach the top back on with holes cut for ventilation in the top and drainage bottom like a mini greenhouse.

This is a native plant forum ....

Esh, this has bothered me since I responded. I answered the specific question but would like to add that this plant is not only not native, it is considered a noxious invasive. I should have pointed that out in my answer but didn't want to come off offensively or opinionated.

I had this nightmare growing on my property when we bought it. I didn't think I would ever get rid of that mass of criss-crossing underground root system but I finally did with persistence and you have to dig deep to get the carrot type roots. I hate this plant. It does have pretty flowers but its ratty looking after blooming and not worth the space it takes up in the garden. There are so many better choices.

My advice is do yourself a favor and do not plant this.

This post was edited by GreatPlains1 on Tue, Jul 16, 13 at 0:37

Thank you Great Plains1 and esh_ga. I was not aware that this was considered an invasive. It was not described as such in my wildflower book. I will certainly take your knowledge about it under advisement in deciding what to do. Thank you for the objective reply AND the subjective 2nd post, Great Plains. Well stated on both counts !

Kaybee, I didn't realize it was considered an invasive species either but I looked it up after my first post and then thought "oh dear". Those wildflower mixes can be sort of misleading too along with some books, they often have non natives in the mix. I guess its native "somewhere" and grows wild so its included. I am not a purist so I will plant something if I just like it, native or not but I plant mostly natives.

But this bellflower really was a bear to get rid of and a warning should come with some plants so a body doesn't get stuck unawares and regret it later. At the time, I was just tired of the yearly ratty look it had all summer and had no idea it would be that bad to try to dig out.

By the way, if you end up "throwing them out" be sure you throw them in the trash, not outside. If you throw them outside then they may still germinate at some point and become a pest in that location.

Kaybee, I got your mail about wondering about the definition of a native plant. Wildflower books often include non-native plants that have become naturalized (Queen Anne's lace is another one like this) because it helps people to identify them. "Wildflower" does not mean native.

Non-native plants that have naturalized are still not considered "native" plants. The usual definition of a native plant in the US is a plant that existed here prior to any disturbance by explorers from other parts of the world. That usually means prior to the 1400's.

There are some native campanulas. Probably the best-known is campanula rotundifolia. Of course, it has a very different habit, being rather a small, creeping plant. I think it is very popular for use in rock gardens. Still, all campanulas have a certain charm, with their little purple bell shaped flowers.