Q.cold stratifying
started cleome seeds in pots, is it too late to cold stratify?

It is probably a bit late to cold stratify at this point unless you live in a region that has warm winters. This is a fun plant and good cut flower. Not only do some seeds need stratification, germination is also based on soil temperature, and once germinated day length, so this should be taken into consideration. If you think it is too late for this year you should be able to find 6 packs or 4 inch cleome that will take a significantly less time to bloom than starting from seed. They grow fairly large and it doesn't take many to fill a bed.